WO2012169262A1 - Method for producing molybdenum granulated powder and molybdenum granulated powder - Google Patents

Method for producing molybdenum granulated powder and molybdenum granulated powder Download PDF

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Publication number
WO2012169262A1
WO2012169262A1 PCT/JP2012/057399 JP2012057399W WO2012169262A1 WO 2012169262 A1 WO2012169262 A1 WO 2012169262A1 JP 2012057399 W JP2012057399 W JP 2012057399W WO 2012169262 A1 WO2012169262 A1 WO 2012169262A1
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molybdenum
powder
granulated powder
producing
water
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PCT/JP2012/057399
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French (fr)
Japanese (ja)
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山口　悟
勉 森岡
斉 青山
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株式会社東芝
東芝マテリアル株式会社
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Publication of WO2012169262A1 publication Critical patent/WO2012169262A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/045—Alloys based on refractory metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B22F1/148—Agglomerating

Definitions

  • the present invention relates to a method for producing molybdenum granulated powder and molybdenum granulated powder.
  • Molybdenum (Mo) is used in various fields as a heat resistant material because it has a high melting point of 2620 ° C.
  • it is applied to thermal spray materials, sintering furnace plate materials, electrode parts, magnetron stems, sputtering targets, and the like.
  • the material for thermal spraying as a raw material in the state of Mo powder or Mo rod.
  • the plate material may be manufactured by sintering, or may be manufactured by combining rolling and forging.
  • electrode parts and the like may be manufactured by processing a plate material, drawing a wire by wire drawing, or manufacturing by a sintering method.
  • Mo powder or molten Mo is used as the initial raw material.
  • Mo molten metal is used by a method in which raw materials are melted and cast into a desired shape.
  • the method using the molten Mo is a method in which the molten metal is poured into a mold, and is a relatively simple method that can be processed into a large shape.
  • Patent Document 1 discloses a sintered electrode for a cold cathode tube having a U-shaped cross section (cup shape).
  • Patent Document 1 a cup-shaped electrode having a diameter of about 1 to 2 mm is manufactured using a sintering method.
  • molding process, a degreasing process, a sintering process, etc. are implemented with respect to Mo powder.
  • the sintering method has been progressed mainly by improving the degreasing process and the sintering process.
  • paragraph [0027] of Patent Document 1 it is disclosed that the degreasing step is performed in a wet hydrogen atmosphere while the sintering step is performed in a hydrogen atmosphere. As a result, the sinterability is improved and the production yield is improved.
  • Patent Document 2 of International Publication WO2011 / 004887A1 discloses a method for producing high-purity molybdenum powder having an average particle size of 0.5 to 100 ⁇ m.
  • Patent Document 2 discloses a molybdenum powder in which the proportion of primary particles is 50% or more.
  • improvements have been made on the Mo raw material powder, the degreasing process, and the sintering process.
  • the production yield did not necessarily reach 100%.
  • Such a phenomenon also occurred in the same way for a Mo sintered body using Mo powder to which a dopant such as potassium was added.
  • the present inventors have investigated the reason why the yield of a product using Mo powder added with a dopant as an initial raw material is not improved. As a result, it was found that the variation in the size, density, fluidity, etc. of the Mo granulated powder caused a variation in the filling density and supply amount in the molding process, which caused the product yield to decrease. In addition, when Mo granulated powder is used as the thermal spray powder, there is a problem that the supply amount to the thermal spray flame varies and the characteristics as the thermal spray film are not stable. As a result of pursuing this cause, it was found that there was a cause that the management according to the average particle size of the intended granulated powder was not performed in the granulation step. The present invention has been made to solve such problems, and provides a method for producing molybdenum granulated powder capable of stabilizing the quality of Mo products (powder or sintered body) and improving the yield. For the purpose.
  • a method for producing molybdenum granulated powder includes a step of injecting water into a container and heating the water to 50 to 80 ° C., a step of adding a binder to the heated water, A step of preparing a molybdenum-containing aqueous solution by adding a molybdenum powder having an average particle diameter of 1 to 10 ⁇ m to which at least one of a potassium component, an aluminum component and a silicon component is added while stirring, and a spray for dispersing the molybdenum-containing aqueous solution.
  • the molybdenum-containing aqueous solution is applied to the spray dryer in which A / B is in the range of 50 to 700.
  • a step of preparing a molybdenum granulated powder by dispersing and drying the molybdenum-containing aqueous solution is preferable to further carry out a sieving step of passing a sieve having a mesh size 2 to 3 times the average particle size B to the granulated powder after completion of the step by the spray dryer.
  • the average particle diameter B of the molybdenum granulated powder is preferably 20 to 150 ⁇ m.
  • the rotational speed A of the rotating plate of the spray dryer is preferably 5000 to 16000 rpm.
  • the potassium component is preferably added in the range of 100 to 1000 ppm by mass in terms of a potassium element simple substance.
  • the aluminum component is preferably added in the range of 100 to 1000 ppm by mass in terms of a single aluminum element.
  • the silicon component is preferably added in the range of 100 to 1000 ppm by mass in terms of silicon element.
  • the binder is preferably at least one of polyvinyl alcohol powder, polyethylene glycol powder and carbomethyl methylcellulose powder.
  • the volume of the binder is preferably 3 to 20 parts by volume.
  • the apparent density of the resulting molybdenum granulated powder is preferably 1.3 to 3.0 g / cc.
  • the molybdenum-containing aqueous solution preferably has a pure water amount of 0.2 to 1 liter when the amount of molybdenum powder is 100 parts by mass.
  • the spray dryer preferably dries the molybdenum granulated powder while supplying hot air of 150 to 300 ° C. Moreover, it is preferable that the spray dryer performs drying of the molybdenum granulated powder in a reduced-pressure atmosphere of atmospheric pressure or lower. Moreover, it is preferable that the fluidity of the obtained granulated powder is 50 sec / 50 g or less.
  • the molybdenum granulated powder of the present invention is characterized in that it contains at least one of a potassium component, an aluminum component, and a silicon component and has an apparent density of 1.3 to 3.0 g / cc.
  • the average particle diameter of the molybdenum granulated powder is preferably 20 to 150 ⁇ m. Further, when the total amount of molybdenum powder is 100 parts by volume, the volume of the binder is preferably 3 to 20 parts by volume. Further, the fluidity of the molybdenum granulated powder is preferably 50 sec / 50 g or less.
  • the method for producing molybdenum granulated powder according to the present invention in the granulation step, while adding water to a predetermined temperature and stirring, supplying the dopant-added molybdenum powder and binder, Since the average particle diameter and the rotational speed of the spray dryer are controlled within a predetermined range, molybdenum granulated powder having excellent average particle diameter, apparent density and fluidity can be produced.
  • a method for producing molybdenum granulated powder includes a step of injecting water into a container and heating the water to 50 to 80 ° C., a step of adding a binder to the heated water, A step of preparing a molybdenum-containing aqueous solution by adding molybdenum powder having an average particle diameter of 1 to 10 ⁇ m to which at least one of a potassium component, an aluminum component, and a silicon component is added while stirring, and a spray for dispersing the molybdenum-containing aqueous solution.
  • the molybdenum-containing aqueous solution is applied to the spray dryer in which A / B is in the range of 50 to 700. And a step of dispersing and drying the molybdenum-containing aqueous solution and preparing a molybdenum granulated powder. .
  • FIG. 1 shows an example of a process for preparing a molybdenum-containing aqueous solution.
  • reference numeral 1 is a container (a container for preparing a molybdenum-containing aqueous solution)
  • 2 is water
  • 3 is molybdenum powder (dope-containing molybdenum powder)
  • 4 is a binder
  • 5 is necessary.
  • 6 is a molybdenum-containing aqueous solution.
  • water is poured into the container. As this water, tap water, pure water, ultrapure water, or the like is used. Pure water and ultrapure water are water that contains almost no impurities.
  • pure water has a specific resistance of 10 4 ⁇ ⁇ cm (25 ° C.) or higher
  • ultrapure water has a specific resistance of 18 ⁇ 10 6 ⁇ ⁇ cm (25 ° C.) or higher.
  • Examples of pure water and ultrapure water include distilled water, ion exchange water, and RO (Reverse Osmosis) water.
  • pure water or ultrapure water it is preferable to use pure water or ultrapure water.
  • pure water since the preparation of ultrapure water is complicated and causes cost increase, it is preferable to use pure water. Further, when it is not necessary to control the mixing of impurities, the cost merit is increased by using tap water.
  • the heating temperature of water is preferably 50 to 80 ° C., more preferably 60 to 70 ° C.
  • the material of the binder is not particularly limited, but is preferably at least one selected from polyvinyl alcohol (PVA) powder, polyethylene glycol (PEG) powder, and carbomethyl methylcellulose (CMC) powder.
  • PVA polyvinyl alcohol
  • PEG polyethylene glycol
  • CMC carbomethyl methylcellulose
  • Polyvinyl alcohol, polyethylene glycol, and carbomethyl methylcellulose are soluble in water because they are water-soluble. Also, for example, it is preferable because it does not remain as an impurity in the sintered body because it burns away in the sintering step.
  • the average particle size of the molybdenum powder is the average particle size of the primary particle size.
  • the value obtained by the FSSS method Fischer method is defined as the average particle size. If the average particle diameter of the molybdenum powder is less than 1 ⁇ m, the Mo powder is too small to be manufactured, which causes an increase in cost. On the other hand, if the average particle size exceeds 10 ⁇ m, the primary particle size is too large and it becomes difficult to stabilize the characteristics of the granulated powder.
  • the average particle diameter of the molybdenum powder is preferably 1 to 10 ⁇ m, more preferably 2 to 5 ⁇ m.
  • the molybdenum powder tends to aggregate more than necessary. Therefore, it is preferable to add a small amount, for example, 0.5 to 2 kg.
  • the molybdenum powder after confirming that the entire amount of the binder is dissolved in heated water. If the binder is added in a powder state, it can be visually discriminated whether or not it has been dissolved.
  • polyvinyl alcohol powder when used as the binder, when the polyvinyl alcohol powder is completely dissolved in water, the water before adding the molybdenum powder becomes translucent.
  • the molybdenum powder after the binder is added. The same is true for polyethylene glycol and carbomethyl methylcellulose. As shown in FIG.
  • the volume of the binder is reduced. It is preferably 3 to 20 parts by volume.
  • the binder serves as an adhesive that bonds the molybdenum powders together when forming the molybdenum granulated powder. Therefore, when the total amount of molybdenum powder is 100 parts by volume, if the amount of binder added is less than 3 parts by volume, the amount of binder is too small and uniform granulated powder may not be obtained.
  • the addition amount of a binder exceeds 20 volume parts and becomes excessive, a binder will enter too much into the clearance gap between molybdenum powders, and it will become a granulated powder with a large dispersion
  • the molybdenum-containing aqueous solution preferably has a water content of 0.2 to 1 liter when the amount of molybdenum powder is 100 parts by mass.
  • the spray dryer is charged with an aqueous solution containing molybdenum.
  • the amount of water is less than 0.2 liter with respect to 100 parts by mass of the molybdenum powder, the amount of water is too small and the viscosity of the molybdenum-containing aqueous solution increases, and it is difficult to stably supply it to the spray dryer.
  • the amount of water exceeds 1 liter, the amount of water is too large and it is difficult to stably supply water.
  • the supply of the molybdenum-containing aqueous solution to the spray dryer can be automated by mechanization.
  • water 5 may be added as necessary. Since the water is heated to 50 to 80 ° C., there is a possibility that the amount of water may change greatly due to the evaporation of the water when the binder and the molybdenum powder are added and mixed. If a large container with a volume of 20 liters or more is used as the container 1, the remaining amount of water is added to 70 to 40% after mixing the amount of water with the binder and molybdenum powder at 30 to 60% of the final amount. It is possible to adjust the amount of molybdenum powder and water by adding it. In order to make it easy to visually confirm whether or not the binder is completely dissolved in water, a method of additionally adding water is effective.
  • the molybdenum powder of the present invention is a molybdenum powder to which at least one of a potassium component, an aluminum component, and a silicon component is added.
  • a potassium component the aluminum component, and the silicon component, compounds such as single elements, oxides, and complex oxides are used, respectively.
  • the potassium component is preferably in the range of 100 to 1000 mass ppm in terms of potassium element simple substance.
  • the aluminum component is preferably in the range of 100 to 1000 ppm by mass in terms of a single aluminum element.
