Patent ID: 9478356
Filing Date: 2016-10-25
CPC Classification: C01G,C01P,C04B,H01G

Claim Text:
1. A method for producing a coated barium titanate particle comprising a coating layer comprising a carbonate of at least one type of metal selected from a group consisting of Mg, Ca, Ba, Mn and rare earth elements on a surface of a barium titanate particle, wherein the barium titanate particle without the coating has a mean particle size of 10 nm or higher and lower than 1000 nm, a Ba/Ti ratio of 0.80 or higher and 1.20 or lower, and a c/a ratio, which is a rate of a c-axis and an a-axis, of 1.001 or higher and 1.010 or lower comprising the steps of: (1) mixing an aqueous solution containing barium hydroxide and an aqueous solution containing titanium hydroxide at a Ba/Ti ratio of barium and titanium of 0.80 or higher and 1.20 or lower, and subjecting a resulting mixture to a hydrothermal reaction at a temperature of 200° C. or higher and 450° C. or lower, a pressure of 10 MPa or higher and 40 MPa or lower, and a reaction time of 0.1 minute or longer and 1 hour or shorter to obtain barium titanate particles; (2) homogenously dispersing the barium titanate particle obtained in (1) in an aqueous solution; and (3) adding a metal compound solution and alkali to a dispersion solution of barium titanate particles obtained in (2) to deposit a carbonate of metal on surfaces of the barium titanate particles.