CN103130499B - A kind of preparation method of microwave dielectric ceramic materials - Google Patents
A kind of preparation method of microwave dielectric ceramic materials Download PDFInfo
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Abstract
The invention discloses a kind of preparation method of microwave dielectric ceramic materials, comprising: the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide is carried out mechanical uniform mixing in spherical tank, form powder granule; Powder granule is carried out first time high-energy ball milling, with by even for powder granule refinement; By the powder high-temperature calcination in closed container after first time high-energy ball milling, form presoma powder; Presoma powder is carried out second time high-energy ball milling, with by the evenly refinement further of presoma powder, forms ceramic powder.The preparation method of microwave dielectric ceramic materials of the present invention adopts the medium dielectric constant microwave medium of easy fired high compaction and the microwave dielectric ceramic materials of high quality factor, sintering temperature can be reduced to a great extent and shorten sintering time, and realize high compaction, thus reduce production cost and technical difficulty.
Description
Technical field
The present invention relates to ceramic material field, particularly relate to a kind of preparation method of microwave dielectric ceramic materials.
Background technology
Microwave-medium ceramics refer to be applied to 300MHz ~ 300GHz microwave frequency range in there is the ceramic material of fabulous dielectric property and be applied to the new function electron ceramic material completing one or more functions in microwave frequency band circuit as dielectric material, in microwave circuit, play the functions such as medium isolation, dielectric waveguide and dielectric resonance.
Due to perovskite structure (Ca, Sr) TiO
3-LaAlO
3(x represents molar percentage) base microwave medium ceramic material has high dielectric constant (30< ε
r<45), close to zero temperature coefficient of resonance frequency (τ
f~ 0) and quite high quality factor (Q × f>30000), extensive concern and the research of industry is caused.But, for the SrTiO that cost is more cheap
3-LaAlO
3base microwave medium ceramic material, the research of industry mainly rests in the correlation of its microstructure and dielectric property, and the research for its preparation method is little.
At present, the preparation method that domestic and international manufacturer mostly adopts mechanical mixture to be combined with solid-phase sintering, under high-temperature calcination condition, solid phase reaction occur after fully mixing in planetary or stirring ball mill by solid powder raw material and prepare required ceramic powder, and then compressing, solid-phase sintering becomes medium ceramic material.This traditional preparation method mainly contains following defect: in high-temperature sintering process, powder reactivity is poor, needs very high sintering temperature (more than at least 1580 degrees Celsius; 1580 ~ 1680 degrees Celsius), result in high energy consumption, even if adopt lqiuid phase sintering method to reduce sintering temperature, but reduce limitation (1430 ~ 1460 degrees Celsius), also can the dielectric property of destruction finished product in various degree; The ceramic powder particle diameter of Reactive Synthesis is comparatively large, and particle size distribution is wide, is difficult to realize sintering high compaction, and its uniformity also only has and ensures by extending incorporation time, is namely difficult to obtain the medium ceramic material possessing and stablize excellent microwave dielectric property.
Therefore, need the preparation method that a kind of microwave dielectric ceramic materials is provided, prepare in microwave dielectric ceramic materials process that sintering temperature is too high, sintering time is longer and be difficult to realize the problem of sintering densification to solve in prior art.
Summary of the invention
The technical problem that the present invention mainly solves is to provide a kind of preparation method of microwave dielectric ceramic materials, can prepare in microwave dielectric ceramic materials process reduce sintering temperature and shorten sintering time.
