Abstract
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 thick coatings which present moderate adhesion to the substrate and show porosity and formation of oxide interlayers, which impairs to obtain full benefits of the coatings properties. 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. It is demonstrated by a Life Cycle Assessment (LCA) that this process is clean. Moreover, the corrosion resistance of as-sprayed and in situ remelted layers was evaluated by potentiodynamic polarization curves. The corrosion resistance was increased because of the finer structure and higher densities of the coatings, nevertheless, corrosion mechanisms occurring in all cases are different.
