delamination in the coating
We have a general delamination problem in the coatings. We have observed this problem with Ni-Graphite (flame spray), Ni-Al (flame and plasma spray) , Al-Si (plasma spray) powders. During evaluation of the microstructures we found delamination more than 0,010" close to substrate or between substrate and coating or between bond coat and top coat. All the delaminations are close to substrate, we have not found any delamination in the upper layers of coating. For abradable coatings the thickness is about 0,040-0,060 inches, for the others generally 0,020-0,035 inches.
The humidity or oil in the cooling air may cause this problem.
Does grit size effect delamination?
Does anybody have any experience with this type of problem?
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