Performance enhancements of die casting tools trough PVD nanocoatings

Wear and failure of die casting dies involve a complex interaction between various mechanisms. The most important wear and failure modes are summarized as follows: (i) the so-called washout damages on working die surfaces are attributed to erosion, corrosion and soldering; (ii) thermal fatigue is the most important failure mode in die casting. The sector of surface thin PVD coatings is constantly enhancing in order to meet the increasing demand for improved performances of tooling. Advanced PVD coatings are designed to withstand severe mechanical and thermal stress conditions. A CrAlSiN nanostructured coating system was deposited on the base material, modulating the chemical composition so as to increase either the chromium or the aluminium-silicon content. Then, another set of specimens was subjected to a cyclic immersion program in a molten aluminium bath. The washout signs were detected and monitored in function of the increasing number of cycles.