For solving the problems of the technologies described above, the invention provides a kind of preparation method of microwave dielectric ceramic materials, comprise: the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide is carried out mechanical uniform mixing, form powder granule, wherein, the molar percentage of described strontium carbonate and described titanium dioxide is 0.1mol% ~ 0.7mol%, and the molar percentage of described aluminium oxide and described lanthana is 0.15mol% ~ 0.45mol%; Powder granule is carried out first time high-energy ball milling, and with by even for powder granule refinement, wherein, ratio of grinding media to material is 8:1 ~ 10:1, and Ball-milling Time is 3 ~ 6 hours, and rotating speed is 400 ~ 800 revs/min; By the powder high-temperature calcination in closed container after first time high-energy ball milling, form presoma powder; Presoma powder is carried out second time high-energy ball milling, with by the further evenly refinement of presoma powder, form ceramic powder, wherein, ratio of grinding media to material is 10:1 ~ 12:1, Ball-milling Time 3 ~ 6 hours, rotating speed is 600 ~ 1000 revs/min, and add modifying dopant, property-modifying additive and sintering aid further, described modifying dopant is the oxide containing rare earth element, described rare earth element is one or more in yttrium, neodymium, cerium, praseodymium, samarium, europium, gadolinium, dysprosium, erbium and ytterbium, and described property-modifying additive is CaO, SrO, TiO
2, ZnO, Al
2o
3, Nb
2o
5and Ta
2o
5in one or more, described sintering aid is Bi
2o
3, B
2o
3, CuO, V
2o
5and one or more in BaO.
Wherein, also comprise after second time high-energy ball milling: mist projection granulating, in ceramic powder, add that concentration is 5%, mass percent is the polyvinyl alcohol water solution of 5% ~ 10%, ceramic powder is made the powder granule of the spherical mobility of tool.
Wherein, also comprise after mist projection granulating: compressing, the powder granule of spherical for tool mobility is made the pressed compact of required form.
Wherein, pressed compact carries out two-sided compressing by forcing press in filler mode manually or automatically, or it is shaping to carry out a shot by shot forming technique.
Wherein, also comprise after compressing: sintering, pressed compact is carried out continuous sintering, form ceramic blank, wherein, most high sintering temperature is 1300 ~ 1500 degrees Celsius, and temperature retention time is 3 ~ 6 hours.
Wherein, also comprise after sintering: machining and sample detection, ceramic blank is carried out surface treatment and obtains sample, and measure the dielectric property index of sample.
Wherein, the purity of strontium carbonate and aluminium oxide is all greater than 99.5%, and the purity of titanium dioxide and lanthana is not less than 99.9%.
Wherein, the step that the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide carries out mechanical uniform mixing is comprised: in spherical tank, add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol or mixed powder is carried out mechanical uniform mixing as organic solvent by deionized water, and after formation powder granule, removing organic solvent carries out drying process, wherein, mixed powder, abrasive media, organic solvent three part by weight are 1:3:3 and account for 60% ~ 80% of spherical tank volume, and incorporation time is 6 ~ 10 hours.
Wherein, the particle size distribution of the powder after first time high-energy ball milling is within the scope of 1 ~ 2 μm.
Wherein, in high-temperature calcinations step, closed container is high-temperature crucible, and calcining heat is 1100 ~ 1350 degrees Celsius, and temperature retention time is 3 ~ 5 hours.
Wherein, the granularity of the ceramic powder after second time high-energy ball milling is less than 1 μm.
Wherein, the formula of microwave dielectric ceramic materials is according to chemical formula (1-x) SrTiO
3-x [La
1-yre
yalO
3] make molar percentage x and y wherein meet 0.3mol%≤x≤0.9mol% respectively, 0.1mol%≤y≤0.5mol%, wherein, the mass percent of property-modifying additive is 1% ~ 4% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount, and the mass percent of sintering aid is 0.1% ~ 1% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount.
The invention has the beneficial effects as follows: the situation being different from prior art, the preparation method of microwave dielectric ceramic materials of the present invention is by carrying out twice high-energy ball milling making in process, sintering temperature can be reduced to a great extent and shorten sintering time, and realize high compaction, thus reduce production cost and technical difficulty.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings, wherein:
Fig. 1 is the schematic flow sheet of the preparation method of the microwave dielectric ceramic materials of the embodiment of the present invention;
Fig. 2 is in the preparation method of microwave dielectric ceramic materials according to an embodiment of the invention, prepares the particle size distribution figure of powder respectively through traditional mechanical mixture (a) and first time high-energy ball milling (b);
Fig. 3 is in the preparation method of microwave dielectric ceramic materials according to an embodiment of the invention, adopts traditional mechanical mixture+solid reaction process (a) and mechanical mixture of the present invention to obtain ESEM (SEM) image of STLA base microwave dielectric ceramics sample in conjunction with high-energy ball milling method (b) respectively.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only a part of embodiment of the present invention, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Embodiment one
A preparation method for microwave dielectric ceramic materials, its schematic flow sheet as shown in Figure 1, comprising:
Step S101, carries out mechanical uniform mixing by the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide, forms powder granule.
