CN-121609563-B - Ultra-large piezoelectric ceramic hemisphere sintering method

Abstract

The invention discloses a sintering method of an oversized piezoelectric ceramic hemisphere, which belongs to the technical field of ceramics and comprises the following steps of 3D printing a firing supporting hemisphere component, firing the firing supporting hemisphere component and preparing a piezoelectric ceramic hollow hemisphere, wherein the 3D printing supporting hemisphere component is prepared by mixing TiO 2 、SiO 2 , mgO and alumina powder, dispersing the mixture in photosensitive resin, adding sucrose and ammonium citrate, regulating and controlling the solid content of slurry to 68-72wt%, ball milling for 23-25h after mixing, stirring the slurry for 0.8-1.2h at the speed of 900-1100 r/min, and then stirring the slurry for 8-12 min h at the speed of 180-220 r/min in vacuum to obtain a mixed slurry, and carrying out ultraviolet irradiation curing on the mixed slurry after 3D printing to obtain a cured component.

Inventors

• GAO XIAOYI
• YAN PEIKUN
• CAO SHOUGANG
• ZONG YUTING
• HE YEQING

Assignees

• 山东工业陶瓷研究设计院有限公司

Dates

Publication Date

20260512

Application Date

20260130

Claims (4)

1. 1. A sintering method of an oversized piezoelectric ceramic hemisphere is characterized by comprising the following steps of 3D printing a firing supporting hemisphere body component, firing the firing supporting hemisphere body, and preparing a piezoelectric ceramic hollow hemisphere; The method for the 3D printing firing hemisphere component comprises the steps of mixing TiO 2 、SiO 2 , mgO and alumina powder, dispersing in photosensitive resin, adding sucrose and ammonium citrate, regulating the solid content of slurry to 68-72wt%, ball milling for 23-25h after mixing, stirring the slurry for 0.8-1.2h at 900-1100 r/min, and stirring the slurry for 8-12 min in vacuum at 180-220r/min to obtain mixed slurry; The mass ratio of the alumina powder to the TiO 2 、SiO 2 to the MgO to the sucrose to the ammonium citrate is 100:9-11:4-5:2-2.5:2.5-3:1-1.5; The sintering method of the burning-bearing hemispherical body comprises the steps of degreasing a solidified component at 940-960 ℃, cooling to room temperature after heat preservation for 4.5-5.5h, sintering the degreased component for 1.4-1.6h under the air atmosphere and 1050-1150 ℃, heating to 1390-1400 ℃, switching to argon atmosphere, preserving heat for 2.4-2.6 h, and polishing the obtained sintered component after cooling to obtain the burning-bearing hemispherical body component; the burning-bearing hemispherical member consists of an inner hemispherical shell, an outer hemispherical shell and a base, wherein the inner hemispherical shell, the outer hemispherical shell and the base are uniformly provided with through hole structures, and the porosity is 65-75%; The preparation method of the piezoelectric ceramic hollow hemisphere comprises the steps of ball milling piezoelectric ceramic powder until the particle size is less than or equal to 1 um, drying, performing cold isostatic pressing and forming to obtain a piezoelectric ceramic hemisphere blank, assembling a ceramic hemisphere and a firing hemisphere component, placing the piezoelectric ceramic hemisphere blank between an inner hemisphere shell and an outer hemisphere shell, placing the piezoelectric ceramic hemisphere blank on a base, placing the whole body in an alumina crucible, placing the alumina crucible into a kiln for sintering, heating to 1280-1300 ℃, preserving heat for 2.4-2.6h, then cooling to room temperature, and taking out a sample to obtain the piezoelectric ceramic hollow hemisphere; the thickness of the piezoelectric ceramic hollow hemisphere is 8-12mm; The inner diameter of the piezoelectric ceramic hollow hemisphere is 250-350mm.
2. 2. The method for sintering an oversized piezoelectric ceramic hemisphere according to claim 1, wherein the purity of the alumina powder is more than or equal to 99.9%, and the particle size is less than or equal to 1 μm; the photosensitive resin contains 1-3wt% of photoinitiator; The ultraviolet irradiation time is 15-20s.
3. 3. The method for sintering an oversized piezoelectric ceramic hemisphere according to claim 1, wherein in the step of sintering the firing-supporting hemisphere, The temperature rising speed in the degreasing process is 0.08-0.12 ℃ per minute, the temperature reducing speed is 2.8-3.2 ℃ per minute, and the degreasing process is cooled to room temperature; The temperature rising speed is 0.8-1.2 ℃ per minute, the temperature reducing speed is 1.8-2.2 ℃ per minute in the sintering process, and the temperature is reduced to the room temperature; the degreasing atmosphere is formed by mixing argon and oxygen, and the oxygen content is 1.5-2vol%.
4. 4. The method for sintering an oversized piezoelectric ceramic hemisphere according to claim 1, wherein in the step of preparing the hollow piezoelectric ceramic hemisphere, The pressure of the cold isostatic pressing is 180-220 Mpa, and the pressure maintaining time is 9-11min; the temperature rising speed is 1-2 ℃ per minute and the temperature reducing speed is 1.8-2.2 ℃ per minute in the sintering process.

