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Blistering of plasma coated aluminium castings
(-----) January 4, 2008
We face blister problem on aluminium pressure die casted components which are plasma coated . the problem occurs after a period of one or two years. your expert advice is requested to overcome this problem.Sundhareshwaran
employee - Coimbatore, Tamilnadu, India
January 16, 2008
Probable causes include:
1- Corrosion of the aluminum substrate from exposure to environment though porosity in the coating (remember plasma coatings exhibit around 5% porosity).
2- Difference in the thermal expansion coefficients of both materials will gradually tend to separate the coating.
Remedies could come from thinner but more dense coatings like new generation of HVOF equipment or PVD coatings.
Monterrey, NL, Mexico