Reactive consolidation/sintering

The high melting point and reactivity of tantalum with the permanent gases at high temperatures prevents conventional consolidation by melting and casting in air. The metal is in fact consolidated by vacuum sinter-... 

The very chemically reactive plutonium hydride is usually decomposed in a vacuum-tight furnace capable of attaining a temperature of 700°C. Plutonium hydride that is decomposed under vacuum at temperatures below 400°C forms a very fine (<20y) metallic powder above 500°C the powder begins to sinter into a porous frit which melts at 640°C to form a consolidated metal ingot. This metal typically contains significant oxide slag but is suitable for feed to either molten salt extraction or electrorefining. 

The majority of these refractory materials have been prepared following the classical electric current activated sintering approach, i.e. starting from previously synthesized UHTC powders. Nevertheless, some attempts to synthesize and simultaneous consolidate these ceramics through the so-called reactive spark... 

---