  • the silicon component is preferably in the range of 100 to 1000 ppm by mass in terms of a silicon element. If the amount is less than 100 ppm by mass, the effect of addition is small.
  • a dopant may be 1 type or may add 2 or more types.
  • a potassium component, an aluminum component, and a silicon component are components called a dopant.
  • the recrystallization temperature is increased and the high temperature strength is increased as compared with high purity molybdenum.
  • Secondary processing includes wire bending processing, wire bending processing, plate material (plate material made of Mo sintered body) rolling processing, bending processing, punching processing, and the like. Further, when a wire is used, non-sag, high-temperature vibration resistance, and blackening resistance can be improved.
  • ammonium dimolybdate (NH 4 ) 2 ⁇ Mo 2 O 7 )
  • Mo oxide ammonium dimolybdate
  • Potassium silicate is added to the Mo oxide so that the amount of elemental potassium element per elemental Mo is 100 to 1000 ppm by mass.
  • pure water is added, kneaded, heated to 100 to 140 ° C. with stirring and dried to obtain a molybdenum oxide powder to which a dopant is added.
  • the dopant-added molybdenum oxide powder can be heated and reduced at 1000 to 1200 ° C. for 2 to 5 hours in a hydrogen atmosphere to obtain a dopant-added molybdenum powder.
  • the above shows an example in which potassium is added as a dopant.
  • silicon or aluminum is added as a dopant, silicon alone or a silicon compound, and aluminum alone or an aluminum compound are added, respectively.
  • potassium silicate was used as the potassium component, the invention is not limited to this, and other potassium compounds may be used.
  • when adding 2 or more types of potassium, aluminum, and silicon what is necessary is just to add each element or compound and to obtain a dopant addition molybdenum powder.
  • the purity of the dopant-added molybdenum powder is not particularly limited, but the total of Mo and the dopant is preferably 99% by mass or more, and more preferably 99.9% by mass or more.
  • Main impurities of the molybdenum powder include Fe (iron), Ca (calcium), and Mg (magnesium).
  • Other impurities include Ni (nickel), Na (sodium), Pb (lead), Bi (bismuth), Cd (cadmium), Cu (copper), Mn (manganese), and Sn (tin). It is done.
  • the measurement of the purity of molybdenum is Fe (iron), Ca (calcium), Mg (magnesium), Ni (nickel), Na (sodium), Pb (lead), Bi (bismuth), Cd (cadmium), Cu (copper) ), Mn (manganese) and Sn (tin) are subtracted from 100% by mass.
  • Fe iron
  • Ca calcium
  • Mg manganesium
  • Ni nickel
  • Na Sodium
  • Pb lead
  • Bi bismuth
  • Cd cadmium
  • Cu copper
  • Mn Manganese
  • Sn tin
  • gas components such as oxygen, are mentioned as impurities other than the said metal impurity.
  • the amount of oxygen is preferably 7% by mass or less, and the amount of nitrogen is preferably 7% by mass or less.
  • FIG. 2 shows an example of a granulation process using a spray dryer.
  • reference numeral 1 is a container containing a molybdenum-containing aqueous solution
  • 6 is a molybdenum-containing aqueous solution
  • 7 is an inlet for the molybdenum-containing aqueous solution
  • 8 is a rotating plate that disperses the molybdenum-containing aqueous solution 6 into fine droplets.
  • 9 is a granulated molybdenum powder
  • 10 is an outer wall of the spray dryer
  • 11 is a recovery container for the molybdenum granulated powder.
  • the molybdenum-containing aqueous solution 6 adjusted in the above process is poured into the charging port 7.
  • the charging speed to the charging port 7 is preferably 10 to 80 cc / min.
  • the input speed is less than 10 cc / min, the input amount is too small and the mass productivity is deteriorated.
  • the charging speed exceeds 80 cc / min, the charging amount becomes excessive, and the characteristics of the resulting granulated powder vary.
  • the charged molybdenum-containing aqueous solution 6 is supplied onto the rotating plate 8 via the charging port 7.
  • the rotating plate 8 rotates at a constant rotational speed.
  • the molybdenum-containing aqueous solution 6 is supplied to the rotating rotating plate 8, it is repelled by a certain amount, and spherical molybdenum granulated powder 9 is formed by surface tension.
  • the molybdenum granulated powder 9 falls along the outer wall 10 of the spray dryer and is collected in a molybdenum granulated powder collection container 11.
  • the average particle diameter of the molybdenum granulated powder is highly related to the rotation speed of the rotating plate.
  • the present invention is characterized in that A / B is controlled in the range of 50 to 700, where A (rpm) is the rotational speed of the rotating plate and B ( ⁇ m) is the average particle diameter of the molybdenum granulated powder.
  • a (rpm) is the rotational speed of the rotating plate
  • B ( ⁇ m) is the average particle diameter of the molybdenum granulated powder.
  • a / B which is the ratio of the rotational speed A of the rotating plate to the average particle diameter B of the granulated powder, is less than 50, the rotational speed of the rotating plate is insufficient with respect to the average particle diameter of the intended granulated powder. Therefore, the average particle size B of the intended granulated powder cannot be obtained. Moreover, when A / B is less than 50, it becomes a granulated powder having a larger average particle diameter than the average particle diameter B of the intended granulated powder. On the other hand, when A / B exceeds 700, the rotation speed A of the rotating plate is too high with respect to the average particle diameter B of the intended granulated powder, and thus the average particle diameter B of the intended granulated powder is obtained. Absent.
  • a / B exceeds 700, it becomes a small average particle diameter with respect to the average particle diameter B of the intended granulated powder.
  • a / B By controlling the value of A / B in the range of 50 to 700, a granulated powder having an average particle diameter within a range of ⁇ 50% with respect to the average particle diameter B of the intended granulated powder can be obtained.
  • the average particle size B of the intended granulated powder is 50 ⁇ m
  • the average particle diameter of granulated powder uses an enlarged photograph, and makes the maximum diameter of the granulated powder reflected there the particle diameter, and the average value of 100 granulated powder is the average particle diameter of the granulated powder.
  • the average particle size B of the granulated powder is preferably 20 to 150 ⁇ m. If the average particle diameter of the granulated powder is in the range of 20 to 150 ⁇ m, it can be applied to various applications. Further, the rotational speed A of the rotating plate 8 is preferably 5000 to 16000 rpm. When the rotational speed A is in the range of 5000 to 16000 rpm, the molybdenum-containing aqueous solution 6 is effectively repelled efficiently on the rotating plate 8, and molybdenum granulated powder having a target average particle diameter is easily obtained.
  • the spray dryer preferably dries the molybdenum granulated powder while supplying hot air of 150 to 300 ° C. Supplying hot air of 150-300 ° C into the outer wall of the spray dryer to dry the molybdenum granulated powder, thereby evaporating the moisture in the granulated powder and strengthening the bonding force between the molybdenum powders by the binder Can do. As a result, it is possible to effectively produce molybdenum granulated powder having a target average particle diameter. Hot air is supplied into the outer wall 10 of the spray dryer from a hot air supply port (not shown) and exhausted from an exhaust port (not shown).
  • the spray drier carries out the drying of the molybdenum granulated powder in a reduced-pressure atmosphere below atmospheric pressure.
  • ⁇ Granulated powder in the range of 50% can be obtained.
  • the apparent density of the resulting molybdenum granulated powder is preferably 1.3 to 3.0 g / cc.
  • the average particle diameter of the molybdenum granulated powder is measured using an enlarged photograph. If it is this measuring method, the average particle diameter on an external appearance can be judged.
  • the variation in the amount of molybdenum inserted into the molding die occurs, and the pores in the sintered compact may become larger than necessary. If the apparent density of the molybdenum granulated powder is less than 1.3 g / cc, the amount of molybdenum in the granulated powder is too small, and this causes a variation in quality in the subsequent commercialization. On the other hand, when the apparent density exceeds 3.0 g / cc, the molybdenum powder is tightly packed, and it is difficult to stably manufacture with a spray dryer. The apparent density is measured by a measuring method based on JIS-Z-2504.
  • the fluidity of the obtained granulated powder is 50 sec / 50 g or less.
  • the fluidity is measured by a measuring method based on JIS-Z-2504.
  • the fluidity is an index indicating how smoothly the granulated powder moves (flows).
  • the fluidity is good (fluidity 50 sec / 50 g or less)
  • the supply to the molding die at the time of commercialization can be carried out smoothly and rapidly.
  • the granulated powder has good handleability.
  • liquidity is favorable means that the shape of granulated powder is close to a sphere.
  • the aspect ratio is 1.5 or less.
  • FIG. 3 shows an example of the shape of molybdenum granulated powder.
  • reference numeral 3 denotes molybdenum powder
  • 9 denotes molybdenum granulated powder
  • L1 denotes a short diameter of the molybdenum granulated powder
  • L2 denotes a long diameter.
  • the aspect ratio is obtained by “major axis L2 / minor axis L1”.
  • An aspect ratio of 1.0 indicates a state close to a true sphere.
  • the molybdenum granulated powder of this invention excellent in average particle diameter, apparent density, and fluidity
  • a method of carrying out a sieving step is also effective. Excessive granulated powder can be removed by carrying out the sieving step. As a result, the average particle diameter can be further controlled.
  • molybdenum granulated powder having excellent average particle diameter, apparent density, and fluidity can be efficiently produced with high yield. Therefore, the granulated powder according to each product can be manufactured with a good yield.
  • the use of the granulated powder include thermal spraying powder, raw powders of various sintered bodies, and the like.
  • the production yield can be further improved by changing the average particle size according to the shape of the molding die. For example, in a sintered body having a thickness of 1 mm or less, the average particle diameter of the granulated powder is about 50 ⁇ m, and in a sintered body having a thickness of about 5 mm, the average particle diameter of the granulated powder is about 100 ⁇ m. It is possible to efficiently fill the molding die.
  • Example 1 (Examples 1 to 7 and Comparative Example 1) A dopant-added molybdenum powder shown in Table 1 and polyvinyl alcohol (PVA) powder and pure water were prepared as binders. Water was poured into a stainless steel container, and while the water was heated and stirred, the polyvinyl alcohol powder was added and all the added polyvinyl alcohol powder was dissolved. When all the polyvinyl alcohol powder was dissolved, it was confirmed that the solution was a translucent aqueous solution. Thereafter, a total of 40 kg of molybdenum powder was added in an amount of 1-2 kg. When the molybdenum powder was agitated, pure water was added as needed for the amount of water that was insufficient due to evaporation.
  • PVA polyvinyl alcohol
  • Example 1 Samples using polyvinyl alcohol powder as a binder were designated as Examples 1 to 5. Further, a sample using polyethylene glycol powder as a binder was Example 6, and a sample using carbomethylmethylcellulose powder was Example 7. On the other hand, the molybdenum containing aqueous solution which concerns on the comparative example 1 was prepared by processing like Example 1 except the heating temperature of water having been 35 degreeC. Table 2 below shows the conditions of the adjustment process of the molybdenum-containing aqueous solution so far.
  • the average particle diameter, aspect ratio, apparent density, fluidity, and yield of the molybdenum granulated powder obtained by the production methods of Examples 1A to 7A and Comparative Examples 2 to 3 were investigated.
  • the average particle diameter extracted arbitrary 100 grains of the obtained molybdenum granulated powder took the enlarged photograph, calculated
  • the yield was calculated from the ratio of (the total amount of the granulated powder / 40 kg) ⁇ 100% of the amount of the molybdenum powder 40 kg and the total amount of the granulated molybdenum powder.
  • the measurement results are shown in Table 4 below.
  • the molybdenum granulated powder produced by the method for producing molybdenum granulated powder according to this example has a small deviation from the target average particle diameter B, and has an aspect ratio and an apparent appearance. The density and fluidity were excellent. In addition, it can be said that this is an efficient manufacturing method with a high yield.
  • Comparative Example 2 and Comparative Example 3 in which A / B is outside the range of the present invention showed characteristics in which both parameters deteriorated.
  • Container Container for preparing molybdenum-containing aqueous solution
  • Container Container for preparing molybdenum-containing aqueous solution
  • Molybdenum powder Molybdenum powder with added dopant
  • Binder 5 ... Water to be recharged as required 6
  • Molybdenum-containing aqueous solution 7 ...
  • Molybdenum-containing aqueous solution inlet 8 ...
