Synthesis of thermal spray grade silicon carbide feedstock powder for plasma spray deposition

Novel synthesis of thermal spray grade silicon carbide (SiC) feedstock powder is performed to allow deposition of this material using atmospheric plasma spraying (APS) method. SiC particles with average size of 1 µm are treated using co-precipitation techniques to deliver yttrium aluminium garnet (YAG) binder from its solution precursor as nano-films onto SiC particles surface. The aim of YAG nano-films formation is to protect SiC core from direct interaction with plasma flame thus hindering decomposition and supply molten binder as matrix phase in the SiC particles vicinities. The modified SiC particles are agglomerated and sintered into 25-45µm and 45-90µm sized powder before introduced into standard feedstock delivery system. The synthesised powder shows very good flow-ability and enables successful deposition of SiC coating using APS. Both the feedstock and the produced coatings are analysed and compared with regard to their phase composition and microstructures.