Ceramic material powder, method of production thereof, dielectric ceramic composition, electronic device, and multilayer ceramic capacitor

Abstract

A ceramic material powder comprised of main ingredient particles formed by barium titanate having on their surfaces a covering layer comprised of a secondary ingredient additive, wherein when an average radius of the main ingredient particles is “r” and an average radius of the covering layer is “Δr”, the Δr is controlled to a range of 0.015 r to 0.055 r, thereby enabling acquisition of a multilayer ceramic capacitor or other electronic device satisfying both the X7R characteristic prescribed in the EIAJ standard and B characteristic prescribed in the Japan Industrial Standard (JIS), that is, excellent in temperature stability of the electrostatic capacity, having a good insulation resistance value, relative dielectric constant, or other characteristics, and having a long accelerated life of the insulation resistance.

1 . A method of producing a ceramic material powder comprised of main ingredient particles made of barium titanate having on their surface a covering layer made of a secondary ingredient additive, comprising:
 a step of preparing a mixed solution of powder-state main ingredient particles and a solution-state secondary ingredient additive and   a step of heat treating said mixed solution,   a treatment temperature and treatment time of said heat treatment being changed to control an average thickness “Δr” of said covering layer to a range of 0.015 r to 0.055 r with respect to an average radius “r” of said main ingredient particles.   
     
     
         2 . A method of producing a ceramic material powder comprised of main ingredient particles made of barium titanate having on their surface a covering layer made of a secondary ingredient additive, comprising:
 a step of preparing a mixed solution of powder-state main ingredient particles and a solution-state secondary ingredient additive and   a step of heat treating said mixed solution,   a treatment temperature and treatment time of said heat treatment being changed to control an average thickness “Δr” of said covering layer to a range of r(α−β) to r(α+β) with respect to an average radius “r” of said main ingredient particles (where the values of α and β are constants determined by the composition of the main ingredient particles, the type of the secondary ingredient additive forming the covering layer, etc.).