CN101891475A - Preparation method of potassium-sodium niobate-potassium-bismuth titanate nano ceramics - Google Patents

Abstract

The invention discloses a preparation method of potassium-sodium niobate-potassium-bismuth titanate nano ceramics. The potassium-sodium niobate-potassium-bismuth titanate contains niobium pentaoxide, sodium carbonate, potassium carbonate, titanium dioxide and dibismuth trioxide with the stoichiometric ratio of (1-x)[(Na0.5K0.5)NbO3]-x[(Bi0.5K0.5)TiO3], wherein x is more than 0.1 but less than 0.9; the potassium-sodium niobate-potassium-bismuth titanate nano ceramics is prepared by the procedures of material blending, high-energy ball milling of the mixed material, pre-sintering, cold isostatic pressing formation, high-temperature sintering, grinding and polishing and sputtering of gold electrode. According to the invention, since the grain size of the ceramics is effectively varied owing to the different ingredient proportions adopted, a series of electronic ceramics from micron level to nanometer level is prepared and further, the electronic ceramics with different piezoelectricity and dielectricity is prepared. The preparation method adopting the method of high-energy ball milling and appropriate chemical proportions achieves great simplicity, proper cost and excellent suitability for batch production.

Description

The preparation method of potassium-sodium niobate-potassium-bismuth titanate nano ceramics

Technical field

The present invention relates to a kind of preparation method of potassium-sodium niobate-potassium-bismuth titanate nano ceramics, belong to the function ceramics field.

Background technology

Document " Ruzhong Zuo, Xusheng Fang, and Chun Ye, Phase structures and electrical properties of new lead-free Na _0.5K _0.5NbO ₃-Bi _0.5Na _0.5TiO ₃Ceramics, APPLIED PHYSICS LETTERS 90,092904 (2007) " adopt traditional milling method to prepare the potassium-sodium niobate-sodium bismuth titanate pottery; common light ball (as alumina balls, zirconia ball and the agate ball) ball milling method that they adopt;, just to be difficult to make original powder to reach nano level at the preparation powder initial stage in conjunction with the pressureless sintering mode.In sintering subsequently, further the growing up of crystal grain makes the grain-size of pottery greatly between the 1-5 micron, is difficult to obtain fine and close nano ceramics.For the potassium-sodium niobate-bismuth potassium titanate of same system, adopt this production technique, also be difficult to obtain fine and close nano ceramics.

Summary of the invention

In order to overcome the excessive deficiency of potassium-sodium niobate-potassium-bismuth titanate ceramic crystalline grain of prior art for preparing, the present invention adopts the potassium-sodium niobate-potassium-bismuth titanate system solid solution, the method of a kind of high-energy ball milling refinement powder in conjunction with non-pressure sintering technology is provided, the potassium-sodium niobate-potassium-bismuth titanate system solid solution is carried out high-energy ball milling and pressureless sintering, prepared the potassium-sodium niobate-potassium-bismuth titanate nano ceramics of grain-size about 100 nanometers.

Potassium-sodium niobate-potassium-bismuth titanate nano ceramics, the chemical constitution general formula is: (1-x) [(Na _0.5K _0.5) NbO ₃]-x[(Bi _0.5K _0.5) TiO ₃], wherein: 0.1＜x＜0.9.

The potassium-sodium niobate-potassium-bismuth titanate nano ceramics preparation method is:

(1), be (1-x) [(Na by stoichiometric ratio with Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide _0.5K _0.5) NbO ₃]-x[(Bi _0.5K _0.5) TiO ₃] batching, wherein: 0.1＜x＜0.9; The prescription of design potassium-sodium niobate-potassium-bismuth titanate pottery is formed, by stoichiometric ratio weighing carbonate and oxide compound;

(2) material that step (1) is prepared is put into the high-energy ball milling jar, and raw materials quality is the 1-19% of mill ball quality; Individual hour of raw material ball milling 1-12 in high energy ball mill, rotating speed is 200-500 rev/min, does not add any ball-milling medium in the mechanical milling process;

(3) material that step (2) is mixed is under 600-1100 ℃ of temperature pre-burning 0.5-4 hour;

