In studies of erosion-corrosion of materials in aqueous conditions, there have been a few attempts to evaluate the performance of coatings. This is despite the fact that the use of coatings provides a relatively economic method of reducing erosion-corrosion damage in such environments. There has also, as a consequence, been no attempt to define a rationale for coating selection for exposure to various erosion-corrosion environments.
The object of this work has been to address the above issues by investigating the effect of increasing velocity on a range of physical vapour deposition (PVD) coated and uncoated steels, at various applied potentials, in a carbonate/bicarbonate slurry solution containing alumina particles. The performance of two coatings, Ti2N and CrN was evaluated. The results were compared to those for the uncoated steel (mild steel) and 304 stainless steel,
The results showed that the both the corrosion and passivation potentials for the coatings occurred at different values for the individual coatings. Hence, the erosion-corrosion "regime" maps differed for the different coating systems. Materials performance maps were constructed from the results, providing a basis by which the use of such coatings may be optimized for exposure to aqueous erosion-corrosion conditions. (C) 1999 Elsevier Science S.A. All rights reserved.
- PVD coatings