Fabrication, sinterability, and mechanical properties of lead zirconate titanate/silver composites

High-toughness and high-strength lead zirconate titanate (PZT) composites t hat contain fine silver particles were successfully fabricated at low sinte ring temperatures. Addition of silver to a PZT matrix did not result in unw anted reaction phases; however, some silver diffused toward the perovskite crystal structure. A small quantity of silver accelerated the sinterability of the PZT composites. The formation of oxygen vacancies due to the partia l substitution of silver appeared to enhance the sinterability of the PZT, Fracture toughness depended on the size and degree of sphericity of the sil ver particles, and SEM observations on crack propagation suggested that the toughening mechanism in the PZT/Ag composites involves crack bridging resu lting from the ductile behavior of silver particles. It is proposed that hi gh fracture strength in PZT/1 to 5 vol% Ag composites results from the rela xation of transformation-induced internal stress by the silver particles.