Thermal fatigue properties of coated materials for fusion device applications

Abstract

The adherence of plasma sprayed coatings of TiC, VC, TiB 2 and B on substrates of Cu, 316 ss, Mo, Ta and Poco AXF-5Q artificial graphite has been evaluated in a pulsed electron beam, thermal fatigue environment. The materials are candidates for application as limiter and armor components of tokamak fusion devices. Up to 500 cycles of heating at power densities of 1.5 kw/cm 2 for 1.5 sec. were used. Materials were tested both in the as-sprayed (19–33% porosity) condition and after hot isostatic pressing (HIP) to increase coating density. Some (e.g. TiC on Mo and Ta) showed good survivability in both the as-sprayed and HIP densified conditions. TiB 2 on Mo and Ta and VC on Poco graphite were improved while TiC + V on Mo and Ta were degraded by the HIP treatment.