The Relationship Between Toughness With Grain Size And Distribution In Piezoelectric Ceramic

Piezoelectric ceramic as an important sensitive functional material of force, heat, electricity and light, which has become important ceramic materials in the industrial, research and daily life. Piezoelectric ceramic not only has good piezoelectric properties, but also has good mechanical properties. Piezoelectric ceramics has low fracture toughness which limits its practical application scope, so how to improve the fracture toughness of piezoelectric ceramics becomes very challenging research topic.Firstly, this paper analyzes and summarizes the piezoelectric ceramic fracture behavior and toughening mechanism, The following conclusions are easy to draw:For the transgranular fracture of piezoelectric ceramics, the main toughening mechanism is micro-crack toughening, porosity have a negative effect on toughness; For intergranular fracture of piezoelectric ceramics, the main toughening mechanism is the dissociation of grain boundary, porosity also has a negative effect on the toughness. Then, the paper analyzed the typical experimental phenomena and various interpretations which were existing. Introducing the second phase to toughening piezoelectric ceramic, which significantly improves the piezoelectric ceramic fracture toughness and inevitably, but seriously damages piezoelectric properties. However, the self-toughening piezoelectric ceramic not only improve the fracture toughness, but also maintains its excellent piezoelectric properties. According to the above conclusions, this paper based on the piezoelectric ceramic's self-toughening, without changing the piezoelectric properties, created a model that the piezo-electric ceramic's fracture toughness on the effect of grain size and distribution.The paper uses the model established to calculate BaTiO3,PZT and (Bi1/2Na1/2)TiO3 Piezoelectric. It is easy to find that the different of grain size and distribution have a significant impact on fracture toughness, and it was calculated that piezoelectric ceramic's fracture toughness with different content of large particles. we find that the calculated result is consistent with that of experiment. which proves the model's reliability and general applicability. In the future, we can use the model to solve the optimal grain size and distribution, and prepare the best piezoelectric ceramic.