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

The ion substitution with Mn 4+ and W 6+ co-substituted Nb 5+ in B site of a low firing Bi 2 O 3 -ZnO-Nb 2 O 5 -based A 2 B 2 O 7 pyrochlore ceramics was investigated. The Mn 4+ and W 6+ co-substitution was tentatively introduced in cubic-monoclinic pyrochlores co-existing ceramics Bi 3x Zn 2-3x (Zn x Nb 2-x-2y Mn y W y )O 7 (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 Mn 4+ and W 6+ substituted Nb 5+ 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 Mn 4+ and W 6+ 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.