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2182 |
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Tuesday, May 04, 2010, Moor Room 4:00 PM HVOF 2 |
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Thermal spray processing of metal based coatings with the oxy fuel ionisation process |
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Maria Parco* / INASMET-TECNALIA , Spain Ignacio Fagoaga / Inasmet Tecnalia, Spain Georgiy Barykin / Inasmet Tecnalia, Spain |
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High velocity combustion processes are preferred for the deposition of wear and/or corrosion resistant coatings since their super-sonic gas velocities in combination with moderate flame temperatures allow the deposition of coatings with very high bond strengths, fine as-sprayed surface finishes and low oxide levels. However, the generation of a supersonic flow supposes the implementation of relatively high gas flow rates and high energetic gas mixtures, which are intrinsically associated with high production costs. Recently a novel thermal spray process, the Oxy-Fuel Ionisation (OFI), has been development and introduced to the market by Inasmet. The OFI system is basically a high velocity combustion process able to operate within the super-sonic regime using a broader range of fuel/oxidant conditions, and also with lower gas flow rates, than conventional HVOF guns. The incorporation of a low energy plasma jet in the first stage of the gun, allows the continuous addition of ionised and heated gas species to the combustion chamber, thus assisting/enhancing the combustion process and broadening its stability over a large range of gas mixtures. Previous works showed the potential of the OFI system for the production of carbide coatings, with properties comparable to those achieved with conventional HVOF systems. Nevertheless, the high flexibility of the OFI system in terms of fuel/oxidant consumption and gun modularity is expected to allow the deposition of coating materials with the most different natures. This work deals with the development of Ni-/Co- and Al-based materials, as an example of the potential of the OFI technology for the production of corrosion and wear resistant metal based coatings for different industrial applications. The process parameters as well as the system configuration have been optimised for each powder material. The results are compared in terms of the structure and micro hardness of the resulting coatings. |