Abstract: The effects of WO3 additive on the phase composition, microstructure, sintered properties and dielectric properties of Ba4Sm9.33Ti18O54 (BST) microwave dielectric ceramics which prepared by conventional solid-state route were investigated.The results show that moderate addition of WO3 can produce the lattice defects and promote ion diffusion by the inequivalent ion replacing Ti-site, Thus effectively lower the sintering temperature which dropped to 1280 ℃, but also reduce the generation of oxygen ion vacancy, decrease the dielectric loss.At the same time, the new phase BaWO4 was generated, which also help to improve the dielectric properties.The 0.25wt; WO3-doped BST ceramics sintered at 1280 ℃ for 3 h have the optimal integrated microwave dielectric properties: εr=80.4, Q·f=11740.85 GHz, Υf=-23.3×10-6 /℃.

Key words: The effects of WO3 additive on the phase composition, microstructure, sintered properties and dielectric properties of Ba4Sm9.33Ti18O54 (BST) microwave dielectric ceramics which prepared by conventional solid-state route were investigated.The results show that moderate addition of WO3 can produce the lattice defects and promote ion diffusion by the inequivalent ion replacing Ti-site, Thus effectively lower the sintering temperature which dropped to 1280 ℃, but also reduce the generation of oxygen ion vacancy, decrease the dielectric loss.At the same time, the new phase BaWO4 was generated, which also help to improve the dielectric properties.The 0.25wt; WO3-doped BST ceramics sintered at 1280 ℃ for 3 h have the optimal integrated microwave dielectric properties: εr=80.4, Q·f=11740.85 GHz, Υf=-23.3×10-6 /℃.