THE STRUCTURE, PROPERTIES AND PERFORMANCE OF PLASMA-SPRAYED BERYLLIUMFOR FUSION APPLICATIONS

Plasma-spray technology is under investigation as a method for produci ng high thermal conductivity beryllium coatings for use in magnetic fu sion applications. Recent investigations have focused on optimizing th e plasma-spray process for depositing beryllium coatings on damaged be ryllium surfaces. Of particular interest has been optimizing the proce ssing parameters to maximize the through-thickness thermal conductivit y of the beryllium coatings. Experimental results will be reported on the use of secondary H-2 gas additions to improve the melting of the b eryllium powder and negative transferred-are cleaning to improve the b onding between the beryllium coatings and the underlying surface. Info rmation will also be presented on thermal cycle tests which were done on beryllium coated ISX-B beryllium limiter tiles using 10 s cycle tim es with 60 s cooldowns using a heat flux slightly in er;cess of 5 MW/m (2).