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CN-121974690-A - Bismuth calcium niobate textured ceramic and preparation method thereof

CN121974690ACN 121974690 ACN121974690 ACN 121974690ACN-121974690-A

Abstract

The invention relates to the field of piezoelectric materials and discloses a bismuth calcium niobate textured ceramic and a preparation method thereof, wherein the bismuth calcium niobate textured ceramic is prepared by sintering a casting film prepared from ceramic slurry, the ceramic slurry comprises a base material, a solvent, a template agent and a film forming system, the base material comprises calcium carbonate, bismuth oxide and niobium pentoxide, the film forming system comprises triolein, di-N-octyl phthalate and polyvinyl butyral, the crack of the casting film prepared from the ceramic slurry is obviously reduced, the microscopic defects of the prepared ceramic are obviously reduced, the piezoelectric constant of the bismuth calcium niobate textured ceramic is obviously improved and can reach 35.8-36.8 pC/N, in addition, the upper limit of the knife height of one-time casting of the ceramic slurry is obviously improved, the stacking times of the casting film are obviously reduced, and the processing efficiency is obviously improved.

Inventors

  • FAN WENYING
  • YAO FANGZHOU
  • WU QIONG
  • XIE HANG
  • YU DONGFANG
  • CHEN BINJIE

Assignees

  • 乌镇实验室
  • 湖州心元科技有限公司

Dates

Publication Date
20260505
Application Date
20260228

Claims (10)

  1. 1. The bismuth calcium niobate textured ceramic is characterized in that the bismuth calcium niobate textured ceramic is prepared by sintering a casting film prepared from ceramic slurry, wherein the ceramic slurry comprises a base material, a solvent, a template agent and a film forming system, the base material comprises calcium carbonate, bismuth oxide and niobium pentoxide, and the film forming system comprises di-n-octyl phthalate and polyvinyl butyral.
  2. 2. The bismuth calcium niobate textured ceramic according to claim 1, wherein the mass ratio of the solvent to the base material is 0.3-0.6:1, the mass ratio of the template agent to the base material is 0.1-0.15:1, the mass ratio of the film forming system to the base material is 0.01-0.1:1, and the mass ratio of di-n-octyl phthalate to polyvinyl butyral is 0.4-0.5:0.1-0.2.
  3. 3. The bismuth calcium niobate textured ceramic according to claim 1 or 2, wherein the solvent is one or more of absolute ethanol, xylene and toluene, and the templating agent is a CaBi 2 Nb 2 O 9 template.
  4. 4. The bismuth calcium niobate textured ceramic according to claim 1, wherein the bismuth calcium niobate textured ceramic has a chemical formula of Ca 1-x (Li 0.5 Bi 0.5 ) x Bi 2-y Ce y Nb 2 O 9 , wherein x is 0 to 0.5 and y is 0 to 0.2.
  5. 5. The bismuth calcium niobate textured ceramic according to claim 1 or 4, wherein the bismuth calcium niobate textured ceramic base material is a solid phase sintered base material.
  6. 6. A method for preparing the bismuth calcium niobate textured ceramic according to any one of claims 1 to 5, comprising the steps of: (1) Ball milling and mixing the base material, the solvent, the template agent and the film forming system to prepare slurry; (2) And (3) carrying out curtain coating drying on the slurry to prepare a curtain coating film, cutting the curtain coating film into a blank body, pressurizing and superposing the blank body, discharging glue, and sintering to prepare the bismuth calcium niobate textured ceramic.
  7. 7. The method of claim 6, wherein the laminating conditions include a temperature of 60-120 ℃ and a pressure of 10-15 MPa.
  8. 8. The preparation method of claim 6, wherein the glue discharging condition comprises 600-650 ℃ and 200-250 MPa.
  9. 9. The method according to claim 6, wherein the sintering conditions comprise 1100-1200 ℃ for 3-8 hours.
  10. 10. The method according to claim 6, wherein the casting conditions include a knife height of 20 to 200 μm and a casting speed of 0.4 to 0.6 m/min.

