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CN-121974676-A - Heat treatment method of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic with high polarization intensity

CN121974676ACN 121974676 ACN121974676 ACN 121974676ACN-121974676-A

Abstract

The invention discloses a heat treatment method of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic, which comprises the steps of arranging electrodes on the surface of a bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic sintered body, then placing the ceramic sintered body in a rapid annealing furnace, carrying out first rapid annealing by raising the temperature of the ceramic sintered body from room temperature to 550-650 ℃ at a temperature of 45-75 s ℃ at a temperature of 5-80 ℃ and then lowering the temperature of the ceramic sintered body to room temperature at a temperature of 250-350 ℃ so as to obtain the bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic.

Inventors

  • ZHANG YAN
  • LI JINGZHI
  • ZHOU XUEFAN
  • ZHANG DOU

Assignees

  • 中南大学

Dates

Publication Date
20260505
Application Date
20260408

Claims (10)

  1. 1. A heat treatment method of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic is characterized by comprising the steps of arranging electrodes on the surface of a bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic sintered body, then placing the sintered body in a rapid annealing furnace, performing first rapid annealing by raising the temperature of the chamber to 550-650 ℃ at a temperature raising rate of 5-80 ℃ per second and preserving heat to 45-75 s, and then cooling to room temperature at a cooling rate of 250-350 ℃ per second to obtain the bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic.
  2. 2. The method for heat treatment of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic according to claim 1, wherein the bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic sintered body is obtained by placing a bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic compact in a small crucible fully filled with presintering powder, covering a cover of the small crucible, pouring the sealed small crucible outside the large crucible, and sintering.
  3. 3. The heat treatment method of the high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic is characterized in that the sintering process comprises the steps of heating to 500-600 ℃ at a heating rate of 1-3 ℃ per minute for 2-4 hours, conducting glue discharging, and then heating to 1000-1100 ℃ at a heating rate of 5-10 ℃ per minute for 2-4 hours, and conducting sintering.
  4. 4. The method for heat treatment of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic with high polarization intensity according to claim 1, wherein the electrode is a gold electrode.
  5. 5. The method for heat treatment of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic with high polarization intensity according to claim 4, wherein the gold electrode is obtained by spraying gold on the surface of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic sintered body.
  6. 6. The method for heat treatment of high polarization intensity bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic according to claim 1, wherein the first rapid annealing is performed by raising the temperature of the room from 150 to 250 ℃ at a temperature raising rate of 5 to 15 ℃ per second, and then raising the temperature from 150 to 250 ℃ to 550 to 650 ℃ at a temperature raising rate of 40 to 80 ℃ per second, and maintaining the temperature at 45 to 75 s.
  7. 7. The heat treatment method of the high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic according to claim 1, further comprising the steps of placing the product cooled to room temperature in a sintering furnace, heating to 550-650 ℃ at a heating rate of 5-10 ℃ per minute, preserving heat for 10-120min for annealing, cooling to room temperature, placing in a rapid annealing furnace, heating to 550-650 ℃ at a heating rate of 5-80 ℃ per second, preserving heat for 45-75 s, performing second rapid annealing, and cooling to room temperature at a cooling rate of 250-350 ℃ per second to obtain the bismuth ferrite-lead titanate-barium titanate-based ferroelectric ceramic.
  8. 8. The method for heat treatment of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic according to any one of claims 1 to 7, wherein the bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic has a chemical formula of (0.81-x) BiFeO 3 -0.19Ba(Zr 0.25 Ti 0.75 )O 3 -xPbTiO 3 , wherein x=0.19-0.33.
  9. 9. The method for heat treatment of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic according to claim 8, wherein the bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic has a chemical formula of (0.81-x) BiFeO 3 -0.19Ba(Zr 0.25 Ti 0.75 )O 3 -xPbTiO 3 , wherein x=0.25.
  10. 10. The method for heat treatment of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic according to claim 8, wherein the bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic has a chemical formula of (0.81-x) BiFeO 3 -0.19Ba(Zr 0.25 Ti 0.75 )O 3 -xPbTiO 3 , wherein x=0.29.

Description

Heat treatment method of bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic with high polarization intensity Technical Field The invention belongs to the field of high-temperature piezoelectric ceramics, and particularly relates to a heat treatment method of bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramics with high polarization intensity. Background Along with the development of industrial automation and aerospace technology, the high-temperature piezoelectric ceramic is widely applied to high-temperature sensors, actuators and ultrasonic equipment, and development and optimization of the piezoelectric ceramic with high curie temperature, high performance and excellent temperature stability become important research problems. Bismuth ferrite (BiFeO 3, BFO) has high Curie temperature (825 ℃) and high polarization intensity, but due to poor piezoelectric activity, the bismuth ferrite (BiFeO 3, BFO) is often dissolved with other perovskite ferroelectric ceramics with high piezoelectric activity, so that a multi-element bismuth ferrite-based ceramic system with high Curie temperature and high piezoelectric property is obtained, wherein the bismuth ferrite-lead titanate-barium zirconate titanate (BiFeO 3-PbTiO3-Ba(Zr,Ti)O3, BF-PT-BZT) based ferroelectric ceramics are paid attention to due to the high Curie temperature, high polarization intensity and good piezoelectric property. However, in the preparation process, the lead element and the bismuth element are easy to volatilize, and defects such as Fe 2+/Fe4+ ions, oxygen vacancies and the like are easy to form, so that larger leakage current, dielectric loss and hysteresis loop are not easy to open, thereby limiting the performance of the material. According to the prior art means, the optimization treatment of BF-PT-BZT only has relevant reports of MPB phase boundary component regulation at present, namely, by changing the content of BF, PT, BZT components, a ceramic system is in a multiphase coexisting state at normal temperature, the energy barrier of domain inversion is reduced, so that the piezoelectric activity of the ceramic is improved, the saturated polarization intensity of the ceramic prepared by the method can reach 22-41 mu C/cm 2, although bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic can be prepared, the volatilization problem of lead element and bismuth element cannot be avoided due to the fluctuation of a thermal field in the sintering process, the optimal component interval obtained by MPB phase boundary component regulation is narrow and is sensitive to the components, the process requirement is severe, the phenomenon of electric hysteresis loop beam waist caused by defect pinning cannot be improved, and the process repeatability is poor. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a heat treatment method of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic, which can lead defects in the ceramic to be rearranged and lead domain transfer switches to be increased, so that the ferroelectric and piezoelectric properties of the polarized BF-PT-BZT ceramic are greatly improved, and meanwhile, the high Curie temperature is achieved. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention relates to a heat treatment method of high-polarization-strength bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic, which comprises the steps of arranging electrodes on the surface of a bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic sintered body, then placing the electrodes in a rapid annealing furnace, performing first rapid annealing by raising the temperature of a chamber to 550-650 ℃ at a temperature raising rate of 5-80 ℃ per second and preserving heat to 45-75 s, and then cooling to room temperature at a cooling rate of 250-350 ℃ per second to obtain bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic. Experiments show that the rapid annealing can freeze an unbalanced defect configuration and a metastable phase structure, and in the invention, the typical sharp double current peaks of the ferroelectric shown by the obtained bismuth ferrite-lead titanate-barium zirconate titanate-based ferroelectric ceramic can be greatly improved by performing the rapid annealing once. Of course, to obtain excellent ferroelectric and piezoelectric properties, it is necessary to control the temperature rise and fall rates of the first rapid annealing within the scope of the present invention, which first employs rapid temperature rise to suppress oxygen vacancies and long-range diffusion thereof formed at high temperature to a certain extent and freeze disordered defect distribution, thereby weakening pi