Investigation of thermal diffustivity for nano-phase composite ceramics

摘要

In recent years, there has been increasing interest in nanostructured ceramic materials becuase of their advanced properties. The superplasticity; improved strength and toughness, higher densification rate and low sintering temperature are observed in these materials [1-4]. The sintering speed v_(sintering) of ceramic is relatd to the grain size d by the expression of v_(sin ting) propor.to d~(-4) [2]. adding the nano-particles of Al_2O_3 to conventional Al_2O_3, the strength, fracture toughness and thermal resistance of Al_2O_3 ceramic can increase[5]. Up to now, only a few researchers[6,7] have concerned about the specific heat and thermal expansion of nano-ceramics, and no report about thermal diffusivity of nano-composite has been found in literature. However, characterizations of thermal diffusivity of nano-compossite ceramics are very important for designing and preparing this kind of new materials.