摘要
The effects of Li 2 O-B 2 O 3 -SiO 2 (LBS) glass addition on densification and dielectric properties of (Ca 1−x Sr x )(Zr 1−y Mn y )O 3 fired in a reducing atmosphere have been investigated. The dielectric properties of (Ca 1−x Sr x )ZrO 3 become better with decreasing the ratio of Sr/Ca. Substituting Zr by 0.2 mol Mn, the dielectric loss of (Ca 0.9 Sr 0.1 )ZrO 3 is greatly reduced, resulting in a Q × f r value of 30500 GHz. To reduce the densification temperatures of (Ca 0.9 Sr 0.1 )(Zr 0.8 Mn 0.2 )O 3 (CSZM9182) to the range cofirable with Cu electrode, 5–10 vol% LBS glass is added and the densification temperature is lowered from 1500 °C to 1030 °C. The densification is further enhanced with increasing [B 2 O 3 ]/[SiO 2 ] ratio in the LBS glass, however, the dielectric properties are deteriorated. The above result is attributed to a chemical reaction taking place at the interface of CSZM9182-LBS during firing, which becomes more extensive with increasing [B 2 O 3 ]/[SiO 2 ] ratio in the LBS glass and tends to form a second phase of CaZr 4 O 9 . For the LBS glass with 40 mol% Li 2 O, 20–50 mol% B 2 O 3 , and 10–40 mol% SiO 2 the resulting CSZM9182 +5–10 vol% LBS microwave ceramics have a dielectric constant of 23–27, Q × f r value of 2500–22,000 GHz at 7.6–7.8 GHz, and a temperature coefficient of resonant frequency (τ f ) of −22~ −7 ppm/°C in the temperature range between 25 °C and 80 °C.