  • Rotary plate 9 ... Molybdenum granulated powder 10 ... Outer wall 11 of spray dryer ... Recovery of molybdenum granulated powder container

Abstract

This method for producing a molybdenum granulated powder is characterized by comprising: a step in which water is injected into a container, and the water is heated to 50 to 80°C; a step in which a binder is added to the heated water; a step in which an aqueous solution containing molybdenum is prepared by loading molybdenum powder with an average particle size of 1 to 10 μm, to which at least one of a potassium component, an aluminum component and a silicon component has been added, while stirring the water; and a step in which the aqueous solution containing molybdenum is loaded in a spray dryer in which, when the rotation speed of a rotator of the spray dryer in which the aqueous solution containing molybdenum is to be dispersed, is regarded as A (rpm), and the average particle size of the granulated powder is regarded as B (μm), A/B ranges from 50 to 700, and the aqueous solution containing molybdenum is dispersed and dried to prepare the molybdenum granulated powder. The abovementioned method enables a doped molybdenum granulated powder having the intended average particle size to be produced at a high yield.

Description

モリブデン造粒粉の製造方法およびモリブデン造粒粉Method for producing molybdenum granulated powder and molybdenum granulated powder
　本発明は、モリブデン造粒粉の製造方法およびモリブデン造粒粉に関する。 The present invention relates to a method for producing molybdenum granulated powder and molybdenum granulated powder.
　モリブデン（Ｍｏ）は、融点が２６２０℃と高いことから耐熱材料として様々な分野に用いられている。例えば、溶射用材料、焼結炉用板材、電極部品、マグネトロン用ステム、スパッタリングターゲットなどに適用されている。溶射用材料は、Ｍｏ粉末やＭｏロッドの状態で原料として供給する方法がある。また、板材は、焼結で製造する場合や、圧延と鍛造とを組合せて製造する場合がある。また、電極部品などは板材を加工する場合、線引き加工してワイヤ加工される場合や焼結法によって製造される場合がある。
　このようにＭｏを使用する場合、（１）Ｍｏを粉末のまま使用する方法、（２）Ｍｏを焼結した焼結体として使用する場合、（３）圧延、鍛造、鋳造などにより板状に加工する方法、（４）線引き加工してワイヤとして使用する方法、など、様々な使用方法がある。
　上記いずれの使用方法であっても、Ｍｏ粉末かＭｏ溶湯を初期原料として用いることになる。Ｍｏ溶湯は、原材料を溶解し鋳造して目的の形状に加工する方法で使用される。Ｍｏ溶湯を使用する方法は、金型に溶湯を流し込む方法であるため、比較的に単純で、かつ大きな形状に加工することができる方法である。
　一方、Ｍｏは、前述の通り、高融点金属であるため、Ｍｏ溶湯の管理を確実に行うためには、耐熱性が高い大型設備が必要である。また、Ｍｏ溶湯を鋳型に流し込む方法であるため、複雑な形状には対応できない。
　このため、一般的には、Ｍｏ粉末を焼結してＭｏ焼結体として使用する方法が採用されている。焼結法であれば、金型にＭｏ粉末を詰めることにより、複雑な形状を有する部品も作製可能である。例えば、特許第４１５７３６９号公報（特許文献１）では、断面がコの字状（カップ形状）である冷陰極管用焼結電極が開示されている。特許文献１では焼結法を用いて、直径が１～２ｍｍ程度のカップ形状の電極を作製している。
　焼結法により、焼結体を作製する場合、Ｍｏ粉末に対して造粒工程、成形工程、脱脂工程、焼結工程などが実施される。これまで、焼結法では脱脂工程や焼結工程の改良を中心として進められてきた。特許文献１の［００２７］段落では、脱脂工程をウエット水素雰囲気で行う一方、焼結工程を水素雰囲気で行うことが開示されている。これにより焼結性が向上し、製造歩留りの向上が図られる。
　また、国際公開ＷＯ２０１１／００４８８７Ａ１のパンフレット（特許文献２）では、平均粒径が０．５～１００μｍである高純度モリブデン粉末の製造方法が開示されている。特許文献２では、１次粒子の割合が５０％以上であるモリブデン粉末が開示されている。　
　これまでのＭｏ焼結法においても、Ｍｏ原料粉末、脱脂工程および焼結工程に関しての改良が進められていた。しかしながら、その製造歩留りは必ずしも１００％には到達するものではなかった。このような現象は、カリウム等のドープ剤を添加したＭｏ粉末を使ったＭｏ焼結体に関しても同様に起きていた。 Molybdenum (Mo) is used in various fields as a heat resistant material because it has a high melting point of 2620 ° C. For example, it is applied to thermal spray materials, sintering furnace plate materials, electrode parts, magnetron stems, sputtering targets, and the like. There is a method of supplying the material for thermal spraying as a raw material in the state of Mo powder or Mo rod. Further, the plate material may be manufactured by sintering, or may be manufactured by combining rolling and forging. Further, electrode parts and the like may be manufactured by processing a plate material, drawing a wire by wire drawing, or manufacturing by a sintering method.
When using Mo in this way, (1) a method of using Mo as a powder, (2) when using Mo as a sintered body, (3) plate-like by rolling, forging, casting, etc. There are various methods of use, such as a method of processing, and (4) a method of drawing and using as a wire.
In any of the above usage methods, Mo powder or molten Mo is used as the initial raw material. Mo molten metal is used by a method in which raw materials are melted and cast into a desired shape. The method using the molten Mo is a method in which the molten metal is poured into a mold, and is a relatively simple method that can be processed into a large shape.
On the other hand, Mo is a refractory metal as described above, and therefore large equipment with high heat resistance is required to reliably manage the molten Mo. Moreover, since it is the method of pouring molten Mo into a casting_mold | template, it cannot respond to a complicated shape.
For this reason, the method of sintering Mo powder and using it as a Mo sintered body is generally employed. If it is a sintering method, the component which has a complicated shape is also producible by packing Mo powder in a metal mold | die. For example, Japanese Patent No. 4157369 (Patent Document 1) discloses a sintered electrode for a cold cathode tube having a U-shaped cross section (cup shape). In Patent Document 1, a cup-shaped electrode having a diameter of about 1 to 2 mm is manufactured using a sintering method.
When producing a sintered compact by a sintering method, a granulation process, a shaping | molding process, a degreasing process, a sintering process, etc. are implemented with respect to Mo powder. Until now, the sintering method has been progressed mainly by improving the degreasing process and the sintering process. In paragraph [0027] of Patent Document 1, it is disclosed that the degreasing step is performed in a wet hydrogen atmosphere while the sintering step is performed in a hydrogen atmosphere. As a result, the sinterability is improved and the production yield is improved.
Further, a pamphlet (Patent Document 2) of International Publication WO2011 / 004887A1 discloses a method for producing high-purity molybdenum powder having an average particle size of 0.5 to 100 μm. Patent Document 2 discloses a molybdenum powder in which the proportion of primary particles is 50% or more.
In the Mo sintering method so far, improvements have been made on the Mo raw material powder, the degreasing process, and the sintering process. However, the production yield did not necessarily reach 100%. Such a phenomenon also occurred in the same way for a Mo sintered body using Mo powder to which a dopant such as potassium was added.
特許第４１５７３６９号公報Japanese Patent No. 4157369 国際公開ＷＯ２０１１／００４８８７Ａ１のパンフレットPamphlet of International Publication WO2011 / 004887A1
　本発明者らは、ドープ剤を添加したＭｏ粉末を初期原料として使用した製品の歩留りが向上しない原因を追究した。その結果、Ｍｏ造粒粉のサイズ、密度、流動性などのばらつきが大きいために、成形工程での充填密度や供給量のばらつきを生じ、製品歩留りが低下する原因となることが判明した。また、溶射粉としてＭｏ造粒粉を使う場合には、溶射フレーム炎への供給量のばらつきが生じ、溶射膜としての特性が安定しないなどの問題が発生していた。この原因を追及したところ、造粒工程において目的とする造粒粉の平均粒径に応じた管理がなされていないことに原因があることを見出した。
　本発明は、このような問題を解決するためになされたものであり、Ｍｏ製品（粉末または焼結体）の品質の安定化や歩留りの向上を実現できるモリブデン造粒粉の製造方法を提供することを目的とする。 The present inventors have investigated the reason why the yield of a product using Mo powder added with a dopant as an initial raw material is not improved. As a result, it was found that the variation in the size, density, fluidity, etc. of the Mo granulated powder caused a variation in the filling density and supply amount in the molding process, which caused the product yield to decrease. In addition, when Mo granulated powder is used as the thermal spray powder, there is a problem that the supply amount to the thermal spray flame varies and the characteristics as the thermal spray film are not stable. As a result of pursuing this cause, it was found that there was a cause that the management according to the average particle size of the intended granulated powder was not performed in the granulation step.
The present invention has been made to solve such problems, and provides a method for producing molybdenum granulated powder capable of stabilizing the quality of Mo products (powder or sintered body) and improving the yield. For the purpose.
　本発明の実施形態に係るモリブデン造粒粉の製造方法は、容器に水を注入し、水を５０～８０℃に加熱する工程と、加熱された水にバインダーを添加する工程と、上記水を攪拌しながら、カリウム成分、アルミニウム成分およびケイ素成分の少なくとも１種を添加した平均粒径１～１０μｍのモリブデン粉末を投入することによりモリブデン含有水溶液を調製する工程と、上記モリブデン含有水溶液を分散するスプレードライヤーの回転板の回転数をＡ（ｒｐｍ）とし、造粒粉の平均粒径をＢ（μｍ）としたときに、Ａ／Ｂが５０～７００の範囲であるスプレードライヤーに上記モリブデン含有水溶液を投入し、上記モリブデン含有水溶液を分散すると共に乾燥してモリブデン造粒粉を調製する工程と、を有することを特徴とするものである。
　また、スプレードライヤーによる工程完了後の造粒粉に対して、平均粒径Ｂの２～３倍のメッシュ径を有する篩を通す篩分け工程をさらに実施することが好ましい。また、モリブデン造粒粉の平均粒径Ｂが２０～１５０μｍであることが好ましい。また、スプレードライヤーの回転板の回転数Ａが５０００～１６０００ｒｐｍであることが好ましい。
　また、カリウム成分は、カリウム元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることが好ましい。また、アルミニウム成分は、アルミニウム元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることが好ましい。また、ケイ素成分は、ケイ素元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることが好ましい。
　また、バインダーがポリビニルアルコール粉末、ポリエチンレングリコール粉末およびカルボメキシメチルセルロース粉末の少なくとも１種であることが好ましい。また、投入するモリブデン粉末の合計量を１００体積部にしたときに、バインダーの体積を３～２０体積部とすることが好ましい。また、得られるモリブデン造粒粉の見かけ密度が１．３～３．０ｇ／ｃｃであることが好ましい。
　また、モリブデン含有水溶液は、モリブデン粉末量を１００質量部としたときに、純水量が０．２～１リットルであることが好ましい。また、スプレードライヤーは、１５０～３００℃の熱風を供給しながらモリブデン造粒粉の乾燥を実施することが好ましい。また、スプレードライヤーは大気圧以下の減圧雰囲気でモリブデン造粒粉の乾燥を実施することが好ましい。また、得られた造粒粉の流動性が５０ｓｅｃ／５０ｇ以下であることが好ましい。
　また、本発明のモリブデン造粒粉は、カリウム成分、アルミニウム成分およびケイ素成分の少なくとも１種を含み、見かけ密度が１．３～３．０ｇ／ｃｃであることを特徴とするものである。
　また、モリブデン造粒粉の平均粒径が２０～１５０μｍであることが好ましい。また、モリブデン粉末の合計量を１００体積部にしたときに、バインダーの体積が３～２０体積部であることが好ましい。また、モリブデン造粒粉の流動性が５０ｓｅｃ／５０ｇ以下であることが好ましい。 A method for producing molybdenum granulated powder according to an embodiment of the present invention includes a step of injecting water into a container and heating the water to 50 to 80 ° C., a step of adding a binder to the heated water, A step of preparing a molybdenum-containing aqueous solution by adding a molybdenum powder having an average particle diameter of 1 to 10 μm to which at least one of a potassium component, an aluminum component and a silicon component is added while stirring, and a spray for dispersing the molybdenum-containing aqueous solution. When the rotational speed of the rotating plate of the dryer is A (rpm) and the average particle size of the granulated powder is B (μm), the molybdenum-containing aqueous solution is applied to the spray dryer in which A / B is in the range of 50 to 700. And a step of preparing a molybdenum granulated powder by dispersing and drying the molybdenum-containing aqueous solution.
