Fabrication of SiCAlN/Mo functionally gradient material for high temperature use

The powder metallurgical fabrication of a SiCAlN/Mo functionally gradient material for thermal barrier use is described. Molybdenum was used as a host material to share structural strength and joining capability. To obtain basic knowledge for the thermal barrier function, a detailed investigation was carried out for the determination of the compositional dependence of the thermal and mechanical properties in the SiCAlN ceramic alloy system. The results have shown that the samples HIPed at 2123 K at 200 MPa for 2 h from mixture of SiC and AlN powders have more sufficient thermal barrier properties with high fracture strength at elevated temperature than monolithic SiC and AlN. The designing of the compositional distribution with respect to the overall heat transfer in a temperature difference of 1000 K was studied. With an optimum compositional distribution, a sintered compact of functionally gradient material of SiCAlN/Mo was successfully fabricated.