New vacuum plasma spray-forming technology combined with post-spray heat treating produces near-net-shape refractory metal components with very efficient material utilization and the elimination of post-fabrication machining.
High temperature furnace components used for microgravity processing in space are made of refractory metals, taking advantage of their high melting temperatures and inherent chemical stability. Techniques were developed to produce near-net-shape refractory metal components using vacuum plasma spraying (VPS), a process wherein material utilization is very high, and laborious machining can be avoided. As-spray-formed components performed adequately, but higher mechanical and thermal properties were needed. Properties were improved via post-processing thermal treatments such as hydrogen sintering and vacuum annealing. Components were made of tungsten, rhenium, tantalum, niobium and molybdenum refractory metal alloys.