Further, it is preferable to further carry out a sieving step of passing a sieve having a mesh size 2 to 3 times the average particle size B to the granulated powder after completion of the step by the spray dryer. The average particle diameter B of the molybdenum granulated powder is preferably 20 to 150 μm. Further, the rotational speed A of the rotating plate of the spray dryer is preferably 5000 to 16000 rpm.
The potassium component is preferably added in the range of 100 to 1000 ppm by mass in terms of a potassium element simple substance. The aluminum component is preferably added in the range of 100 to 1000 ppm by mass in terms of a single aluminum element. The silicon component is preferably added in the range of 100 to 1000 ppm by mass in terms of silicon element.
In addition, the binder is preferably at least one of polyvinyl alcohol powder, polyethylene glycol powder and carbomethyl methylcellulose powder. In addition, when the total amount of molybdenum powder to be added is 100 parts by volume, the volume of the binder is preferably 3 to 20 parts by volume. The apparent density of the resulting molybdenum granulated powder is preferably 1.3 to 3.0 g / cc.
The molybdenum-containing aqueous solution preferably has a pure water amount of 0.2 to 1 liter when the amount of molybdenum powder is 100 parts by mass. The spray dryer preferably dries the molybdenum granulated powder while supplying hot air of 150 to 300 ° C. Moreover, it is preferable that the spray dryer performs drying of the molybdenum granulated powder in a reduced-pressure atmosphere of atmospheric pressure or lower. Moreover, it is preferable that the fluidity of the obtained granulated powder is 50 sec / 50 g or less.
The molybdenum granulated powder of the present invention is characterized in that it contains at least one of a potassium component, an aluminum component, and a silicon component and has an apparent density of 1.3 to 3.0 g / cc.
The average particle diameter of the molybdenum granulated powder is preferably 20 to 150 μm. Further, when the total amount of molybdenum powder is 100 parts by volume, the volume of the binder is preferably 3 to 20 parts by volume. Further, the fluidity of the molybdenum granulated powder is preferably 50 sec / 50 g or less.
　本発明に係るモリブデン造粒粉の製造方法によれば、造粒工程において、水を所定温度に温めて攪拌しながら、ドープ剤添加モリブデン粉末およびバインダーを供給し、さらに目的とする造粒粉の平均粒径とスプレードライヤーの回転速度を所定範囲に制御していることから、平均粒径、見かけ密度および流動性が優れたモリブデン造粒粉を製造することができる。 According to the method for producing molybdenum granulated powder according to the present invention, in the granulation step, while adding water to a predetermined temperature and stirring, supplying the dopant-added molybdenum powder and binder, Since the average particle diameter and the rotational speed of the spray dryer are controlled within a predetermined range, molybdenum granulated powder having excellent average particle diameter, apparent density and fluidity can be produced.
本発明方法で使用するモリブデン含有水溶液を調製する工程の一例を示す断面図である。It is sectional drawing which shows an example of the process of preparing the molybdenum containing aqueous solution used with the method of this invention. 本発明方法で使用するスプレードライヤーにモリブデン含有水溶液を投入する工程の一例を示す断面図である。It is sectional drawing which shows an example of the process of throwing in molybdenum containing aqueous solution to the spray dryer used by the method of this invention. 本発明に係るモリブデン造粒粉の形状例を示す正面図である。It is a front view which shows the example of a shape of the molybdenum granulated powder which concerns on this invention.
　本発明の実施形態に係るモリブデン造粒粉の製造方法は、容器に水を注入し、水を５０～８０℃に加熱する工程と、加熱された水にバインダーを添加する工程と、上記水を攪拌しながら、カリウム成分、アルミニウム成分およびケイ素成分の少なくとも１種を添加した平均粒径１～１０μｍのモリブデン粉末を投入することによりモリブデン含有水溶液を調製する工程と、上記モリブデン含有水溶液を分散するスプレードライヤーの回転板の回転数をＡ（ｒｐｍ）とし、造粒粉の平均粒径をＢ（μｍ）としたときに、Ａ／Ｂが５０～７００の範囲であるスプレードライヤーに上記モリブデン含有水溶液を投入し、上記モリブデン含有水溶液を分散すると共に乾燥してモリブデン造粒粉を調製する工程と、を有することを特徴とするものである。 A method for producing molybdenum granulated powder according to an embodiment of the present invention includes a step of injecting water into a container and heating the water to 50 to 80 ° C., a step of adding a binder to the heated water, A step of preparing a molybdenum-containing aqueous solution by adding molybdenum powder having an average particle diameter of 1 to 10 μm to which at least one of a potassium component, an aluminum component, and a silicon component is added while stirring, and a spray for dispersing the molybdenum-containing aqueous solution. When the rotational speed of the rotating plate of the dryer is A (rpm) and the average particle size of the granulated powder is B (μm), the molybdenum-containing aqueous solution is applied to the spray dryer in which A / B is in the range of 50 to 700. And a step of dispersing and drying the molybdenum-containing aqueous solution and preparing a molybdenum granulated powder. .
　図１に、モリブデン含有水溶液を調製する工程の一例を示す。図中、符号１は容器（モリブデン含有水溶液を調製するための容器）であり、２は水であり、３はモリブデン粉末（ドープ剤含有モリブデン粉末）であり、４はバインダーであり、５は必要に応じて再度投入する水であり、６はモリブデン含有水溶液、である。
　まず、容器に水を注入する。この水としては、水道水、純水、超純水などが使用される。純水および超純水は、不純物をほとんど含まない水である。この中で純水は比抵抗が１０４Ω・ｃｍ（２５℃）以上のものを示し、超純水は比抵抗が１８×１０６Ω・ｃｍ（２５℃）以上のものを示す。純水および超純水としては、蒸留水、イオン交換水、ＲＯ（Ｒｅｖｅｒｓｅ　Ｏｓｍｏｓｉｓ：逆浸透膜）水などが挙げられる。得られるモリブデン造粒粉に不純物が混入することを防止したいときは、純水や超純水を使用することが好ましい。なお、超純水は、その調製が複雑でコストアップの要因となるので、純水を用いることが好ましい。また、不純物の混入を制御する必要がない場合は、水道水を使用することにより、コストメリットが高くなる。
　また、容器１に水を注入し、その水を５０～８０℃に加熱する工程を行う。水の温度が５０℃未満では、後述するバインダーを添加したときに、バインダーが水に溶解せずに固まってしまうために、均一なモリブデン含有水溶液を調製することが不可能になる。また、水温が８０℃を越えた場合には、水の蒸発が過量になり、水、バインダーおよびモリブデン粉末の配合割合が大きく変化してしまうおそれがある。そのため、水の加熱温度は５０～８０℃、さらには６０～７０℃であることが好ましい。 FIG. 1 shows an example of a process for preparing a molybdenum-containing aqueous solution. In the figure, reference numeral 1 is a container (a container for preparing a molybdenum-containing aqueous solution), 2 is water, 3 is molybdenum powder (dope-containing molybdenum powder), 4 is a binder, and 5 is necessary. And 6 is a molybdenum-containing aqueous solution.
First, water is poured into the container. As this water, tap water, pure water, ultrapure water, or the like is used. Pure water and ultrapure water are water that contains almost no impurities. Among these, pure water has a specific resistance of 10 4 Ω · cm (25 ° C.) or higher, and ultrapure water has a specific resistance of 18 × 10 6 Ω · cm (25 ° C.) or higher. Examples of pure water and ultrapure water include distilled water, ion exchange water, and RO (Reverse Osmosis) water. When it is desired to prevent impurities from being mixed into the resulting molybdenum granulated powder, it is preferable to use pure water or ultrapure water. In addition, since the preparation of ultrapure water is complicated and causes cost increase, it is preferable to use pure water. Further, when it is not necessary to control the mixing of impurities, the cost merit is increased by using tap water.
Further, a process of injecting water into the container 1 and heating the water to 50 to 80 ° C. is performed. When the temperature of the water is less than 50 ° C., when a binder described later is added, the binder is hardened without being dissolved in water, so that it is impossible to prepare a uniform molybdenum-containing aqueous solution. In addition, when the water temperature exceeds 80 ° C., the evaporation of water becomes excessive, and the blending ratio of water, binder and molybdenum powder may change greatly. Therefore, the heating temperature of water is preferably 50 to 80 ° C., more preferably 60 to 70 ° C.
　次に、所定の温度に加熱された水にバインダーを添加する工程を行う。バインダーの材質は特に限定されるものではないが、ポリビニルアルコール（ＰＶＡ）粉末、ポリエチンレングリコール（ＰＥＧ）粉末およびカルボメキシメチルセルロース（ＣＭＣ）粉末から選択される少なくとも１種であることが好ましい。ポリビニルアルコール、ポリエチンレングリコールおよびカルボメキシメチルセルロースは水溶性であることから水に溶解する。また、例えば、焼結工程にて焼失するので不純物として焼結体中に残存しないので好ましい。また、均一に水に溶解させるには、水を攪拌しながらバインダーを添加することが肝要である。
　次に、水を攪拌しながら平均粒径が１～１０μｍのモリブデン粉末を投入することによりモリブデン含有水溶液を調製する工程を実施する。モリブデン粉末の平均粒径とは、一次粒径の平均粒径である。ここではＦＳＳＳ法（フィッシャー法）により求めた値を平均粒径とする。モリブデン粉末の平均粒径が１μｍ未満では、Ｍｏ粉が過小で製造することが困難であり、コストアップの要因となる。
　一方、平均粒径が１０μｍを超えると、一次粒径が大きすぎて造粒粉の特性を安定させることが困難となる。そのため、モリブデン粉末の平均粒径は１～１０μｍ、さらには２～５μｍが好ましい。また、モリブデン粉末を一度に大量の粉末を投入するとモリブデン粉末が必要以上に凝集し易い。そこで少量ずつ、例えば０．５～２ｋｇずつ投入することが好ましい。 Next, a step of adding a binder to water heated to a predetermined temperature is performed. The material of the binder is not particularly limited, but is preferably at least one selected from polyvinyl alcohol (PVA) powder, polyethylene glycol (PEG) powder, and carbomethyl methylcellulose (CMC) powder. Polyvinyl alcohol, polyethylene glycol, and carbomethyl methylcellulose are soluble in water because they are water-soluble. Also, for example, it is preferable because it does not remain as an impurity in the sintered body because it burns away in the sintering step. Moreover, in order to make it melt | dissolve uniformly in water, it is important to add a binder, stirring water.
Next, a step of preparing a molybdenum-containing aqueous solution by introducing molybdenum powder having an average particle diameter of 1 to 10 μm while stirring water is performed. The average particle size of the molybdenum powder is the average particle size of the primary particle size. Here, the value obtained by the FSSS method (Fischer method) is defined as the average particle size. If the average particle diameter of the molybdenum powder is less than 1 μm, the Mo powder is too small to be manufactured, which causes an increase in cost.
On the other hand, if the average particle size exceeds 10 μm, the primary particle size is too large and it becomes difficult to stabilize the characteristics of the granulated powder. Therefore, the average particle diameter of the molybdenum powder is preferably 1 to 10 μm, more preferably 2 to 5 μm. In addition, when a large amount of molybdenum powder is added at once, the molybdenum powder tends to aggregate more than necessary. Therefore, it is preferable to add a small amount, for example, 0.5 to 2 kg.
