Bismuth sodium potassium titanate-barium titanate-based composite ceramic material with high depolarization temperature and preparation method thereof

A preparation method of a bismuth sodium potassium titanate-barium titanate (BNKT-BT)-based composite ceramic material comprising a chemical general formula of:

• 0.85(Bi0.5Na0.5)TiO3-0.11(Bi0.5K0.5)TiO3-0.04BaTiO3-xZnO,
• wherein 0.1≤x≤0.3 with high depolarization temperatures, the preparation method comprising:
• S1, mixing a bismuth source, a sodium source, a potassium source, a titanium source and a barium source according to a stoichiometric ratio, ball milling with an organic solvent as a medium, drying and dry-pressing for molding to obtain a raw material block;
• S2, pre-sintering the raw material block in an oxygen atmosphere to obtain a BNKT-BT pre-sintered block;
• S3, mixing the BNKT-BT pre-sintered block with ZnO nanoparticles according to the stoichiometric ratio, performing secondary ball milling, drying, adding adhesive, standing, and pressing to obtain a sample;
• S4, grinding the pressed sample and sieving to obtain powder, and then re-pressing the obtained powder to obtain a ceramic blank;
• S5, sequentially heating, sintering, grinding and polishing the ceramic blank to obtain ZnO composite BNKT-BT-based ceramics;
• and
• S6, coating silver paste on a surface of the ZnO composite BNKT-BT-based ceramics, and performing silver-firing to obtain BNKT-BT-based composite ceramic material with high depolarization temperatures.