Alumina-based ceramic composition

Abstract

Abstract A sintered alumina-based ceramic body exhibiting excellent electrical characteristics, in particular, excellent dielectric power factor and a temperature coefficient of a resonant frequency, which consists essentially of 0.01 to 7 parts by weight of Ta 2 O 5 admixed with 100 parts by weight of an expanded Al 2 O 3 --SnO 2 --TiO 2 ternary base composition (by molar fraction) of: ______________________________________ Al 2 O 3 SnO 2 TiO 2 ______________________________________ 0.925 0.055 0.020 0.625 0.285 0.090 0.625 0.0245 0.3505 0.925 0.010 0.065 ______________________________________ Dielectric power factor tan δ of 10×10 -5 or below and temperature coefficient (Tf) of the resonance frequency from -28 to +14 ppm/° C. Tf=0 is achieved at a preferred range. An alumina-based ceramic sintered body having a compositional range within a triangular range defined by sequentially connecting the points P, Q and R in the following compositional table of the Al 2 O 3 --SnO 2 --TiO 2 ternary system, expressed in terms of the molar fraction:______________________________________Al 2 O 3 SnO 2 TiO 2 ______________________________________P 0.95 0.025 0.025Q 0.70 0.225 0.075R 0.70 0.075 0.225______________________________________ can provide the same dielectric power factor but with a temperature coefficient τ.sub.ε of the dielectric constant from -40 to +40 ppm/° C. within 1 MHz to 7 GHz.

Inventors

• 👤 Minato Ando
• 👤 Masaaki Ito
• 👤 Fumio Mizuno

Bibliographic Details