PURPOSE: To reduce costs and to improve a Q characteristic by means of the base-metal operation of an electrode material and simplification of processes by forming an electrode layer by means of electroless copper plating through a medium layer consisting of a noble metal ultra-particulate sol on the surface of a cylindrical ferroelectric ceramic sintered body.
CONSTITUTION: The edge part of an element is made round by barrel-polishing a ceramic sintered body 4, etc., and the whole surface is made rough by etching- treatment in a hydrofluoric acid solution. Next, the cylindrical ceramic sintered body 4 is dipped to the catalytic solution consisting of the noble metal ultra- particulate sol, and a catalytic layer 6 is deposited on the whole internal and external surfaces of a through hole 5, or deposited to the selective surfaces by applying resist to the surfaces as needed. Then the body is dipped to the electroless copper plating solution consisting of the alkali solution of copper complex salt and formalin, the metal copper is deposited on the surface of the medium layer 6 consisting of the noble metal ultra-particulate sol to the width 5 to 10μ to form an electrode layer 7. Thus, the electrode layer 7 excellent for uniformity and adhesiveness can be formed on the surface of the sintered body 4.
MATSUI TOSHIKI
MAKINO YOSHIYUKI
HISADA NOBORU
YAMADA MISAO
UENISHI KENJI
TODA KOGYO CORP