In the present embodiment, be placed in spherical tank after the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide is taken according to required molar percentage formula and carry out mechanical uniform mixing, and add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol or deionized water as organic solvent, and after formation powder granule, removing organic solvent carries out drying process, mixed powder, abrasive media, organic solvent three part by weight are 1:3:3 and account for 60% ~ 80% of spherical tank volume, and incorporation time is 6 ~ 10 hours.Wherein, the molar percentage of strontium carbonate and titanium dioxide is 0.1mol% ~ 0.7mol%, and the molar percentage of aluminium oxide and lanthana is 0.15mol% ~ 0.45mol%.The purity of strontium carbonate and aluminium oxide is all greater than 99.5%, and the purity of titanium dioxide and lanthana is not less than 99.9%.
Step S102, carries out first time high-energy ball milling by powder granule, with by even for powder granule refinement.
In the present embodiment, first time high-energy ball milling is carried out using zirconium dioxide abrading-ball as the abrasive media of high-energy ball milling, by the particle size distribution of the powder after first time high-energy ball milling within the scope of 1 ~ 2 μm, effectively improve reactivity and the contact area of powder granule, and then reach the object reducing calcination reaction synthesis temperature, wherein, ratio of grinding media to material is 8:1 ~ 10:1, Ball-milling Time is 3 ~ 6 hours, and rotating speed is 400 ~ 800 revs/min.
Step S103, by the powder high-temperature calcination in closed container after first time high-energy ball milling, forms presoma powder.
In the present embodiment, the powder after first time high-energy ball milling is placed in airtight high-temperature crucible, through the presoma powder of pyroreaction synthesis of high purity principal crystalline phase.The technological parameter of high-temperature burning process is: closed container is high-temperature crucible, and calcining heat is 1100 ~ 1350 degrees Celsius, and temperature retention time is 3 ~ 5 hours.
Step S104, carries out second time high-energy ball milling by presoma powder, with by the evenly refinement further of presoma powder, forms ceramic powder.
In the present embodiment, using zirconium dioxide abrading-ball as the abrasive media of high-energy ball milling, and add modifying dopant, property-modifying additive and sintering aid further and carry out second time high-energy ball milling.The granularity controlling the ceramic powder formed is less than 1 μm, and modifying dopant is the oxide containing rare earth element, and rare earth element is one or more in yttrium, neodymium, cerium, praseodymium, samarium, europium, gadolinium, dysprosium, erbium and ytterbium, and property-modifying additive is CaO, SrO, TiO
2, ZnO, Al
2o
3, Nb
2o
5and Ta
2o
5in one or more, sintering aid is Bi
2o
3, B
2o
3, CuO, V
2o
5and one or more in BaO, this microwave dielectric ceramic materials formula is according to chemical formula (1-x) SrTiO
3-x [La
1-yre
yalO
3] make molar percentage x and y wherein meet 0.3mol%≤x≤0.9mol% respectively, 0.1mol%≤y≤0.5mol%, wherein, the mass percent of property-modifying additive is 1% ~ 4% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount, and the mass percent of sintering aid is 0.1% ~ 1% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount.By adding modifying dopant, property-modifying additive and sintering aid, the object reducing sintering temperature and microwave-medium ceramics sintering densification can be reached.Wherein, ratio of grinding media to material is 10:1 ~ 12:1, Ball-milling Time 3 ~ 6 hours, rotating speed 600 ~ 1000 revs/min.
In addition, in the present embodiment, after ceramic powder is formed, can also be further comprising the steps as required:
Mist projection granulating, adds in ceramic powder that concentration is 5%, mass percent is the polyvinyl alcohol water solution of 5% ~ 10%, ceramic powder is made the powder granule of the spherical mobility of tool, this powder granule good fluidity.
Compressing, the powder granule of spherical for tool mobility is made the pressed compact of required form.
In the present embodiment, pressed compact carries out two-sided compressing by forcing press in filler mode manually or automatically, or it is shaping to carry out a shot by shot forming technique.
