Experimental research of Cr-Ag coatings prepared by magnetron sputtering and electroplating for ITER thermal shield

The Cr-Ag coating was prepared by electroplating and magnetron sputtering on 6061 aluminum alloy matrix to balance the thermal shield radiation shielding capability and the coating performance for the International Thermonuclear Experimental Reactor (ITER) project. The microstructure, adhesion, and thermal shielding properties of the coating were analyzed. The results show that the Cr-Ag magnetron sputtering coating has flat surface, and better thickness uniformity than electroplate coating. The adhesion force of the Cr-Ag magnetron sputtering coating is 1.56 times higher than that electroplating coating, which is 53 N. The emissivity test results show that the emissivity of Cr-Ag coating by magnetron sputtering method at 80 K is 0.018, much lower than the emissivity of electroplating coating and 6061 aluminum alloy matrix. Theoretical calculation of radiant heat load based on emissivity test shows that the thermal shielding effect of Cr-Ag coating on thermal shield surface by magnetron sputtering is better than that of other groups. The results are of great significance for the combination of coating properties with broader thermal shield properties.