　また、バインダーの全量が加熱した水に溶解したことを確認した後に、モリブデン粉末を添加することが好ましい。バインダーを粉末状態で添加すれば、溶解したか否かが肉眼で判別できる。なお、バインダーとしてポリビニルアルコール粉末を使ったときには、ポリビニルアルコール粉末が水に完全に溶解すると、モリブデン粉末を添加する前の水が半透明になる。バインダーが水に完全に溶解したか否かを判定し易くするためにも、バインダーを添加した後、モリブデン粉末を添加する順番であることが好ましい。ポリエチンレングリコールおよびカルボメキシメチルセルロースについても同様のことが言える。
　図１に示すように、水２に、モリブデン粉末３、バインダー４を添加して、モリブデン水溶液６を調製するに際して、投入するモリブデン粉末の合計量を１００体積部にしたときに、バインダーの体積を３～２０体積部とすることが好ましい。バインダーはモリブデン造粒粉を形成する際に、モリブデン粉末同士を接着する接着剤の役割を果たす。
　そのため、モリブデン粉末の合計量を１００体積部としたときに、バインダーの添加量が３体積部未満では、バインダー量が過少であり、均一な造粒粉が得られない恐れがある。また、バインダーの添加量が２０体積部を超えて過大になると、モリブデン粉末同士の隙間にバインダーが入りすぎて密度のばらつきが大きな造粒粉となってしまう。そのため、バインダーの添加量はモリブデン粉末１００体積部に対し、３～２０体積部に設定されるが、さらには５～１５体積部であることが好ましい。 Further, it is preferable to add the molybdenum powder after confirming that the entire amount of the binder is dissolved in heated water. If the binder is added in a powder state, it can be visually discriminated whether or not it has been dissolved. When polyvinyl alcohol powder is used as the binder, when the polyvinyl alcohol powder is completely dissolved in water, the water before adding the molybdenum powder becomes translucent. In order to make it easy to determine whether or not the binder is completely dissolved in water, it is preferable to add the molybdenum powder after the binder is added. The same is true for polyethylene glycol and carbomethyl methylcellulose.
As shown in FIG. 1, when preparing molybdenum aqueous solution 6 by adding molybdenum powder 3 and binder 4 to water 2, when the total amount of molybdenum powder to be added is 100 parts by volume, the volume of the binder is reduced. It is preferably 3 to 20 parts by volume. The binder serves as an adhesive that bonds the molybdenum powders together when forming the molybdenum granulated powder.
Therefore, when the total amount of molybdenum powder is 100 parts by volume, if the amount of binder added is less than 3 parts by volume, the amount of binder is too small and uniform granulated powder may not be obtained. Moreover, when the addition amount of a binder exceeds 20 volume parts and becomes excessive, a binder will enter too much into the clearance gap between molybdenum powders, and it will become a granulated powder with a large dispersion | variation in a density. Therefore, the addition amount of the binder is set to 3 to 20 parts by volume with respect to 100 parts by volume of the molybdenum powder, and more preferably 5 to 15 parts by volume.
　また、モリブデン含有水溶液は、モリブデン粉末量を１００質量部としたときに、水量が０．２～１リットルであることが好ましい。スプレードライヤーには、モリブデン含有水溶液で投入される。このとき、モリブデン粉末量１００質量部に対し、水量が０．２リットル未満では水の量が少なすぎてモリブデン含有水溶液の粘性が上がり、スプレードライヤーに安定供給し難い。また、水量が１リットルを超えると水の量が多すぎて、安定供給し難い。なお、水量が多いときは、攪拌しながら供給することにより安定供給する方法もある。このスプレードライヤーへのモリブデン含有水溶液の供給は、機械化して自動化することも可能である。 The molybdenum-containing aqueous solution preferably has a water content of 0.2 to 1 liter when the amount of molybdenum powder is 100 parts by mass. The spray dryer is charged with an aqueous solution containing molybdenum. At this time, if the amount of water is less than 0.2 liter with respect to 100 parts by mass of the molybdenum powder, the amount of water is too small and the viscosity of the molybdenum-containing aqueous solution increases, and it is difficult to stably supply it to the spray dryer. Moreover, when the amount of water exceeds 1 liter, the amount of water is too large and it is difficult to stably supply water. In addition, when there is much water quantity, there also exists the method of supplying stably by supplying with stirring. The supply of the molybdenum-containing aqueous solution to the spray dryer can be automated by mechanization.
　また、必要に応じて、水５を追加投入してもよい。水を５０～８０℃に加熱しているため、バインダーおよびモリブデン粉末を投入、混合している段階で水が蒸発して水量が大きく変わってしまう恐れもある。また、容器１として、容積が２０リットル以上である大きな容器を使用する場合、水量を最終的な量の３０～６０％でバインダーおよびモリブデン粉末と混合した後、残りの水量７０～４０％を追加投入してモリブデン粉末と水量とを調整する方法も可能である。バインダーが水に完全に溶解したか否かを目視により確認し易くするためにも水を追加投入する方法は有効である。 In addition, water 5 may be added as necessary. Since the water is heated to 50 to 80 ° C., there is a possibility that the amount of water may change greatly due to the evaporation of the water when the binder and the molybdenum powder are added and mixed. If a large container with a volume of 20 liters or more is used as the container 1, the remaining amount of water is added to 70 to 40% after mixing the amount of water with the binder and molybdenum powder at 30 to 60% of the final amount. It is possible to adjust the amount of molybdenum powder and water by adding it. In order to make it easy to visually confirm whether or not the binder is completely dissolved in water, a method of additionally adding water is effective.
　また、本発明のモリブデン粉末は、カリウム成分、アルミニウム成分およびケイ素成分の少なくとも１種を添加したモリブデン粉末である。カリウム成分、アルミニウム成分およびケイ素成分としては、それぞれ単体元素、酸化物、複合酸化物などの化合物が使用される。
　また、カリウム成分は、カリウム元素単体換算で１００～１０００質量ｐｐｍの範囲であることが好ましい。また、アルミニウム成分は、アルミニウム元素単体換算で１００～１０００質量ｐｐｍの範囲であることが好ましい。また、ケイ素成分は、ケイ素元素単体換算で１００～１０００質量ｐｐｍの範囲であることが好ましい。それぞれ１００質量ｐｐｍ未満では添加の効果が小さく、１０００質量ｐｐｍを超えると却って特性が低下する。また、ドープ剤は、１種であっても、２種以上を添加してもよい。
　また、カリウム成分、アルミニウム成分、ケイ素成分は、ドープ剤と呼ばれる成分である。これらドープ剤を添加することにより、高純度モリブデンと比較して、再結晶温度が高くなり、高温強度が高くなる。また、再結晶熱処理後に延性が向上することから、ワイヤへの線引き加工などの加工時の二次加工性が向上する。二次加工は、ワイヤへの線引き加工の他に、ワイヤの折り曲げ加工、板材（Ｍｏ焼結体からなる板材）の圧延加工、曲げ加工や打ち抜き加工などが挙げられる。また、ワイヤとした場合には、ノンサグ性、高温耐振性、耐黒化性の向上をも図ることができる。
　また、ドープ剤を添加したモリブデン粉末の製造方法は特に限定されるものではないが、次の方法が例示される。
　まず、モリブデン粉末の原料として、アンモニウムダイモリブデート（（ＮＨ４）２・Ｍｏ２Ｏ７））を用意し、水素気流中で温度６００～７５０℃で加熱し、Ｍｏ酸化物を得る。このＭｏ酸化物に珪酸カリウムをＭｏ元素単体当たりのカリウム元素単体量が１００～１０００質量ｐｐｍになるように添加する。このとき純水を加え、混練して、攪拌しながら１００～１４０℃に加熱して乾燥し、ドープ剤を添加したモリブデン酸化物粉末とする。ドープ剤添加モリブデン酸化物粉末を水素雰囲気中で１０００～１２００℃で２～５時間加熱し還元してドープ剤添加モリブデン粉末を得ることができる。
　なお、上記はドープ剤としてカリウムを添加した例を示したものである。ケイ素やアルミニウムをドープ剤として添加する場合は、それぞれケイ素単体またはケイ素化合物、アルミニウム単体またはアルミニウム化合物を添加する。また、上記カリウム成分として珪酸カリウムを用いたが、これに限定されるものではなく、他のカリウム化合物を用いてもよい。また、カリウム、アルミニウムおよびケイ素を２種以上添加する場合は、それぞれの元素または化合物を添加してドープ剤添加モリブデン粉末を得れば良い。
　ドープ剤添加モリブデン粉末の純度に関しては特に限定されるものではないが、Ｍｏとドープ剤との合計が９９質量％以上、さらには９９．９％質量以上であることが好ましい。モリブデン粉末の主な不純物は、Ｆｅ（鉄）、Ｃａ（カルシウム）、Ｍｇ（マグネシウム）が挙げられる。また、これ以外の不純物としては、Ｎｉ（ニッケル）、Ｎａ（ナトリウム）、Ｐｂ（鉛）、Ｂｉ（ビスマス）、Ｃｄ（カドミウム）、Ｃｕ（銅）、Ｍｎ（マンガン）、Ｓｎ（錫）が挙げられる。モリブデンの純度の測定は、Ｆｅ（鉄）、Ｃａ（カルシウム）、Ｍｇ（マグネシウム）、Ｎｉ（ニッケル）、Ｎａ（ナトリウム）、Ｐｂ（鉛）、Ｂｉ（ビスマス）、Ｃｄ（カドミウム）、Ｃｕ（銅）、Ｍｎ（マンガン）、Ｓｎ（錫）の合計量を１００質量％から差し引いて求めるものとする。また、それぞれの不純物量としてはＦｅ（鉄）は１０質量ｐｐｍ以下、Ｃａ（カルシウム）は３０質量ｐｐｍ以下、Ｍｇ（マグネシウム）は２０質量ｐｐｍ以下、Ｎｉ（ニッケル）は５０質量ｐｐｍ以下、Ｎａ（ナトリウム）は１０質量ｐｐｍ以下、Ｐｂ（鉛）は７０質量ｐｐｍ以下、Ｂｉ（ビスマス）は７０質量ｐｐｍ以下、Ｃｄ（カドミウム）は７０質量ｐｐｍ以下、Ｃｕ（銅）は７０質量ｐｐｍ以下、Ｍｎ（マンガン）は２０質量ｐｐｍ以下、Ｓｎ（錫）は３０質量ｐｐｍ以下であることが好ましい。
　また、上記金属不純物以外の不純物として酸素などのガス成分が挙げられる。酸素量は７質量％以下、窒素量は７質量％以下であることが好ましい。 The molybdenum powder of the present invention is a molybdenum powder to which at least one of a potassium component, an aluminum component, and a silicon component is added. As the potassium component, the aluminum component, and the silicon component, compounds such as single elements, oxides, and complex oxides are used, respectively.
Further, the potassium component is preferably in the range of 100 to 1000 mass ppm in terms of potassium element simple substance. In addition, the aluminum component is preferably in the range of 100 to 1000 ppm by mass in terms of a single aluminum element. Further, the silicon component is preferably in the range of 100 to 1000 ppm by mass in terms of a silicon element. If the amount is less than 100 ppm by mass, the effect of addition is small. Moreover, a dopant may be 1 type or may add 2 or more types.
Moreover, a potassium component, an aluminum component, and a silicon component are components called a dopant. By adding these dopants, the recrystallization temperature is increased and the high temperature strength is increased as compared with high purity molybdenum. Moreover, since ductility improves after recrystallization heat processing, the secondary workability at the time of processes, such as a drawing process to a wire, improves. Secondary processing includes wire bending processing, wire bending processing, plate material (plate material made of Mo sintered body) rolling processing, bending processing, punching processing, and the like. Further, when a wire is used, non-sag, high-temperature vibration resistance, and blackening resistance can be improved.
Moreover, although the manufacturing method of the molybdenum powder which added the dopant is not specifically limited, the following method is illustrated.
First, ammonium dimolybdate ((NH 4 ) 2 · Mo 2 O 7 )) is prepared as a raw material for molybdenum powder, and heated at a temperature of 600 to 750 ° C. in a hydrogen stream to obtain Mo oxide. Potassium silicate is added to the Mo oxide so that the amount of elemental potassium element per elemental Mo is 100 to 1000 ppm by mass. At this time, pure water is added, kneaded, heated to 100 to 140 ° C. with stirring and dried to obtain a molybdenum oxide powder to which a dopant is added. The dopant-added molybdenum oxide powder can be heated and reduced at 1000 to 1200 ° C. for 2 to 5 hours in a hydrogen atmosphere to obtain a dopant-added molybdenum powder.
The above shows an example in which potassium is added as a dopant. When silicon or aluminum is added as a dopant, silicon alone or a silicon compound, and aluminum alone or an aluminum compound are added, respectively. Moreover, although potassium silicate was used as the potassium component, the invention is not limited to this, and other potassium compounds may be used. Moreover, when adding 2 or more types of potassium, aluminum, and silicon, what is necessary is just to add each element or compound and to obtain a dopant addition molybdenum powder.
