Sintering behavior and dielectric properties of BZN ceramic powders coated by CuSO4

(Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 (BZN) ceramics were synthesized by the traditional solid-state reaction method. Copper oxide is known as a good sintering aid for microwave dielectric ceramics and to be less reactive toward silver. We have introduced the CuO into BZN by modifying BZN surface by a CuO thin layer on the calcined powder instead of mixing CuO directly with BZN powder. A CuO precursor solution of CuSO4, was used to prepare the CuO thin layer. This paper describes the effect of CuO layer on the sintering behavior, phase composition and dielectric properties of BZN ceramics. The results showed that appropriate CuO addition could accelerate the sintering process and lower the densification temperature to 900 degrees C. The optimal concentration of CuSO4 was found to be 0.5M. The BZN ceramic sintered at 900 degrees C presented good microwave dielectric properties i.e. epsilon(r) = 141 and QF = 426 GHz, which is much better than those of CuO doped BZN ceramic (epsilon(r) = 134 and QF = 287 GHz).