Thermal stable microwave dielectric properties of CdWO4 ceramics prepared by high energy ball milling method.

The CdWO 4 powders were synthesized by using a high energy ball mill method, and microwave dielectric of (1−x)CdWO 4 –xTiO 2 (0 ≤ x ≤ 0.22) composite ceramics have been investigated. X-ray powder diffraction and SEM analysis revealed that CdWO 4 and TiO 2 coexisted as a mixture. With addition of nanometer TiO 2 , the sintered temperature of CdWO 4 ceramic was reduced from 1025 °C to 900 °C. With increase of x, the Q × f values of (1−x)CdWO 4 –xTiO 2 ceramics decreased and the ε r values increased. The τ f value depends on x as well as sintering temperatures. The ceramics of 0.79CdWO 4 –0.21TiO 2 sintered at 900 °C showed ε r = 13.7, Q × f = 15000 GHz, τ f = 0 ppm/°C and the chemical compatibility with Ag make it suitable as LTCC dielectric devices. [ABSTRACT FROM AUTHOR]