Microwave dielectric properties and chemical resistance of low-temperature-sintered CaZrB₂O₆ ceramics

Dolomite-type borate ceramics consisting of CaZrB₂ O₆ were synthesized via a conventional solid-state reaction route; low-temperature sintering was explored using Bi₂ O₃-CuO additives of 1-7wt% for low-temperature co-fired ceramics applications. For several sintering temperatures, the microwave dielectric properties and chemical resistance of the ceramics were investigated. The CaZrB₂O₆ ceramics with 3wt% Bi₂O₃-CuO addition could be sintered below 925°C, and the microwave dielectric properties of the low-temperature samples were ε_r = 10.55, Q × f = 87,350GHz, and τ_f = + 2 ppm/°C. The chemical resistance test result showed that both CaZrB₂O₆- and Bi₂O₃-CuO-added CaZrB₂O₆ ceramics were durable in basic solution but were degraded in acid solution.