Análise da adesão de filmes depositados por PVD sobre o aço H13 com diferentes tratamentos térmicos

Abstract

Injection and aluminum extrusion molds are produced in its majority with hot work steels, amongst which one of the most utilized is the AISI H13. In order to improve the service life of the molds, surface treatments of the interior cavity. The most common treatments are nitriding or duplex, in which, after the nitriding, a PVD coating is applied. It is known that, for the nitride steel, there is an influence of the metallic substrate hardness on the wear resistance, but there are no studies about the influence of the steel hardness for duplex treatments. Manufacturers recommend ideal hardness for nitride steel, but not necessarily for duplex treatments. The following work’s objective is to analyze the adhesion difference of a PVD coating for AISI H13 steel samplesunder different tempering temperature and nitride layer thickness. It was utilized three tempering temperatures and three surface conditions, one with a nitride layer thickness of approximately 0,05mm, one with 0,09mm thickness and one without any nitriding, which had the PVD coating applied directly to the tempered steel. The PVD coating applied was the one commercially named Lumena, supplied by Oerlikon Balzers, which is composed by TiAlN. It was proved for the studied parameters that the thicker the nitride layer, the higher is the adhesion of the PVD film, and that, for the same nitride thickness, a higher substrate hardness results in a better adhesion of the coating. As secondary findings, it was perceived that the roughness has the tendency to increase after nitriding, and regularize itself with the PVD coating application.