Fabrication and properties of functionally gradient materials

Abstract

Functionally Gradient Materials (FGMs) characterized by the material having continuously varying material property from one surface to the other, have been prepared using gas, liquid or solid as starting material via several methods such as CVD, PVD, ion plating, plasma spraying, sintering or self-propagating high temperature synthesis. The initial research in the development of the Functionally Gradient Materials was to obtain a superior thermal resistant composite material having excellent thermal barrier characteristics, thermal resistance and thermal stress relaxation, however, the recent trend in the development study is to consider FGM as a possible material superior in not only thermal characteristics but also in electrical, optical and chemical functions. In the application of Functionally Gradient Materials for the thermal barrier material the concentration of the dispersion phase is gradually varied in the material to obtain the required thermal stress relaxation.