The purity of the dopant-added molybdenum powder is not particularly limited, but the total of Mo and the dopant is preferably 99% by mass or more, and more preferably 99.9% by mass or more. Main impurities of the molybdenum powder include Fe (iron), Ca (calcium), and Mg (magnesium). Other impurities include Ni (nickel), Na (sodium), Pb (lead), Bi (bismuth), Cd (cadmium), Cu (copper), Mn (manganese), and Sn (tin). It is done. The measurement of the purity of molybdenum is Fe (iron), Ca (calcium), Mg (magnesium), Ni (nickel), Na (sodium), Pb (lead), Bi (bismuth), Cd (cadmium), Cu (copper) ), Mn (manganese) and Sn (tin) are subtracted from 100% by mass. Moreover, as for each impurity amount, Fe (iron) is 10 mass ppm or less, Ca (calcium) is 30 mass ppm or less, Mg (magnesium) is 20 mass ppm or less, Ni (nickel) is 50 mass ppm or less, Na ( Sodium) is 10 mass ppm or less, Pb (lead) is 70 mass ppm or less, Bi (bismuth) is 70 mass ppm or less, Cd (cadmium) is 70 mass ppm or less, Cu (copper) is 70 mass ppm or less, Mn ( Manganese) is preferably 20 ppm by mass or less, and Sn (tin) is preferably 30 ppm by mass or less.
Moreover, gas components, such as oxygen, are mentioned as impurities other than the said metal impurity. The amount of oxygen is preferably 7% by mass or less, and the amount of nitrogen is preferably 7% by mass or less.
　次に、得られたモリブデン含有水溶液をスプレードライヤーに投入する工程を実施する。図２にスプレードライヤーによる造粒工程の一例を示す。図中、符号１はモリブデン含有水溶液を入れた容器であり、６はモリブデン含有水溶液であり、７はモリブデン含有水溶液の投入口であり、８はモリブデン含有水溶液６を細かい液滴に分散させる回転板であり、９はモリブデン造粒粉であり、１０はスプレードライヤーの外壁であり、１１はモリブデン造粒粉の回収容器である。
　前記工程にて調整されたモリブデン含有水溶液６を投入口７に流し込む。投入口７への投入速度は、１０～８０ｃｃ／分が好ましい。投入速度が１０ｃｃ／分未満では投入量が過少であり量産性が悪化する。一方、投入速度が８０ｃｃ／分を超えると投入量が過多になり、得られる造粒粉の特性にばらつきが生じる。 Next, the process of throwing the obtained molybdenum containing aqueous solution into a spray dryer is implemented. FIG. 2 shows an example of a granulation process using a spray dryer. In the figure, reference numeral 1 is a container containing a molybdenum-containing aqueous solution, 6 is a molybdenum-containing aqueous solution, 7 is an inlet for the molybdenum-containing aqueous solution, and 8 is a rotating plate that disperses the molybdenum-containing aqueous solution 6 into fine droplets. 9 is a granulated molybdenum powder, 10 is an outer wall of the spray dryer, and 11 is a recovery container for the molybdenum granulated powder.
The molybdenum-containing aqueous solution 6 adjusted in the above process is poured into the charging port 7. The charging speed to the charging port 7 is preferably 10 to 80 cc / min. When the input speed is less than 10 cc / min, the input amount is too small and the mass productivity is deteriorated. On the other hand, when the charging speed exceeds 80 cc / min, the charging amount becomes excessive, and the characteristics of the resulting granulated powder vary.
　次に、投入されたモリブデン含有水溶液６は、投入口７を経由して回転板８上に供給される。回転板８は一定の回転数で回転している。回転している回転板８にモリブデン含有水溶液６が供給されると、一定量ずつ弾かれ表面張力により、球状のモリブデン造粒粉９が形成される。モリブデン造粒粉９はスプレードライヤーの外壁１０に沿って落下しモリブデン造粒粉の回収容器１１に回収される。
　モリブデン造粒粉の平均粒径は、回転板の回転速度との関連性が高い。そこで本発明では回転板の回転速度をＡ（ｒｐｍ）とし、モリブデン造粒粉の平均粒径をＢ（μｍ）としたとき、Ａ／Ｂを５０～７００の範囲に制御することを特徴とするものである。モリブデン含有水溶液６を回転板８に供給したとき、回転板に一定量ずつ弾かれ、弾かれたモリブデン含有水溶液６は表面張力により球状のモリブデン造粒粉９になる。また、バインダーを添加していることからも均一なモリブデン造粒粉を製造することができる。 Next, the charged molybdenum-containing aqueous solution 6 is supplied onto the rotating plate 8 via the charging port 7. The rotating plate 8 rotates at a constant rotational speed. When the molybdenum-containing aqueous solution 6 is supplied to the rotating rotating plate 8, it is repelled by a certain amount, and spherical molybdenum granulated powder 9 is formed by surface tension. The molybdenum granulated powder 9 falls along the outer wall 10 of the spray dryer and is collected in a molybdenum granulated powder collection container 11.
The average particle diameter of the molybdenum granulated powder is highly related to the rotation speed of the rotating plate. Therefore, the present invention is characterized in that A / B is controlled in the range of 50 to 700, where A (rpm) is the rotational speed of the rotating plate and B (μm) is the average particle diameter of the molybdenum granulated powder. Is. When the molybdenum-containing aqueous solution 6 is supplied to the rotating plate 8, the molybdenum-containing aqueous solution 6 is repelled by a certain amount on the rotating plate and becomes spherical molybdenum granulated powder 9 due to surface tension. Moreover, uniform molybdenum granulated powder can be manufactured also from having added the binder.
　造粒粉の平均粒径Ｂに対する回転板の回転速度Ａの比であるＡ／Ｂが５０未満では、目的とする造粒粉の平均粒径に対して回転板の回転速度が不足しているため、目的とする造粒粉の平均粒径Ｂが得られない。また、Ａ／Ｂが５０未満の場合は、目的とする造粒粉の平均粒径Ｂに対して大きな平均粒径を有する造粒粉となる。
　一方、Ａ／Ｂが７００を超えると、目的とする造粒粉の平均粒径Ｂに対して回転板の回転速度Ａが速すぎるため、目的とする造粒粉の平均粒径Ｂが得られない。また、Ａ／Ｂが７００を超えると、目的とする造粒粉の平均粒径Ｂに対して、小さな平均粒径となる。
　上記Ａ／Ｂの値を５０～７００の範囲に制御することにより、目的とする造粒粉の平均粒径Ｂに対して±５０％の範囲内の平均粒径を有する造粒粉が得られる。例えば、目的とする造粒粉の平均粒径Ｂを５０μｍとしたとき、±５０％とは５０×０．５＝２５μｍから平均粒径が２５～７５μｍの造粒粉が得られることを意味している。なお、造粒粉の平均粒径は拡大写真を使用して、そこに写る造粒粉の最大径を粒径とし、造粒粉１００粒の平均値を造粒粉の平均粒径とする。 When A / B, which is the ratio of the rotational speed A of the rotating plate to the average particle diameter B of the granulated powder, is less than 50, the rotational speed of the rotating plate is insufficient with respect to the average particle diameter of the intended granulated powder. Therefore, the average particle size B of the intended granulated powder cannot be obtained. Moreover, when A / B is less than 50, it becomes a granulated powder having a larger average particle diameter than the average particle diameter B of the intended granulated powder.
On the other hand, when A / B exceeds 700, the rotation speed A of the rotating plate is too high with respect to the average particle diameter B of the intended granulated powder, and thus the average particle diameter B of the intended granulated powder is obtained. Absent. Moreover, when A / B exceeds 700, it becomes a small average particle diameter with respect to the average particle diameter B of the intended granulated powder.
By controlling the value of A / B in the range of 50 to 700, a granulated powder having an average particle diameter within a range of ± 50% with respect to the average particle diameter B of the intended granulated powder can be obtained. . For example, when the average particle size B of the intended granulated powder is 50 μm, ± 50% means that a granulated powder having an average particle size of 25 to 75 μm can be obtained from 50 × 0.5 = 25 μm. ing. In addition, the average particle diameter of granulated powder uses an enlarged photograph, and makes the maximum diameter of the granulated powder reflected there the particle diameter, and the average value of 100 granulated powder is the average particle diameter of the granulated powder.
　また、造粒粉の平均粒径Ｂは２０～１５０μｍであることが好ましい。造粒粉の平均粒径が２０～１５０μｍの範囲であれば、様々な用途に適用できる。また、回転板８の回転数Ａは５０００～１６０００ｒｐｍであることが好ましい。上記回転数Ａが５０００～１６０００ｒｐｍの範囲であれば、効率的に回転板８上でモリブデン含有水溶液６が効果的に弾かれ、目的とする平均粒径を有するモリブデン造粒粉が得易くなる。 The average particle size B of the granulated powder is preferably 20 to 150 μm. If the average particle diameter of the granulated powder is in the range of 20 to 150 μm, it can be applied to various applications. Further, the rotational speed A of the rotating plate 8 is preferably 5000 to 16000 rpm. When the rotational speed A is in the range of 5000 to 16000 rpm, the molybdenum-containing aqueous solution 6 is effectively repelled efficiently on the rotating plate 8, and molybdenum granulated powder having a target average particle diameter is easily obtained.
　また、スプレードライヤーは、１５０～３００℃の熱風を供給しながらモリブデン造粒粉の乾燥を実施することが好ましい。スプレードライヤーの外壁内に１５０～３００℃の熱風を供給し、モリブデン造粒粉の乾燥を実施することにより、造粒粉中の水分を蒸発させ、バインダーによるモリブデン粉末同士の結合力を強化することができる。その結果、目的とする平均粒径を有するモリブデン造粒粉を効果的に製造することができる。
　熱風は図示しない熱風供給口からスプレードライヤーの外壁１０内に供給され、図示しない排気口から排気される。熱風を供給口から排気口に排気しながら供給することにより、常に新鮮な熱風を供給することが可能になり、造粒粉から蒸発した水分が他の造粒粉に取り込まれるのを防止することができる。なお、熱風の供給温度が１５０℃未満では水分の蒸発速度が遅い一方、３００℃を超えると、水分が瞬間的に蒸発し過ぎて造粒粉の粒径のばらつきが発生する原因となる。
　また、スプレードライヤーは、大気圧以下の減圧雰囲気でモリブデン造粒粉の乾燥を実施することが好ましい。スプレードライヤーの外壁１０内を大気圧以下の減圧雰囲気とすることにより、造粒粉中の水分を蒸発し易くすることができる。なお、減圧雰囲気は、大気圧（１ａｔｍ＝１．０１×１０５Ｐａ）から１００～５００Ｐａ低い減圧雰囲気であることが好ましい。１００Ｐａ未満では減圧雰囲気とする効果が十分でない一方、５００Ｐａを超えると減圧雰囲気を制御する負担が大きくなりコストアップの要因となる。 The spray dryer preferably dries the molybdenum granulated powder while supplying hot air of 150 to 300 ° C. Supplying hot air of 150-300 ° C into the outer wall of the spray dryer to dry the molybdenum granulated powder, thereby evaporating the moisture in the granulated powder and strengthening the bonding force between the molybdenum powders by the binder Can do. As a result, it is possible to effectively produce molybdenum granulated powder having a target average particle diameter.
Hot air is supplied into the outer wall 10 of the spray dryer from a hot air supply port (not shown) and exhausted from an exhaust port (not shown). By supplying hot air while exhausting it from the supply port to the exhaust port, it becomes possible to always supply fresh hot air and prevent moisture evaporated from the granulated powder from being taken into other granulated powder. Can do. When the supply temperature of hot air is less than 150 ° C., the evaporation rate of water is slow. On the other hand, when it exceeds 300 ° C., moisture instantaneously evaporates and causes variation in the particle size of the granulated powder.
Moreover, it is preferable that the spray drier carries out the drying of the molybdenum granulated powder in a reduced-pressure atmosphere below atmospheric pressure. By setting the inside of the outer wall 10 of the spray dryer to a reduced-pressure atmosphere of atmospheric pressure or less, moisture in the granulated powder can be easily evaporated. The reduced-pressure atmosphere is preferably a reduced-pressure atmosphere that is 100 to 500 Pa lower than atmospheric pressure (1 atm = 1.01 × 10 5 Pa). If the pressure is less than 100 Pa, the effect of reducing the reduced pressure atmosphere is not sufficient.
