FABRICATION OF TI CARBIDE DISPERSION COMP OSITE COATINGS BY PLASMA SPRAYING OF MA POWDERS

Composite powder materials possess a potential to fabricate the high p erformance structural coatings instead of the conventional mechanicall y mixing powders. In the many composite powder making processes, macha nical alloying (MA) process enables to obtain the homogeneous microtru cture of metal/ceramic materials system. In the DC plasma spraying of metal/ceramic MA composite powders, separation phenomena of ceramic ph ase from metal phase has been recognized. In this study, metal/ceramic MA composite powders were made by using the ceramic making original e lements as the starting material and these MB powders were plasma spra yed. Possibility of fabrication of ceramic particles dispersed composi te coatings, by the inter-diffusion of these starting elements, was in vestigated. The main results obtained in this work are summarized as f ollows: (1) Separation was recognized even in the Cu/TiC MA powder mat erial system, which had good wettability between metal and ceramic mat erials. (2) Separation is basically caused in MA composite powder mate rials under the spraying conditions of high power level, on which both materials can be fully melted. (3) TiC dispersed homogeneous coating was made by DC plasma spraying of Cu/Ti/C MA powder. (4) Coating made from MA powders showed slightly higher hardness with less scattering c ompared with that made from the conventional powders, because of the h omogeneously dispersed structures.