Sintering, carries out continuous sintering by pressed compact, forms ceramic blank, and wherein, most high sintering temperature is 1300 ~ 1500 degrees Celsius, and temperature retention time is 3 ~ 6 hours.
In the present embodiment, pressed compact is put into airtight high-temperature resistant aluminium oxide crucible and carry out continuous sintering, in the high temperature period, solid phase reaction occurs and generate fine and close ceramic blank.
Machining and sample detection, carry out surface treatment by ceramic blank and obtain sample, and measure the dielectric property index of sample.
In the present embodiment, surface treatment can adopt the machining such as grinding, polishing mode, obtains the test sample of required size, and measures its dielectric property index with network analyzer: DIELECTRIC CONSTANT ε
r, temperature coefficient of resonance frequency τ
fand quality factor q.
Embodiment two
A preparation method for microwave dielectric ceramic materials, comprising:
Step one, before batching by former for lanthana powder 800 degrees Celsius of lower pre-burnings 2 hours, and by former for titanium dioxide powder 1280 degrees Celsius of lower pre-burnings 3 hours, to carry out drying; According to chemical formula 0.68SrTiO
3-0.32LaAlO
3strontium carbonate, aluminium oxide, lanthana and titanium dioxide mixed powder are placed in spherical tank and carry out mechanical uniform mixing; Add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol or deionized water as organic solvent, and after formation powder granule, removing organic solvent carries out drying process, mixed powder, abrading-ball, solvent (weight) ratio is 1:3:3 and it accounts for 80% of spherical tank volume, and raw material incorporation time is 10 hours.
In the present embodiment, the stoichiometric proportion of strontium carbonate and titanium dioxide is 0.72mol%, and the stoichiometric proportion of aluminium oxide and lanthana is 0.28mol%.It should be noted that, the purity of strontium carbonate and alumina powder is all greater than 99.5%, and the purity of titanium dioxide and lanthana powder is not less than 99.9%.
Step 2, with zirconium dioxide abrading-ball for abrasive media, obtain the mixed material of even refinement by carrying out first time high-energy ball milling after the powder drying of step one.Wherein, High Energy Ball Milling Time is 6 hours, and ratio of grinding media to material is 10:1, and rotating speed is 500 revs/min.
Step 3, the mixed material of step 2 is placed in airtight high-temperature crucible, there is through high-temperature calcination Reactive Synthesis the presoma powder of high-purity principal crystalline phase; Calcining heat is 1150 degrees Celsius, and temperature retention time is 5 hours.
Step 4, with zirconium dioxide abrading-ball for abrasive media, powder after calcining is carried out the ceramic powder that second time high-energy ball milling obtains further evenly refinement.Wherein, High Energy Ball Milling Time is 4 hours, and ratio of grinding media to material is 10:1, and rotating speed is 1000 revs/min.
Step 5, obtain in powder, adding polyvinyl alcohol (PVA) aqueous solution (concentration is 5%) that percent mass ratio is 10% in step 4, utilize drying tower or comminutor to make the spherical and powder granule of good fluidity.
Step 6, with forcing press (manually or automatically filler), powder granule is made the pressed compact of required form, adopt two-sided compacting, its pressing pressure is 120MPa; Or, adopt shot forming technique also can obtain the pressed compact of required form.
Step 7, pressed compact is put into the high-temperature resistant aluminium oxide crucible of sealing, carry out continuous sintering.Wherein, most high sintering temperature is 1500 degrees Celsius, and temperature retention time is 6 hours.
Step 8, taking-up burn till porcelain body blank, obtain required test sample size after the surface treatment such as grinding, polishing.Then, utilize network analyzer to record its dielectric property index to be respectively: ε
r=56.4; τ
f=32.7ppm/ DEG C; Q × f=46800 (test frequency is 10GHz).
Embodiment three
A preparation method for microwave dielectric ceramic materials, comprising:
Step one, before batching by former for lanthana powder 800 degrees Celsius of lower pre-burnings 2 hours, and by former for titanium dioxide powder 1280 degrees Celsius of lower pre-burnings 3 hours, to carry out drying; According to chemical formula 0.52SrTiO
3-0.48LaAlO
3strontium carbonate, aluminium oxide, lanthana, titanium dioxide mixed powder are placed in spherical tank and carry out mechanical uniform mixing; Add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol or deionized water as organic solvent, mixed powder, abrading-ball, solvent (weight) ratio is 1:3:3 and it accounts for 60% of spherical tank volume, and raw material incorporation time is 8 hours.
