METHOD FOR OBTAINING POROUS PIEZOCERAMICS WITH ANISOTROPY OF DIELECTRIC PERMITTIVITY AND NUMBER OF OTHER PARAMETERS Russian patent published in 2018 - IPC H01L41/16 H01L41/187 C04B35/491 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to the production of porous piezoelectric ceramics for ultrasonic transducers operating in the frequency range of 0.1…2,000 kHz. This method’s essence lies in the fact that the powder of the original synthesized piezoceramic material is mixed with a two-component blowing agent, while the powder of the same original piezoceramic material previously calcined and ground is used as the first part of it, and as the second part of the blowing agent is a burnable blowing agent in the form of wood flour with the size of the main part of the particles 10÷180 microns. Said wood flour is a powder of easily deformable fibers. Further, a 5 % aqueous solution of polyvinyl alcohol is introduced into the mixture of powders, the mixture is thoroughly mixed, granulated, subjected to uniaxial semi-dry pressing under the pressure of 30÷35 MPa, pressed blanks are baked in chamber or tunnel kilns at temperatures of 1,150…1,250 °C.

EFFECT: obtaining piezo ceramics with porosity of 20÷40 %, with anisotropy of the dielectric constant and a number of other parameters, providing the possibility of increasing the longitudinal, volumetric and acoustic piezosensitivity g₃₃, g_v and γ_H respectively, as well as the reception factor d_vg_v while maintaining high piezo properties (d₃₃, k_t).

1 cl, 2 dwg, 3 tbl