Barium titanate foam ceramics loaded with micro/nano silver and preparation method thereof

A preparation method of barium titanate foam ceramics loaded with micro/nano silver, wherein comprising the following steps:

• (1) by weight, 100 parts of nano barium titanate and 30 to 120 parts of an aqueous solution of organic binder with a concentration of 1 to 15 wt % are sufficiently ground to obtain a slurry A;
• 10 to 80 parts of an aqueous solution of organic rheological agent with a concentration of 0.5 to 3 wt % are added into the slurry A to form a first mixture, and the first mixture is sufficiently ground to obtain a slurry B;
• 20 to 80 parts of an aqueous solution of organic dispersant with a concentration of 0.5 to 3 wt % are added into the slurry B to form a second mixture, and the second mixture is sufficiently ground to obtain a slurry C;
• (2) a polymer sponge having a specification of 15 to 35 PPI is soaked in an aqueous solution of sodium hydroxide with a concentration of 5 to 20 wt %, after heated up to 50 to 75° C. and kept at that temperature for 2 to 6 h, the polymer sponge is taken out and washed with deionized water, following by drying to obtain a polymer sponge D;
• at room temperature, the polymer sponge D is soaked in an aqueous surfactant solution with a concentration of 0.5 to 3 wt % for 2 to 6 h, then took out and removed the excess surfactant, after dried at 40 to 80° C., a pretreated polymer sponge E is obtained;
• (3) the pretreated polymer sponge E is soaked in the slurry C prepared in step (1), and maintained for 1 to 10 min at room temperature, an excess slurry in the sponge is removed by extrusion, and the sponge is dried at 40 to 80° C.;
• repeating processes of removing the excess slurry and drying for 1 to 7 times, a green body of foam ceramics based on barium titanate is obtained;
• (4) the green body of barium titanate foam ceramics prepared in step (3) is heated from room temperature to 100-300° C. at a rate of 0.5-5° C./min, and then raised to 500-700° C. at a rate of 0.5-5° C./min and maintained at that temperature for 0.5-2 h, after that, continuously heated to 1000-1500° C. at a rate of 2-10° C./min and kept at that temperature for 1-5 h, after the furnace is cooled to room temperature, barium titanate foam ceramics are obtained;
• (5) using buffering agent or buffer, water and dopamine hydrochloride to prepare dopamine aqueous solution with a concentration of 0.5-10 g/L;
• of which pH value is adjusted to 8.3-8.8 with alkali to obtain solution F;
• barium titanate foam ceramics prepared in step (4) are soaked in solution F and kept at room temperature for 1 to 24 h, followed by washing with deionized water and drying successively, to obtain dopamine-modified barium titanate foam ceramics;
• (6) by volume, 4 to 20 parts of stabilizer aqueous solution with a concentration of 0.1-1 wt % are added into 100 parts of a fresh ammoniacal silver solution with a concentration of 0.03-0.3 mol/L to form a third mixture, the third mixture is uniformly mixed to obtain solution G;
• the dopamine-modified barium titanate foam ceramics prepared in step (5) are soaked in solution G and kept at room temperature for 0.5-24 h to obtain barium titanate foam ceramics loaded with nano silver, into which 50-300 parts of reducing agent aqueous solution having a concentration of 1-30 g/L are added and kept at room temperature for 0.1-5 h, followed by washing with deionized water and drying successively, to obtain barium titanate foam ceramics loaded with micro/nano silver.