　本発明に係るモリブデン造粒粉の製造方法によれば、造粒粉の平均粒径に合わせてスプレードライヤーの回転板の回転速度を調整していることから、目的とする平均粒径に対し±５０％の範囲内の造粒粉を得ることができる。
　また、得られるモリブデン造粒粉の見かけ密度が１．３～３．０ｇ／ｃｃであることが好ましい。前述のように本発明ではモリブデン造粒粉の平均粒径は拡大写真を使用して測定している。この測定方法であれば、外観上の平均粒径は判断できる。
　しかしながら、造粒粉の内部に空隙が多く密度が小さな造粒粉が存在すると、その後の製品（溶射用粉末や焼結体）に使用するときに、部分的にモリブデン粉末の存在比率にばらつきが生じる。存在比率のばらつきは、製品のばらつきに繋がる。
　例えば、造粒粉を溶射用粉末に使用する場合、密度が大きく異なる造粒粉が存在すると、溶射フレーム炎に投入されるモリブデン粉末量にばらつきが生じ、結果として溶射Ｍｏ膜の特性にばらつきが発生する原因となる。また、焼結体を作製する場合は、成形金型に挿入されるモリブデン量のばらつきが生じ、焼結体中のポアが必要以上に大きくなる恐れがある。
　モリブデン造粒粉の見かけ密度が１．３ｇ／ｃｃ未満であると、造粒粉中のモリブデン量が過少であり、その後の製品化において品質のばらつきを生じる原因となる。一方、見かけ密度が３．０ｇ／ｃｃを超えて過大になると、モリブデン粉末がぎっしり詰まった状態になるため、スプレードライヤーで安定的に製造することが困難である。見かけ密度の測定方法は、ＪＩＳ－Ｚ－２５０４に準拠した測定方法で行うものとする。 According to the method for producing molybdenum granulated powder according to the present invention, since the rotation speed of the rotating plate of the spray dryer is adjusted in accordance with the average particle diameter of the granulated powder, ± Granulated powder in the range of 50% can be obtained.
The apparent density of the resulting molybdenum granulated powder is preferably 1.3 to 3.0 g / cc. As described above, in the present invention, the average particle diameter of the molybdenum granulated powder is measured using an enlarged photograph. If it is this measuring method, the average particle diameter on an external appearance can be judged.
However, if granulated powder with many voids and low density is present inside the granulated powder, when it is used for subsequent products (spraying powder or sintered body), the abundance ratio of the molybdenum powder partially varies. Arise. Variation in the existence ratio leads to variation in the product.
For example, when granulated powder is used as a thermal spraying powder, if there are granulated powders with significantly different densities, the amount of molybdenum powder charged into the thermal flame flame will vary, resulting in variations in the characteristics of the thermal sprayed Mo film. Cause it to occur. Moreover, when producing a sintered compact, the variation in the amount of molybdenum inserted into the molding die occurs, and the pores in the sintered compact may become larger than necessary.
If the apparent density of the molybdenum granulated powder is less than 1.3 g / cc, the amount of molybdenum in the granulated powder is too small, and this causes a variation in quality in the subsequent commercialization. On the other hand, when the apparent density exceeds 3.0 g / cc, the molybdenum powder is tightly packed, and it is difficult to stably manufacture with a spray dryer. The apparent density is measured by a measuring method based on JIS-Z-2504.
　また、得られた造粒粉の流動性が５０ｓｅｃ／５０ｇ以下であることが好ましい。上記流動性の測定もＪＩＳ－Ｚ－２５０４に準拠した測定方法で実施するものとする。ここで流動性とは、造粒粉がどれだけ円滑に移動する（流れる）かを示す指標である。流動性が良い（流動性５０ｓｅｃ／５０ｇ以下）と、製品化する際の成形金型への供給が円滑迅速に実施できるのである。つまりは、取扱い性が良好な造粒粉であると言える。
　また、流動性が良好であるということは、造粒粉の形状が球体に近いことを意味している。造粒粉が球体に近いとは、アスペクト比が１．５以下を示すものとする。図３にモリブデン造粒粉の形状例を示す。図中、符号３はモリブデン粉末であり、９はモリブデン造粒粉であり、Ｌ１はモリブデン造粒粉の短径であり、Ｌ２は長径である。アスペクト比は「長径Ｌ２／短径Ｌ１」により求める。アスペクト比が１．０とは真球に近い状態であることを示す。 Moreover, it is preferable that the fluidity of the obtained granulated powder is 50 sec / 50 g or less. The fluidity is measured by a measuring method based on JIS-Z-2504. Here, the fluidity is an index indicating how smoothly the granulated powder moves (flows). When the fluidity is good (fluidity 50 sec / 50 g or less), the supply to the molding die at the time of commercialization can be carried out smoothly and rapidly. In other words, it can be said that the granulated powder has good handleability.
Moreover, that fluidity | liquidity is favorable means that the shape of granulated powder is close to a sphere. When the granulated powder is close to a sphere, the aspect ratio is 1.5 or less. FIG. 3 shows an example of the shape of molybdenum granulated powder. In the figure, reference numeral 3 denotes molybdenum powder, 9 denotes molybdenum granulated powder, L1 denotes a short diameter of the molybdenum granulated powder, and L2 denotes a long diameter. The aspect ratio is obtained by “major axis L2 / minor axis L1”. An aspect ratio of 1.0 indicates a state close to a true sphere.
　このように本発明のモリブデン造粒粉の製造方法よれば、平均粒径、見かけ密度、流動性が優れたモリブデン造粒粉を、高い歩留りで効率良く製造することができる。
　また、モリブデン造粒粉の平均粒径、特に粒度分布の制御工程として、スプレードライヤーによる造粒工程完了後の造粒粉に対して、平均粒径Ｂの２～３倍のメッシュ径を有する篩を通す篩分け工程を実施する方法も効果的である。上記篩分け工程を実施することにより、過大な造粒粉を除去することができる。これにより、さらに平均粒径の制御が可能となる。また、上記篩分け工程により、過小な造粒粉を除去することも有効である。
　以上のように本発明のモリブデン造粒粉の製造方法によれば、平均粒径、見かけ密度、流動性が優れたモリブデン造粒粉を高い歩留りで効率良く製造することができる。そのため、各製品に応じた造粒粉を歩留り良く製造することができる。
　造粒粉の用途としては、溶射用粉末、各種焼結体の原料粉などが挙げられる。溶射用粉末として、平均粒径、見かけ密度および流動性が優れたモリブデン造粒粉を使用することにより溶射フレーム炎への供給量を安定化させることができる。その結果、溶射膜の品質を均質なものとすることができる。
　また、各種焼結体の原料粉末としてモリブデン造粒粉を使う場合、平均粒径、見かけ密度および流動性が優れたモリブデン造粒粉を使うことにより、成形金型への充填量を均質化できる。その結果、焼結体の密度などを安定化させることができる。特に、成形金型の形状に応じて、平均粒径を変化させることにより、さらに製造歩留りの向上を図ることができる。例えば、厚さが１ｍｍ以下である焼結体では造粒粉の平均粒径を５０μｍ程度とし、厚さが５ｍｍ程度の焼結体では、造粒粉の平均粒径を１００μｍ程度にすることにより成形金型への充填を効率よく実施することができる。 Thus, according to the manufacturing method of the molybdenum granulated powder of this invention, the molybdenum granulated powder excellent in average particle diameter, apparent density, and fluidity | liquidity can be efficiently manufactured with a high yield.
In addition, as a process for controlling the average particle diameter of the molybdenum granulated powder, especially the particle size distribution, a sieve having a mesh diameter 2 to 3 times the average particle diameter B of the granulated powder after completion of the granulation process by a spray dryer. A method of carrying out a sieving step is also effective. Excessive granulated powder can be removed by carrying out the sieving step. As a result, the average particle diameter can be further controlled. It is also effective to remove excessive granulated powder by the sieving step.
As described above, according to the method for producing molybdenum granulated powder of the present invention, molybdenum granulated powder having excellent average particle diameter, apparent density, and fluidity can be efficiently produced with high yield. Therefore, the granulated powder according to each product can be manufactured with a good yield.
Examples of the use of the granulated powder include thermal spraying powder, raw powders of various sintered bodies, and the like. By using molybdenum granulated powder having excellent average particle diameter, apparent density, and fluidity as the thermal spraying powder, the supply amount to the thermal spray flame can be stabilized. As a result, the quality of the sprayed film can be made uniform.
In addition, when using molybdenum granulated powder as a raw material powder for various sintered bodies, it is possible to homogenize the filling amount into the molding die by using molybdenum granulated powder with excellent average particle diameter, apparent density and fluidity. . As a result, the density of the sintered body can be stabilized. In particular, the production yield can be further improved by changing the average particle size according to the shape of the molding die. For example, in a sintered body having a thickness of 1 mm or less, the average particle diameter of the granulated powder is about 50 μm, and in a sintered body having a thickness of about 5 mm, the average particle diameter of the granulated powder is about 100 μm. It is possible to efficiently fill the molding die.
（実施例）
（実施例１～７および比較例１）
　表１に示すドープ剤添加モリブデン粉末と、バインダーとしてポリビニルアルコール（ＰＶＡ）粉末および純水を用意した。ステンレス製容器に、水を注入し、水を加熱および攪拌しながら、ポリビニルアルコール粉末を添加し、添加したポリビニルアルコール粉末を全て溶解させた。ポリビニルアルコール粉末が全て溶解したときは、半透明の水溶液となっていることが確認できた。その後、モリブデン粉末を１～２ｋｇずつ、合計４０ｋｇ投入した。モリブデン粉末の攪拌に際して、水が蒸発して不足する分は、必要に応じて純水を追加投入した。バインダーとしてポリビニルアルコール粉末を使用した試料を実施例１～５とした。また、バインダーとしてポリエチンレングリコール粉末を使用した試料を実施例６、カルボメキシメチルセルロース粉末を使用した試料を実施例７とした。一方、水の加熱温度を３５℃とした点以外は実施例1と同様に処理して比較例１に係るモリブデン含有水溶液を調製した。
　ここまでのモリブデン含有水溶液の調整工程の条件を下記表２に示す。 (Example)
(Examples 1 to 7 and Comparative Example 1)
A dopant-added molybdenum powder shown in Table 1 and polyvinyl alcohol (PVA) powder and pure water were prepared as binders. Water was poured into a stainless steel container, and while the water was heated and stirred, the polyvinyl alcohol powder was added and all the added polyvinyl alcohol powder was dissolved. When all the polyvinyl alcohol powder was dissolved, it was confirmed that the solution was a translucent aqueous solution. Thereafter, a total of 40 kg of molybdenum powder was added in an amount of 1-2 kg. When the molybdenum powder was agitated, pure water was added as needed for the amount of water that was insufficient due to evaporation. Samples using polyvinyl alcohol powder as a binder were designated as Examples 1 to 5. Further, a sample using polyethylene glycol powder as a binder was Example 6, and a sample using carbomethylmethylcellulose powder was Example 7. On the other hand, the molybdenum containing aqueous solution which concerns on the comparative example 1 was prepared by processing like Example 1 except the heating temperature of water having been 35 degreeC.
Table 2 below shows the conditions of the adjustment process of the molybdenum-containing aqueous solution so far.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　比較例１のモリブデン含有水溶液は水の加熱温度が３５℃と、本発明で規定する温度の範囲外であるため、ＰＶＡ粉末の一部に未溶融の粉末が存在していた。
　次に、実施例１～７のモリブデン含有水溶液を使用して、スプレードライヤーによる造粒工程を実施した。スプレードライヤーによる造粒工程の条件を下記表３に示す。 Since the molybdenum-containing aqueous solution of Comparative Example 1 had a water heating temperature of 35 ° C., which was outside the temperature range defined in the present invention, an unmelted powder was present in a part of the PVA powder.
Next, using the molybdenum-containing aqueous solutions of Examples 1 to 7, a granulation step using a spray dryer was performed. Table 3 below shows the conditions of the granulation process using a spray dryer.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
実施例１Ａ～７Ａおよび比較例２～３の製造方法によって得られたモリブデン造粒粉の平均粒径、アスペクト比、見かけ密度、流動性および歩留りを調査した。
　なお、平均粒径は得られたモリブデン造粒粉の任意の１００粒を抜き出し、拡大写真を撮り、そこに写る最大径を求め、１００粒の平均値を平均粒径とした。アスペクト比は同様の拡大写真を使用し、短径Ｌ１および長径Ｌ２を求め、それぞれのＬ２／Ｌ１の平均値をアスペクト比とした。また、見かけ密度および流動性はＪＩＳ－Ｚ－２５０４に準拠した測定方法で測定した。また、歩留りは、投入したモリブデン粉末４０ｋｇ量とモリブデン造粒粉の合計量との比「（造粒粉の合計量／４０ｋｇ）×１００％」から算出した。
　それらの測定結果を下記表４に示す。 The average particle diameter, aspect ratio, apparent density, fluidity, and yield of the molybdenum granulated powder obtained by the production methods of Examples 1A to 7A and Comparative Examples 2 to 3 were investigated.