(4) take out step (3) incinerating raw material and grind,, the calcining raw materials that grinds can be put into the high energy ball mill ball milling 0.5-3 hour once more, also can not carry out secondary ball milling for further refinement powder;

(5) powder with step (4) gained carries out granulation, puts into die for molding, and forming pressure is 100-400MPa, also can directly adopt cold isostatic compaction without granulation process, and forming pressure is 300-900MPa, keep-ups pressure to be 1-10 minute;

(6) biscuit of ceramics that step (5) is obtained is put into sintering oven, in 850-1300 ℃ of temperature range sintering 0.5-6 hour, obtains potassium-sodium niobate-potassium-bismuth titanate nano ceramics.

The invention has the beneficial effects as follows: owing to adopted high-energy ball milling refinement powder, increased the surface energy of powder, improved sintering power, made material under lower temperature, just can reach the purpose of sintering densification.Simultaneously, low-temperature sintering has effectively suppressed grain growth, has reached the purpose of crystal grain thinning, thereby makes this method just can obtain nano ceramics down normal pressure-sintered.In addition, change the component of material, changed the kinetics of grain growing, thereby improved the microscopic appearance of material.The present invention has simplified production technique effectively and has reduced production cost, successful preparation the electronic ceramics of nanocrystalline grain size.Compare and pure potassium-sodium niobate and bismuth potassium titanate grain-size has been reduced to～100 nanometers by～4000 nanometers.

Description of drawings

Fig. 1 is 0.85[(Na of the present invention _0.5K _0.5) NbO ₃]-0.15[(Bi _0.5K _0.5) TiO ₃] in 2 hours XRD figure spectrums of 850 ℃ of pre-burnings;

Fig. 2 is 0.80[(Na of the present invention _0.5K _0.5) NbO ₃]-0.20[(Bi _0.5K _0.5) TiO ₃] at 4 hours microstructure photos of 1090 ℃ of sintering.

Embodiment

Embodiment 1:

With analytical pure level Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide powder is raw material, and 120 ℃ of oven dry are after 24 hours, according to chemical formula 0.85Na _0.5K _0.5NbO ₃-0.15Bi _0.5K _0.5TiO ₃Proportioning, the various raw material powders of weighing.The gained powder directly carries out the mechanical alloying ball milling without any special processing, and raw materials quality is 5% of a mill ball quality; Do not add any ball-milling medium, the ball milling time is 8 hours, and rotating speed is 450 rev/mins; Powder after having ground was calcined 2 hours down at 850 ℃, made each raw material powder fully react; Fig. 1 provides the XRD figure spectrum of powder, and calculating powder grain size by the Scherrer formula is 31 nanometers.With the metal die pressing machine compression moulding of putting into diameter 10mm after the granulation of incinerating niobate material powder, pressure is 350MPa, pressurize 2 minutes.Then base substrate was carried out sintering 4 hours under 1050 ℃, to obtain the higher piezoelectric ceramics sample of density.The sample that sintering is later, through operation such as sanding and polishing, under the temperature that is lower than 100 ℃ of sintering temperatures, thermal etching half hour.With the microtexture pattern of sem observation sample, use intercept method to calculate grain-size, obtaining its grain-size is 95 nanometers.

Embodiment 2:

With analytical pure level Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide powder is raw material, and 120 ℃ of oven dry are after 24 hours, according to chemical formula 0.80Na _0.5K _0.5NbO ₃-0.20Bi _0.5K _0.5TiO ₃Proportioning, the various raw material powders of weighing.The gained powder directly carries out the mechanical alloying ball milling without any special processing, and raw materials quality is 8% of a mill ball quality, does not add any ball-milling medium, and the ball milling time is 4 hours, and rotating speed is 450 rev/mins; Powder after having ground was calcined 2 hours down at 950 ℃, made each raw material powder fully react; In the vacuum bag of packing into after the precompressed of incinerating niobate material, exhaust vacuum, to put in the oil press, pressure is 650MPa, keep-ups pressure 8 minutes; Then base substrate was carried out sintering 4 hours under 1090 ℃, to obtain the higher piezoelectric ceramics sample of density.The sample that sintering is later, through operation such as sanding and polishing, under the temperature that is lower than 100 ℃ of sintering temperatures, thermal etching half hour.As the microtexture pattern of figure (2) with the sem observation sample, use intercept method to calculate grain-size, obtaining its grain-size is 89 nanometers.

