METAL-CERAMIC FUNCTIONALLY GRADIENT MATERIAL FOR INSULATION PIPE JOINT IN FUSION ENVIRONMENT

A stainless steel/ceramics/stainless steel functionally gradient mater ial (FGM) has been developed for an integrated insulation joint of the piping system. Both sides of the joint unit are welded to the main pi pes. The FGM composed of metal and ceramics is produced by a sintering process from the powder stainless steel and powder ceramics. It is a key issue to suppress the residual thermal stress generated in the sin tering process. The producible conditions, e.g., the thickness of grad ed layer, the column diameter, the materials combination and the sinte ring temperature and pressure, have been established. The performance tests of FGM joint, i.e., electrical property, mechanical property, va cuum tightness property and neutron irradiation effect were carried ou t. The results of those tests say that the FGM joint capable of provid ing the electrical insulation of cooling pipes for vacuum use.