In addition, the average particle diameter extracted arbitrary 100 grains of the obtained molybdenum granulated powder, took the enlarged photograph, calculated | required the maximum diameter reflected there, and made the average value of 100 grains the average particle diameter. The aspect ratio used the same enlarged photograph, calculated | required the short diameter L1 and the long diameter L2, and made each average value of L2 / L1 the aspect ratio. The apparent density and fluidity were measured by a measuring method based on JIS-Z-2504. Further, the yield was calculated from the ratio of (the total amount of the granulated powder / 40 kg) × 100% of the amount of the molybdenum powder 40 kg and the total amount of the granulated molybdenum powder.
The measurement results are shown in Table 4 below.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　上記表４に示す結果から明らかなように、本実施例に係るモリブデン造粒粉の製造方法により製造されたモリブデン造粒粉は、目的とする平均粒径Ｂに対するずれが小さく、アスペクト比、見かけ密度および流動性が優れていた。また、歩留りも高く効率の良い製造方法であると言える。それに対し、Ａ／Ｂが本発明の範囲外である比較例２および比較例３では、いずれのパラメータも悪化した特性を示した。 As is clear from the results shown in Table 4 above, the molybdenum granulated powder produced by the method for producing molybdenum granulated powder according to this example has a small deviation from the target average particle diameter B, and has an aspect ratio and an apparent appearance. The density and fluidity were excellent. In addition, it can be said that this is an efficient manufacturing method with a high yield. On the other hand, Comparative Example 2 and Comparative Example 3 in which A / B is outside the range of the present invention showed characteristics in which both parameters deteriorated.
１…容器（モリブデン含有水溶液を調製するための容器）
２…水，純水
３…モリブデン粉末（ドープ剤添加モリブデン粉末）
４…バインダー
５…必要に応じて再度投入する水
６…モリブデン含有水溶液
７…モリブデン含有水溶液の投入口
８…回転板
９…モリブデン造粒粉
１０…スプレードライヤーの外壁
１１…モリブデン造粒粉の回収容器 1 ... Container (Container for preparing molybdenum-containing aqueous solution)
2 ... Water, pure water 3 ... Molybdenum powder (Molybdenum powder with added dopant)
4 ... Binder 5 ... Water to be recharged as required 6 ... Molybdenum-containing aqueous solution 7 ... Molybdenum-containing aqueous solution inlet 8 ... Rotary plate 9 ... Molybdenum granulated powder 10 ... Outer wall 11 of spray dryer ... Recovery of molybdenum granulated powder container

Claims (18)

  1. 容器に水を注入し、水を５０～８０℃に加熱する工程と、
    　加熱された水にバインダーを添加する工程と、
    　上記水を攪拌しながら、カリウム成分、アルミニウム成分およびケイ素成分の少なくとも１種を添加した平均粒径１～１０μｍのモリブデン粉末を投入することによりモリブデン含有水溶液を調製する工程と、
    　上記モリブデン含有水溶液を分散するスプレードライヤーの回転板の回転数をＡ（ｒｐｍ）とし、造粒粉の平均粒径をＢ（μｍ）としたときに、Ａ／Ｂが５０～７００の範囲であるスプレードライヤーに上記モリブデン含有水溶液を投入し、上記モリブデン含有水溶液を分散すると共に乾燥してモリブデン造粒粉を調製する工程と、
    　を有することを特徴とするモリブデン造粒粉の製造方法。     Injecting water into the container and heating the water to 50-80 ° C .;
    Adding a binder to the heated water;
    Preparing a molybdenum-containing aqueous solution by adding molybdenum powder having an average particle size of 1 to 10 μm to which at least one of a potassium component, an aluminum component and a silicon component is added while stirring the water;
    A / B is in the range of 50 to 700, where A (rpm) is the rotational speed of the rotating plate of the spray dryer for dispersing the molybdenum-containing aqueous solution and B (μm) is the average particle size of the granulated powder. Adding the molybdenum-containing aqueous solution to a spray dryer, dispersing the molybdenum-containing aqueous solution and drying to prepare molybdenum granulated powder; and
    A method for producing molybdenum granulated powder, comprising:
  2. 前記スプレードライヤーによる工程完了後の造粒粉に対して、平均粒径Ｂの２～３倍のメッシュ径を有する篩を通す篩分け工程をさらに実施することを特徴とする請求項１記載のモリブデン造粒粉の製造方法。 The molybdenum according to claim 1, further comprising a sieving step of passing through a sieve having a mesh size 2 to 3 times the average particle size B with respect to the granulated powder after completion of the step by the spray dryer. A method for producing granulated powder.
  3. 前記モリブデン造粒粉の平均粒径Ｂが２０～１５０μｍであることを特徴とする請求項１または請求項２に記載のモリブデン造粒粉の製造方法。 3. The method for producing a molybdenum granulated powder according to claim 1, wherein the average particle diameter B of the molybdenum granulated powder is 20 to 150 μm.
  4. 前記スプレードライヤーの回転板の回転数Ａが５０００～１６０００ｒｐｍであることを特徴とする請求項１乃至請求項３のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a molybdenum granulated powder according to any one of claims 1 to 3, wherein the rotational speed A of the rotating plate of the spray dryer is 5000 to 16000 rpm.
  5. 前記カリウム成分は、カリウム元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることを特徴とする請求項１乃至請求項４のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a granulated molybdenum powder according to any one of claims 1 to 4, wherein the potassium component is added in the range of 100 to 1000 ppm by mass in terms of potassium element.
  6. 前記アルミニウム成分は、アルミニウム元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることを特徴とする請求項１乃至請求項５のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a granulated molybdenum powder according to any one of claims 1 to 5, wherein the aluminum component is added in a range of 100 to 1000 ppm by mass in terms of an aluminum element simple substance.
  7. 前記ケイ素成分は、ケイ素元素単体換算で１００～１０００質量ｐｐｍの範囲で添加されることを特徴とする請求項１乃至請求項６のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a molybdenum granulated powder according to any one of claims 1 to 6, wherein the silicon component is added in a range of 100 to 1000 ppm by mass in terms of a single element of silicon.
  8. 前記バインダーがポリビニルアルコール粉末、ポリエチンレングリコール粉末およびカルボメキシメチルセルロース粉末の少なくとも１種であることを特徴とする請求項１乃至請求項７のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a granulated molybdenum powder according to any one of claims 1 to 7, wherein the binder is at least one of polyvinyl alcohol powder, polyethylene glycol powder and carbomethylmethylcellulose powder. .
  9. 投入する前記モリブデン粉末の合計量を１００体積部にしたときに、バインダーの体積を３～２０体積部とすることを特徴とする請求項１乃至請求項５のいずれか１項に記載のモリブデン造粒粉の製造方法。 The molybdenum structure according to any one of claims 1 to 5, wherein the volume of the binder is 3 to 20 parts by volume when the total amount of the molybdenum powder to be added is 100 parts by volume. A method for producing granules.
  10. 得られるモリブデン造粒粉の見かけ密度が１．３～３．０ｇ／ｃｃであることを特徴とする請求項１乃至請求項９のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a molybdenum granulated powder according to any one of claims 1 to 9, wherein an apparent density of the obtained molybdenum granulated powder is 1.3 to 3.0 g / cc.
  11. 前記モリブデン含有水溶液は、モリブデン粉末量を１００質量部としたときに、水量が０．２～１リットルであることを特徴とする請求項１乃至請求項１０のいずれか１項に記載のモリブデン造粒粉の製造方法。 The molybdenum structure according to any one of claims 1 to 10, wherein the molybdenum-containing aqueous solution has a water content of 0.2 to 1 liter when the amount of molybdenum powder is 100 parts by mass. A method for producing granules.
  12. 前記スプレードライヤーは、１５０～３００℃の熱風を供給しながらモリブデン造粒粉の乾燥を実施することを特徴とする請求項１乃至請求項１１のいずれか１項に記載のモリブデン造粒粉の製造方法。 12. The molybdenum granulated powder production according to claim 1, wherein the spray dryer dries the molybdenum granulated powder while supplying hot air of 150 to 300 ° C. Method.
  13. 前記スプレードライヤーは、大気圧以下の減圧雰囲気でモリブデン造粒粉の乾燥を実施することを特徴とする請求項１乃至請求項１２のいずれか１項に記載のモリブデン造粒粉の製造方法。 The method for producing a molybdenum granulated powder according to any one of claims 1 to 12, wherein the spray dryer performs drying of the molybdenum granulated powder in a reduced pressure atmosphere at atmospheric pressure or lower.
  14. 得られたモリブデン造粒粉の流動性が５０ｓｅｃ／５０ｇ以下であることを特徴とする請求項１乃至請求項１３のいずれか１項に記載のモリブデン造粒粉の製造方法。 The fluidity of the obtained molybdenum granulated powder is 50 sec / 50 g or less, The manufacturing method of the molybdenum granulated powder of any one of Claim 1 thru | or 13 characterized by the above-mentioned.
  15. 　カリウム成分、アルミニウム成分またはケイ素成分の少なくとも１種を含み、見かけ密度が１．３～３．０ｇ／ｃｃであることを特徴とするモリブデン造粒粉。 A molybdenum granulated powder comprising at least one of a potassium component, an aluminum component, or a silicon component and having an apparent density of 1.3 to 3.0 g / cc.
  16. 　前記モリブデン造粒粉の平均粒径が２０～１５０μｍであること特徴とする請求項１５に記載のモリブデン造粒粉。 The molybdenum granulated powder according to claim 15, wherein the average particle diameter of the molybdenum granulated powder is 20 to 150 µm.
  17. 　前記モリブデン粉末の合計量を１００体積部にしたときに、バインダーの体積が３～２０体積部であることを特徴とする請求項１５または請求項１６に記載のモリブデン造粒粉。 The molybdenum granulated powder according to claim 15 or 16, wherein the volume of the binder is 3 to 20 parts by volume when the total amount of the molybdenum powder is 100 parts by volume.
  18. 前記モリブデン粉末の流動性が５０ｓｅｃ／５０ｇ以下であることを特徴とする請求項１５乃至請求項１７のいずれか１項に記載のモリブデン造粒粉。 The molybdenum granulated powder according to any one of claims 15 to 17, wherein the fluidity of the molybdenum powder is 50 sec / 50 g or less.
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JPS59150073A (en) * 1983-02-10 1984-08-28 Toshiba Corp Production of molybdenum jig for high-temperature heat treatment
JPH0198764A (en) * 1987-10-08 1989-04-17 Teikoku Piston Ring Co Ltd Combination of cylinder and piston ring
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JP2004052020A (en) * 2002-07-17 2004-02-19 Matsushita Electric Ind Co Ltd Method for manufacturing transducer consisting of tungsten heavy alloy
JP2005120400A (en) * 2003-10-15 2005-05-12 Sumitomo Electric Ind Ltd Granular metal powder
JP2005291530A (en) * 2004-03-31 2005-10-20 Tdk Corp Spray drying device, powder drying method, and method of manufacturing ferrite particle
JP2008285759A (en) * 1995-11-27 2008-11-27 Hc Starck Gmbh Method for production of metal powder granulate

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* Cited by examiner, † Cited by third party
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JPS59150070A (en) * 1983-02-10 1984-08-28 Toshiba Corp Manufacture of molybdenum material
JPS59150073A (en) * 1983-02-10 1984-08-28 Toshiba Corp Production of molybdenum jig for high-temperature heat treatment
JPH0198764A (en) * 1987-10-08 1989-04-17 Teikoku Piston Ring Co Ltd Combination of cylinder and piston ring
JP2008285759A (en) * 1995-11-27 2008-11-27 Hc Starck Gmbh Method for production of metal powder granulate
JPH11199948A (en) * 1998-01-06 1999-07-27 Toshiba Corp Low-temperature-ductile material
JP2004052020A (en) * 2002-07-17 2004-02-19 Matsushita Electric Ind Co Ltd Method for manufacturing transducer consisting of tungsten heavy alloy
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