In the present embodiment, the stoichiometric proportion of strontium carbonate and titanium dioxide is 0.62mol%, and the stoichiometric proportion of aluminium oxide and lanthana is 0.38mol%.It should be noted that, the purity of strontium carbonate and alumina powder is all greater than 99.5%, and the purity of titanium dioxide and lanthana powder is not less than 99.9%.
Step 2, with zirconium dioxide abrading-ball for abrasive media, dried for step one powder is carried out first time high-energy ball milling to obtain the mixed material of even refinement.Wherein, High Energy Ball Milling Time is 4 hours, and ratio of grinding media to material is 12:1, and rotating speed is 800 revs/min.
Step 3, the mixed material of step 2 is placed in airtight high-temperature crucible, there is through pyroreaction synthesis the presoma powder of high-purity principal crystalline phase.Wherein, calcining heat is 1280 degrees Celsius, and temperature retention time is 4 hours.
Step 4, with zirconium dioxide abrading-ball for abrasive media, powder after calcining is carried out the ceramic powder that second time high-energy ball milling obtains further evenly refinement.Wherein, High Energy Ball Milling Time is 4 hours, and ratio of grinding media to material is 10:1, and rotating speed is 800 revs/min.
Add polyvinyl alcohol (PVA) aqueous solution (concentration is 5%) that percent mass ratio is 8% in step 5, the powder that obtains in step 4, utilize drying tower or comminutor to make the spherical and powder granule of good fluidity.
Step 6, with forcing press (manually or automatically filler), powder granule is made the pressed compact of required form, adopt two-sided compacting, its pressing pressure is 120MPa; Or, adopt shot forming technique also can obtain the pressed compact of required form.
Step 7, pressed compact is put into the high-temperature resistant aluminium oxide crucible of sealing, carry out continuous sintering.Wherein, most high sintering temperature is 1450 degrees Celsius, and temperature retention time is 4 hours.
Step 8, taking-up burn till porcelain body blank, obtain required test sample size after the surface treatment such as grinding, polishing.Then, utilize network analyzer to record its dielectric property index to be respectively: ε
r=45.3; τ
f=-1.5ppm/ DEG C; Q × f=63400 (test frequency is 10GHz).
Embodiment four
A preparation method for microwave dielectric ceramic materials, comprising:
Step one, before batching by former for lanthana powder 800 degrees Celsius of lower pre-burnings 2 hours, and by former for titanium dioxide powder 1280 degrees Celsius of lower pre-burnings 3 hours, to carry out drying; According to chemical formula 0.36SrTiO
3-0.64LaAlO
3strontium carbonate, aluminium oxide, lanthana, titanium dioxide mixed powder are placed in spherical tank and carry out mechanical uniform mixing; Add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol or deionized water as organic solvent, mixed powder, abrading-ball, solvent (weight) ratio is 1:3:3 and it accounts for 70% of spherical tank volume, and raw material incorporation time is 8 hours.
In the present embodiment, the stoichiometric proportion of strontium carbonate and titanium dioxide is 0.52mol%, and the stoichiometric proportion of aluminium oxide and lanthana is 0.48mol%.It should be noted that, the purity of strontium carbonate and alumina powder is all greater than 99.5%, and the purity of titanium dioxide and lanthana powder is not less than 99.9%.
Step 2, with zirconium dioxide abrading-ball for abrasive media, dried for step one powder is carried out first time high-energy ball milling to obtain the mixed material of even refinement.Wherein, High Energy Ball Milling Time is 5 hours, and ratio of grinding media to material is 10:1, and rotating speed is 600 revs/min.
Step 3, the mixed material of step 2 is placed in airtight high-temperature crucible, there is through pyroreaction synthesis the presoma powder of high-purity principal crystalline phase.Wherein, calcining heat is 1250 degrees Celsius, and temperature retention time is 6 hours.
