Metal—ceramic functionally gradient material for insulation pipe joint in fusion environment

Abstract

A stainless steel/ceramics/stainless steel functionally gradient material (FGM) has been developed for an integrated insulation joint of the piping system. Both sides of the joint unit are welded to the main pipes. 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 sintering process. The producible conditions, e.g., the thickness of graded layer, the column diameter, the materials combination and the sintering temperature and pressure, have been established. The performance tests of FGM joint, i.e., electrical property, mechanical property, vacuum tightness property and neutron irradiation effect were carried out. The results of those tests say that the FGM joint capable of providing the electrical insulation of cooling pipes for vacuum use.