A Mo-Si-B based coating was applied to niobium that produced a coating structure composed of molybdenum and niobium silicides. Oxidation tests at 1000 degrees C and 1200 degrees C showed that the Mo-Si-B coating provided enhanced oxidation protection of niobium due to the formation of a protective aluminosilica layer. The coating performance was identified to be limited by the formation of NbB2 during the pack cementation process. A revised coating treatment was implemented using TiB2 as the boron source to reduce the NbB2 formation. The Mo-Si-B coating utilizing plasma spray deposition of Mo and a revised pack cementation exhibited a mass change of 0.44 mg cm(-2) after TGA testing at 1300 degrees C for 24 h.
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