Step 4, with zirconium dioxide abrading-ball for abrasive media, powder after calcining is carried out the ceramic powder that second time high-energy ball milling obtains further evenly refinement.Wherein, High Energy Ball Milling Time is 3 hours, and ratio of grinding media to material is 8:1, and rotating speed is 1000 revs/min.
Add polyvinyl alcohol (PVA) aqueous solution (concentration is 5%) that percent mass ratio is 5% in step 5, the powder that obtains in step 4, utilize drying tower or comminutor to make the spherical and powder granule of good fluidity.
Step 6, with forcing press (manually or automatically filler), powder granule is made the pressed compact of required form, adopt two-sided compacting, its pressing pressure is 100MPa; Or, adopt shot forming technique also can obtain the pressed compact of required form.
Step 7, pressed compact is put into the high-temperature resistant aluminium oxide crucible of sealing, carry out continuous sintering.Wherein, most high sintering temperature is 1400 DEG C, and temperature retention time is 6 hours.
Step 8, taking-up burn till porcelain body blank, obtain required test sample size after the surface treatment such as grinding, polishing.Then, utilize network analyzer to record its dielectric property index to be respectively: ε
r=38.6; τ
f=-25.8ppm/ DEG C; Q × f=78000 (test frequency is 10GHz).
Embodiment five
Due to embodiment three medium dielectric constant microwave medium and quality factor better, and temperature drift is less, the technological parameter identical with preparation method in embodiment three is adopted to carry out trial-production and the detection of different component proportioning sample in the present embodiment, thus the above embodiment of the present invention is applied in specific environment is described in detail, the key property index of gained sample refers to table 1.
Table 1 different component (x) proportioning (1-x) SrTiO
3-xLaAlO
3the dielectric property index of sample
Embodiment six
With embodiment three (0.52SrTiO
3-0.48LaAlO
3) powder is basic proportioning, appropriate interpolation modifying dopant, property-modifying additive and sintering aid, modifying dopant is the oxide containing rare earth element, rare earth element is one or more in yttrium, neodymium, cerium, praseodymium, samarium, europium, gadolinium, dysprosium, erbium and ytterbium, and property-modifying additive is CaO, SrO, TiO
2, ZnO, Al
2o
3, Nb
2o
5and Ta
2o
5in one or more, sintering aid is Bi
2o
3, B
2o
3, CuO, V
2o
5and one or more in BaO, this microwave dielectric ceramic materials formula is according to chemical formula (1-x) SrTiO
3-x [La
1-yre
yalO
3] make molar percentage x and y wherein meet 0.3mol%≤x≤0.9mol% respectively, 0.1mol%≤y≤0.5mol%, wherein, the mass percent of property-modifying additive is 1% ~ 4% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount, the mass percent of sintering aid is 0.1% ~ 1% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount, and adopt same process parameter to carry out trial-manufacture of sample and detection, thus the above embodiment of the present invention is applied in specific environment is described in detail, its key property index refers to table 2-4.
The dielectric property index of the rare-earth element modified doping sample of table 2 different ratio
The dielectric property index of the corresponding sample of table 3 different ratio property-modifying additive
The dielectric property index of the corresponding sample of table 4 different ratio sintering aid
In conjunction with high-energy ball-milling process on the basis that the embodiment of the present invention is provided in traditional mechanical mixture and solid phase reaction method, the even refinement of ceramic powder is impelled by first time high-energy ball milling, not only effectively reduce powder calcined temperature, and ensure that the ceramic powder that Reactive Synthesis principal crystalline phase purity is high.Impel powder granule evenly refinement further by second time high-energy ball milling, reduce sintering temperature, and ensure that the high compaction of porcelain body.
Refer to Fig. 2, Figure 2 shows that in the preparation method of microwave dielectric ceramic materials according to an embodiment of the invention, prepare the particle size distribution figure of powder respectively through traditional mechanical mixture (a) and first time high-energy ball milling (b).
Obviously can draw the powder particles high concentration that adopts the preparation method of microwave dielectric ceramic materials of the present invention to obtain and particle size distribution narrows obviously from figure, generally be less than 1 μm, and there is very high quality factor q.
