Mn4+ and W6+ substitution on Bi2O3–ZnO–Nb2O5-based low firing ceramics

The ion substitution with Mn4+ and W6+ co-substituted Nb5+ in B site of a low firing Bi2O3–ZnO–Nb2O5-based A2B2O7 pyrochlore ceramics was investigated. The Mn4+ and W6+ co-substitution was tentatively introduced in cubic-monoclinic pyrochlores co-existing ceramics Bi3xZn2−3x(ZnxNb2−x−2yMnyWy)O7 (x=0.5–0.65, y=0, 0.02, 0.05, 0.1) and the results shows interested regular influence on the structure, dielectric properties with the amount of substitution amount change. With the structure evaluation and electrical properties measurement results, the Mn4+ and W6+ substituted Nb5+ in B site shows effective to depress the grain growth and the ceramic with fine grains in 1–3 μm can be obtained. The electrical properties was also enhanced in smaller substitution amount but degraded with the substitution amount increasing. Based on these results, small amount of Mn4+ and W6+ substitution was successfully applied to a base ceramic with the electrical properties satisfied the NP0 specification to miniaturize the grains and enhance the sintering behavior.