Description

Ultra-large piezoelectric ceramic hemisphere sintering method Technical Field The invention belongs to the technical field of ceramics, and particularly relates to a method for sintering an oversized piezoelectric ceramic hemisphere. Background The piezoelectric ceramic hemisphere occupies a core position in high-end fields such as underwater sound detection and communication, medical ultrasonic focusing treatment, large-scale structural health monitoring, high-power ultrasonic transducers and the like by virtue of excellent axisymmetric acoustic directivity, high electromechanical coupling coefficient and stable energy conversion efficiency. The electro-acoustic conversion performance of such components is highly dependent on the geometric accuracy and material consistency of the sintered ceramic hemispheres. For a small piezoelectric ceramic hemisphere with the diameter of several millimeters to several tens of millimeters, because the dead weight and the thermal mass of a blank are low, the creep deformation and collapse risks induced by gravity in the sintering process are extremely low, and the temperature field and the atmosphere field in the blank are uniformly distributed, the problems of warpage, cracking and uneven densification caused by thermal stress can be effectively restrained. Meanwhile, the small-size green body can be prepared by conventional processes such as block turning/grinding, cold isostatic pressing, finish machining, die forming, follow-up shaping and the like, the processing removal amount is small, the material waste is less, the processing window is wider, and the geometric precision and performance requirements can be stably met. However, with the upgrade of high-end equipment to high-power, long-distance and high-precision directions, the requirements on the oversized piezoelectric ceramic hemispheres with the inner diameters of more than or equal to 250mm are increasingly urgent, and the preparation of the oversized piezoelectric ceramic hemispheres is difficult to break through in the prior art. These defects will directly deteriorate the electrode uniformity, polarization uniformity of the device, limiting the application of large-sized hemispheres in high-power ultrasound scenarios. Therefore, developing a novel sintering technology capable of overcoming the multiple bottlenecks and realizing high-precision molding and high-performance consistency of the ultra-large piezoelectric ceramic hemispheres becomes a key difficult problem to be broken through in the field. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a method for sintering an oversized piezoelectric ceramic hemisphere, which solves the problems that the oversized piezoelectric ceramic is easy to generate irreversible creep and geometric collapse, improves the sintering geometric precision, reduces the density difference and improves the piezoelectric performance and the dielectric performance. In order to solve the technical problems, the technical scheme adopted by the invention is as follows: The sintering method of the oversized piezoelectric ceramic hemisphere comprises the following steps of 3D printing a firing supporting hemisphere component, sintering the firing supporting hemisphere, and preparing a piezoelectric ceramic hollow hemisphere; The method for the 3D printing firing hemisphere component comprises the steps of mixing TiO 2、SiO2, mgO and alumina powder, dispersing in photosensitive resin, adding sucrose and ammonium citrate, regulating the solid content of slurry to 68-72wt%, ball milling for 23-25h after mixing, stirring the slurry for 0.8-1.2h at 900-1100 r/min, and stirring the slurry for 8-12 min at 180-220r/min in vacuum to obtain mixed slurry; The purity of the alumina powder is more than or equal to 99.9 percent, and the particle size is less than or equal to 1 mu m; The mass ratio of the alumina powder to the TiO 2、SiO2 to the MgO to the sucrose to the ammonium citrate is 100:9-11:4-5:2-2.5:2.5-3:1-1.5; the photosensitive resin contains 1-3wt% of photoinitiator; the ball-milling material ratio of the ball mill is 4-5:1, and the ball-milling temperature is controlled at 10-15 ℃; The ultraviolet irradiation time is 15-20s. The sintering method of the burning-bearing hemispherical body comprises the steps of degreasing a solidified component at 940-960 ℃, cooling to room temperature after heat preservation for 4.5-5.5h, sintering the degreased component for 1.4-1.6h under the air atmosphere and 1050-1150 ℃, heating to 1390-1400 ℃, switching to argon atmosphere, preserving heat for 2.4-2.6 h, and polishing the obtained sintered component after cooling to obtain the burning-bearing hemispherical body component; The temperature rising speed in the degreasing process is 0.08-0.12 ℃ per minute, the temperature reducing speed is 2.8-3.2 ℃ per minute, and the degreasing process is cooled to room temperature; The temperature rising speed is 0.8-1.