Tdk Corporation

Tetsuo Akoh

Toshihiro Suzuki

Hiroshi Tsuyuki

Kentaro Sawamura

Yoshishige Towatari

A copper electrode is firmly bonded to a sintered ceramic oxide body by applying a first copper film on a ceramic oxide body by electroless plating or vapor phase plating such as evaporation or sputtering, forming a second copper film thereon by electrolytic plating, and heat treating the copper films on the body at a temperature of 750.degree. to 1065.degree. C. in a weakly oxidizing atmosphere.

Formation of copper electrode on ceramic oxide

A copper electrode is firmly bonded to a sintered aluminum nitride body by applying a copper film on a sintered aluminum nitride body by electroless or electrolytic plating, evaporation or sputtering, and heat treating the copper film on the body at a temperature of 900.degree. to 1083.degree. C. in a weakly oxidizing atmosphere.

Formation of copper electrode on aluminum nitride

An improved dielectric resonator for high frequency operation having improved unloaded Q is provided which is prepared by forming a first copper coating on the ceramic body to a thickness of 0.2 to 1 .mu.m by electroless plating or vacuum deposition, electrolytic plating a second copper coating on the first coating to a thickness of at least two-fold of the skin depth, and heat treating the thus coated body at 120.degree.-300.degree. C. in a reducing atmosphere or at 700.degree.-1080.degree. C. in a weakly acidic atmosphere.

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Tokyo, Japan

Tetsuo Akoh