Chemical stripping of ceramic films of titanium aluminum nitride from hard metal substrates

We report here the result of a study of different chemical stripping methodologies for ceramic coatings deposited by PVD on hard metal substrates. We show that an approach based on the study of the system by surface science techniques leads to the possibility of developing effective stripping methods as well as guidelines for improving the process. We will report about two methods tested for the stripping of layers of titanium aluminum nitride (TINALOX) deposited by Physical Vapor Deposition (PVD) on hard metal substrates. The methods were based on (i) the combination of hydrogen peroxide and potassium oxalate in alkaline conditions, and (ii) potassium permanganate in a concentrated sulfuric acid solution. Of the two methods, the second (permanganate and sulfuric acid) appears to be the most promising, although further studies will be needed to optimize the process.