Description

Bismuth calcium niobate textured ceramic and preparation method thereof Technical Field The invention relates to the field of piezoelectric materials, in particular to bismuth calcium niobate textured ceramic and a preparation method thereof. Background Advanced functional materials can realize specific functional response through external stimulus (light, heat, electric field, magnetic field and the like) and are widely applied to the fields of energy, environment, information technology, intelligent manufacturing and the like. Piezoelectric materials are important branches of advanced functional materials, and the core function is to realize mutual conversion of electromechanical energy, so that the piezoelectric materials are vigorously developed in the fields of electronic devices such as sensors, transducers, drivers and the like. With the promotion of deep environment application strategy such as deep sea, deep space and deep land in China, the demands for sensing and executing devices capable of stably working in extreme environments such as ultra-high temperature, high pressure, strong oxidation and strong corrosiveness are increasingly urgent. The high-temperature piezoelectric ceramic as a core material of the high-temperature piezoelectric sensor has higher requirements on the piezoelectric performance and stable operation in a high-temperature (more than or equal to 500 ℃) environment. Bismuth layered structure piezoelectric ceramics are considered to be one of the most promising material systems in high temperature piezoelectric applications due to their high curie temperature and excellent fatigue resistance. The crystal structure is formed by alternately arranging bismuth oxide layers and perovskite layers, and the special structure endows the material with high structural stability and degradation resistance. Bismuth calcium niobate is used as a bismuth lamellar structure compound with the highest Curie temperature, and the Curie point can reach more than 900 ℃. However, the bismuth calcium niobate piezoelectric material prepared by the traditional solid phase method has a crystal grain arrangement structure with strong anisotropism, which leads to low piezoelectric performance (d 33 <10 pC/N) and low resistivity at high temperature, so that practical application is limited. Aiming at the problems, the prior art provides a technical scheme of doping modification, but the doping modification can only finish microscopic repair, and the arrangement mode of crystal grains cannot be changed, so that the performance improvement is limited. In the technical scheme disclosed in publication No. CN118930263A, a bismuth calcium niobate textured ceramic with high consistent grain orientation is prepared by a template grain growth method (TGG), and the piezoelectric performance of the piezoelectric ceramic is remarkably improved. The preparation method of the technical scheme is to carry out casting film forming on the casting film, and prepare the piezoelectric ceramic by repeating the casting film forming for a plurality of times. According to the invention, after intensive research on the technical scheme, the reason that the method needs to adopt multiple casting is that the upper limit of the knife height of one-time casting is low, so that the thickness of the cast green film is low, the production efficiency is low, and therefore, the technical scheme needs to be further optimized. Disclosure of Invention The invention aims to improve the upper limit of the knife height of one-time casting, improve the wet film thickness, reduce the film forming defect, improve the piezoelectric performance of the bismuth calcium niobate textured ceramic and improve the processing efficiency of the bismuth calcium niobate textured ceramic. According to the invention, the ceramic slurry components for preparing the bismuth calcium niobate textured ceramic are optimized, and the cast film prepared from the ceramic slurry has obviously reduced cracks after drying, obviously reduced the defect number of the ceramic, obviously improved the piezoelectric performance of the ceramic, and the piezoelectric constant of the bismuth calcium niobate textured ceramic reaches 35.8-36.8 pC/N. The upper limit of the knife height of the ceramic slurry for one-time casting obviously improves the thickness of the green film, obviously reduces the lamination layer number and obviously improves the processing efficiency of the bismuth calcium niobate textured ceramic. The specific technical scheme of the invention is as follows: The bismuth calcium niobate textured ceramic is prepared by sintering a casting film prepared from ceramic slurry, wherein the ceramic slurry comprises a base material, a solvent, a template agent and a film forming system, the base material comprises calcium carbonate, bismuth oxide and niobium pentoxide, and the film forming system comprises di-n-octyl phthalate and polyvinyl butyral. Preferably, the mass rat