Embodiment 3:

With analytical pure level Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide powder is raw material, and 120 ℃ of oven dry are after 24 hours, according to chemical formula 0.20Na _0.5K _0.5NbO ₃-0.80Bi _0.5K _0.5TiO ₃Proportioning, the various raw material powders of weighing.The gained powder directly carries out the mechanical alloying ball milling without any special processing, and raw materials quality is 15% of a mill ball quality, does not add any ball-milling medium, and the ball milling time is 4 hours, and rotating speed is 400 rev/mins; Powder after having ground was calcined 3 hours down at 650 ℃, made each raw material powder fully react; With the metal die pressing machine compression moulding that incinerating niobate material powder is put into diameter 10mm, pressure is 250MPa.Then base substrate was carried out sintering 2 hours under 1070 ℃, to obtain the higher piezoelectric ceramics sample of density.The sample that sintering is later, through operation such as sanding and polishing, under the temperature that is lower than 100 ℃ of sintering temperatures, thermal etching half hour.With the microtexture pattern of sem observation sample, use intercept method to calculate grain-size, obtaining its grain-size is 93 nanometers.

Embodiment 4:

With analytical pure level Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide is raw material, and 120 ℃ of oven dry are after 24 hours, according to chemical formula 0.50Na _0.5K _0.5NbO ₃-0.50Bi _0.5K _0.5TiO ₃Proportioning, the various raw material powders of weighing.The gained powder directly carries out the mechanical alloying ball milling without any special processing, and raw materials quality is 12% of a mill ball quality, does not add any ball-milling medium, and the ball milling time is 8 hours, and rotating speed is 350 rev/mins; Powder after having ground was calcined 1.5 hours down at 750 ℃, made each raw material powder fully react; In the vacuum bag of packing into after the precompressed of incinerating niobate material powder, exhaust vacuum, to put in the oil press, pressure is 850MPa, keep-ups pressure 4 minutes; Then base substrate was carried out sintering 4 hours under 1200 ℃, to obtain the higher piezoelectric ceramics sample of density.The sample that sintering is later, through operation such as sanding and polishing, under the temperature that is lower than 100 ℃ of sintering temperatures, thermal etching half hour.With the microtexture pattern of sem observation sample, use intercept method to calculate grain-size, obtaining its grain-size is 90 nanometers.

Claims (1)

1. the preparation method of a potassium-sodium niobate-potassium-bismuth titanate nano ceramics is characterized in that concrete steps are:

(1), be (1-x) [(Na by stoichiometric ratio with Niobium Pentxoxide, yellow soda ash, salt of wormwood, titanium dioxide, bismuthous oxide bismuth trioxide _0.5K _0.5) NbO ₃]-x[(Bi _0.5K _0.5) TiO ₃] batching, wherein: 0.1＜x＜0.9; The prescription of design potassium-sodium niobate-potassium-bismuth titanate pottery is formed, by stoichiometric ratio weighing carbonate and oxide compound;

(2) material that step (1) is prepared is put into the high-energy ball milling jar, and raw materials quality is the 1-19% of mill ball quality; Individual hour of raw material ball milling 1-12 in high energy ball mill, rotating speed is 200-500 rev/min, does not add any ball-milling medium in the mechanical milling process;

(3) material that step (2) is mixed is under 600-1100 ℃ of temperature pre-burning 0.5-4 hour;

(4) take out step (3) incinerating raw material and grind,, the calcining raw materials that grinds can be put into the high energy ball mill ball milling 0.5-3 hour once more, also can not carry out secondary ball milling for further refinement powder;

(5) powder with step (4) gained carries out granulation, puts into die for molding, and forming pressure is 100-400MPa, also can directly adopt cold isostatic compaction without granulation process, and forming pressure is 300-900MPa, keep-ups pressure to be 1-10 minute;

(6) biscuit of ceramics that step (5) is obtained is put into sintering oven, in 850-1300 ℃ of temperature range sintering 0.5-6 hour, obtains potassium-sodium niobate-potassium-bismuth titanate nano ceramics.

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