Refer to Fig. 3, Figure 3 shows that in the preparation method of microwave dielectric ceramic materials according to an embodiment of the invention, adopt traditional mechanical mixture+solid reaction process (a) and mechanical mixture of the present invention to obtain ESEM (SEM) image of STLA base microwave dielectric ceramics sample in conjunction with high-energy ball milling method (b) respectively.
Obviously can find out that from figure the microwave dielectric ceramic materials adopting the preparation method of microwave dielectric ceramic materials of the present invention to obtain does not have obvious crackle and local hole, porcelain body even particle distribution and high compaction.
By the way, the preparation method of microwave dielectric ceramic materials of the present invention is by carrying out twice high-energy ball milling making in process, sintering temperature can be reduced to a great extent and shorten sintering time, and realizing high compaction, thus reducing production cost and technical difficulty.
The foregoing is only embodiments of the invention; not thereby the scope of the claims of the present invention is limited; every utilize specification of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (7)
1. a preparation method for microwave dielectric ceramic materials, is characterized in that, comprising:
The mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide is carried out mechanical uniform mixing, form powder granule, wherein, described in described powder, the molar percentage of strontium carbonate and described titanium dioxide is 0.1 ~ 0.7, and the molar percentage of described aluminium oxide and described lanthana is 0.15 ~ 0.45;
Described powder granule is carried out first time high-energy ball milling, and with by even for described powder granule refinement, wherein, ratio of grinding media to material is 8:1 ~ 10:1, and Ball-milling Time is 3 ~ 6 hours, and rotating speed is 400 ~ 800 revs/min;
By the powder high-temperature calcination in closed container after described first time high-energy ball milling, form presoma powder;
Described presoma powder is carried out second time high-energy ball milling, with by the further evenly refinement of described presoma powder, form ceramic powder, wherein, ratio of grinding media to material is 10:1 ~ 12:1, Ball-milling Time 3 ~ 6 hours, rotating speed is 600 ~ 1000 revs/min, and add modifying dopant, property-modifying additive and sintering aid further, described modifying dopant is the oxide containing rare earth element, described rare earth element is one or more in yttrium, neodymium, cerium, praseodymium, samarium, europium, gadolinium, dysprosium, erbium and ytterbium, and described property-modifying additive is CaO, SrO, TiO
2, ZnO, Al
2o
3, Nb
2o
5and Ta
2o
5in one or more, described sintering aid is Bi
2o
3, B
2o
3, CuO, V
2o
5and one or more in BaO;
Also comprise after described second time high-energy ball milling:
Mist projection granulating, adds in described ceramic powder that concentration is 5%, mass percent is the polyvinyl alcohol water solution of 5% ~ 10%, described ceramic powder is made the powder granule of the spherical mobility of tool;
Also comprise after described mist projection granulating:
Compressing, the powder granule of spherical for described tool mobility is made the pressed compact of required form;
Described compressing after also comprise:
Sintering, carries out continuous sintering by described pressed compact, forms ceramic blank, and wherein, most high sintering temperature is 1300 ~ 1500 degrees Celsius, and temperature retention time is 3 ~ 6 hours;
The step that the mixed powder of strontium carbonate, aluminium oxide, lanthana and titanium dioxide carries out mechanical uniform mixing is comprised: in spherical tank, add zirconium dioxide abrading-ball as abrasive media, add absolute ethyl alcohol, as organic solvent, mixed powder is carried out mechanical uniform mixing, and after formation powder granule, removing organic solvent carries out drying process, wherein, mixed powder, abrasive media, organic solvent three part by weight are 1:3:3 and account for 60% ~ 80% of spherical tank volume, and incorporation time is 6 ~ 10 hours;
The formula of microwave dielectric ceramic materials is according to chemical formula (1-x) SrTiO
3-x [La
1-yre
yalO
3] make molar percentage x and y wherein meet 0.3≤x≤0.9 respectively, 0.1≤y≤0.5, wherein, the mass percent of described property-modifying additive is 1% ~ 4% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount, and the mass percent of described sintering aid is 0.1% ~ 1% of strontium carbonate, aluminium oxide, lanthana and titanium dioxide total amount.
2. the preparation method of microwave dielectric ceramic materials according to claim 1, is characterized in that, described pressed compact carries out two-sided compressing by forcing press in filler mode manually or automatically, or it is shaping to carry out a shot by shot forming technique.
