Owing to gas velocities in the super-sonic regimen in combination with moderate flame temperatures, the HVOF processes are preferred for the deposition of wear and/or corrosion resistant carbides as well as Hastelloy, Triaballoy and Inconel alloys. The resulting coatings have usually very high bond strengths, fine as-sprayed surface finishes and low oxide levels. However, the generation of a supersonic flow of combustion products supposes the implementation of relatively high gas flow rates and high energetic gas mixtures, which are intrinsically associated with high production costs, limiting the application of this technology in some industrial fields. This work summarises the first results in the development of a prototype aimed to show the potential of a new thermal spray technology named Oxy-Fuel Ionisation spraying for the development of high quality carbide base coatings. The OFI process is a supersonic combustion process as well, enhanced by the addition of ionised gas specimens. The arising combustion process is characterised by its stability within a broader range of the “fuel/oxidant” correlation in comparison to conventional HVOF systems, because of the presence of ionised gas specimens which are acting as a catalyst. It has been proved that this developed prototype allows the thermal spray deposition of carbide based materials with relatively low oxygen flow rates. For comparison two different coating materials were investigated, WC-17Co and Cr3C2-NiCr. The process parameters were optimised in terms of the micro hardness, the porosity and the decarburization of the resulting coatings.

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