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1940 |
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Wednesday, May 05, 2010, Hullet Room 12:00 PM Corrosion Protection |
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Corrosion behavior of NiCrBSi alloy coatings manufactured via in situ plasma spray laser remelting process |
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Nicolas Serres* / INSA de Strasbourg, France Françoise Hlawka / INSA de Strasbourg, France Sophie Costil/ LERMPS ? UTBM, France Cécile Langlade/ LERMPS ? UTBM, France Frédérique Machi/ IREPA LASER, France |
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Pressure to identify alternatives to hard chromium electroplating has increased these few last years, related to environmental requirements, because of the use of hexavalent chromium, a highly toxic substance. The plasma spray technique allows the formation of coatings which present low to moderate adhesion to the substrate and show porosity and formation of oxide interlayers, which impairs to obtain full benefits of the properties of coatings. In this sense, a treatment can be necessary to improve the properties of these coatings. In this paper, the effect of an in situ laser melting treatment of NiCrBSi coatings, deposited by plasma spraying was investigated. The corrosion resistance of different samples was evaluated by potentiodynamic polarisation curves, polarisation resistance and electrochemical impedance spectroscopy measurements. Laser treatment generates areas with a finer microstructure and improves also the adherence between the coating and the substrate. Moreover, this new process appears to be very suitable as another alternative to electrolytic hard chromium plating, in case of industrial applications, for corrosion protection of mechanical parts. To take into account the environmental aspect of these coatings from the point of view of the materials and the processes, a Life Cycle Assessment was established. Keywords: Plasma-laser hybrid process, Life Cycle Assessment (LCA), NiCrBSi alloy, Corrosion |