Study of multilayer and multi-component coatings deposited using cathodic Arc technique on H-13 hot work steel for die-casting applications

Abstract

Die casting process is used since long, but even today problems like erosion, corrosion, soldering and sticking affect die life. These dies undergo thermal cyclic loads from 70 ^oC to 600 ^oC during processing. Physical Vapor Deposition (PVD) hard coating can play an important role in such extreme applications. In the present work, we report the use of Chromium based multilayer CrN/Cr (M-CrN) coatings and multi-component aluminium titanium based AlTiN (M-AlTiN) coatings. The H-13 steel substrate samples were prepared using cathodic arc deposition technique. Structural properties of the coated samples were studied using XRD and SEM techniques. Tribological and mechanical properties of the coatings were studied using Calo-test and Micro-hardness test respectively. Potentiostat technique was used to study the effect of 1 M HCl solution on these coatings. Thermal fatigue (TF) test was conducted by heating the sample to around 600 ^oC and rapidly cooling it to room temperature imitating the die casting process conditions. After multiple cycles, it was observed that M-AlTiN coated samples outperform M-CrN coated samples in terms of wear, oxidation and adhesion properties. It was observed that formation of oxide layer on the coated surface during the thermal cycling inhibits further oxidation of the coating layer and result in enhanced productivity and efficiency of dies.