CERAMIC-METAL COMPOSITES BY ELECTROPHORETIC DEPOSITION AND SINTERING

摘要

Functionally graded materials (FGM) are a promising class of materials for a broad range of industrial applications. In automotive industry, graded composites for claddings, exhaust valves, coatings for tribological applications, electronic circuitry components are examples of the potential usage of FGM where gradual spatial distribution of material composition is essential for solving the problem of thermomechanical properties mismatch. Due to the inherent nonuniformity of properties, the fabrication of functionally graded materials offers substantial challenges. In particular, during sintering a differential shrinkage can lead to distortions and damage of produced components. In the present study a mathematical model for microwave sintering of functionally graded composites is developed. Based on the model, the evolution of sintered macroscopic shape is predicted. The modeling effort is supported by experiments on microwave sintering of green parts shaped by electrophoretic deposition. Alumina/zirconia material system it is shown that microwave sintering of graded composites provides both high process efficiency and high final relative density.