LOW Z COATINGS FOR FUSION-REACTOR APPLICATIONS

A large number of potential coating and substrate materials for tokamak fusion reactor components have been evaluated as to their erosion rates under low energy (250-1000 eV) hydrogen ion bombardment. For further testing, promising candidate coating materials have been deposited by chemical vapor deposition (TiB2, TiC and B4C) and plasma spraying (Be, TiB2, TiC and VBe12) onto metal and graphite substrates. The adherence of the coatings has been evaluated in pulsed electron beam heating experiments. A number of coating-substrate combinations have survived 30-50 one second pulses of heating at power densities of 2 kW/cm without apparent damage. Others fail by thermal stress induced spall, coating-substrate alloying reactions and/or substrate melt. © 1979.