3. the preparation method of microwave dielectric ceramic materials according to claim 1, it is characterized in that, also comprise after described sintering: machining and sample detection, described ceramic blank is carried out surface treatment and obtains sample, and measure the dielectric property index of described sample.
4. the preparation method of microwave dielectric ceramic materials according to claim 1, is characterized in that, the purity of described strontium carbonate and aluminium oxide is all greater than 99.5%, and the purity of described titanium dioxide and lanthana is not less than 99.9%.
5. the preparation method of microwave dielectric ceramic materials according to claim 1, is characterized in that, the particle size distribution of the powder after described first time high-energy ball milling is within the scope of 1 ~ 2 μm.
6. the preparation method of microwave dielectric ceramic materials according to claim 1, is characterized in that, in high-temperature calcinations step, closed container is high-temperature crucible, and calcining heat is 1100 ~ 1350 degrees Celsius, and temperature retention time is 3 ~ 5 hours.
7. the preparation method of microwave dielectric ceramic materials according to claim 1, is characterized in that, the granularity of the ceramic powder after described second time high-energy ball milling is less than 1 μm.
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| CN104446477B (en) * | 2014-12-08 | 2016-04-27 | 苏州艾福电子通讯股份有限公司 | Microwave dielectric ceramic powder and method, microwave-medium ceramics, microwave device |
| CN105198423B (en) * | 2015-08-18 | 2017-07-21 | 电子科技大学 | Sr La Al base microwave medium ceramic materials and preparation method thereof |
| CN105399422A (en) * | 2015-12-15 | 2016-03-16 | 广东国华新材料科技股份有限公司 | STLA microwave dielectric ceramic material and preparation method and application thereof |
| CN106316395B (en) * | 2016-08-08 | 2019-09-13 | 苏州博恩希普新材料科技有限公司 | The microwave-medium ceramics and preparation method of a kind of high dielectric constant, high-quality-factor |
| CN108393483A (en) * | 2017-02-07 | 2018-08-14 | 江苏天超细金属粉末有限公司 | A kind of metal powder injection molding feeding and preparation method thereof |
| CN107555992B (en) * | 2017-09-27 | 2020-02-07 | 广东国华新材料科技股份有限公司 | Microwave dielectric ceramic material and preparation method thereof |
| CN109020542A (en) * | 2018-08-28 | 2018-12-18 | 张家港保税区灿勤科技有限公司 | The preparation method of medium dielectric constant microwave medium ultra high quality factor microwave-medium ceramics |
| CN109231967B (en) * | 2018-10-15 | 2021-05-25 | 桂林理工大学 | Bi2O3-B2O3Binary system microwave dielectric ceramic material and preparation method thereof |
| CN111377706A (en) * | 2018-12-31 | 2020-07-07 | 深圳市大富科技股份有限公司 | Microwave dielectric ceramic material, dielectric ceramic block and microwave communication equipment |
| CN111377707A (en) * | 2018-12-31 | 2020-07-07 | 深圳市大富科技股份有限公司 | Microwave dielectric ceramic material and preparation method of dielectric ceramic block |
| CN111517758A (en) * | 2019-02-03 | 2020-08-11 | 苏州艾福电子通讯股份有限公司 | Microwave dielectric ceramic powder and preparation method and application thereof |
| CN111423227B (en) * | 2020-03-31 | 2022-04-01 | 厦门松元电子股份有限公司 | Microwave dielectric ceramic material with medium dielectric constant and high Qf and preparation method thereof |
| CN111675531B (en) * | 2020-07-01 | 2022-07-19 | 山西省玻璃陶瓷科学研究所（有限公司） | BMT-BZT composite novel microwave dielectric ceramic material and preparation method thereof |
| CN114031390B (en) * | 2021-12-14 | 2023-01-10 | 广东国华新材料科技股份有限公司 | Microwave dielectric material and preparation method thereof |
| CN115108825B (en) * | 2022-06-29 | 2023-09-15 | 电子科技大学 | (Sr,Ca)（Ti,Ga）O 3 -LaAlO 3 Composite microwave dielectric ceramic material and preparation method thereof |
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