Analysis of Different High-Velocity Thermally Sprayed Coatings to Recover AISI H13 High-Pressure Die Casting Molds

Abstract

High-pressure die casting (HPDC) is a manufacturing process used in the automotive sector to make high-precision components. Corrosion induced by molten metal and heat-checking cracks are two of main failure modes for die casting molds, changing the die's geometry and surface quality. Thermally sprayed coatings can improve the surface properties and recover the geometry of the die caused by aluminum attack. The main objective of this work is to observe the behavior of the H13, Cr₃C₂-25NiCr, and WC10Co4Cr coatings deposited by HVOF and HVAF processes in aluminum corrosion and die soldering tests. During corrosion and die soldering tests, chromium carbide in the Cr₃C₂-25NiCr coating reacts with the molten aluminum, creating a tough intermetallic interface and raising the extraction stress. After tests, it was observed that the WC 10Co 4Cr HVAF coating presented low adhesion to aluminum with no observed coating failure due to the formation of intermetallic. Die soldering tests indicated that the WC 10Co 4Cr coating protects the substrate, resulting in lower extraction stress than H13 base material and other HVOF coatings. It was observed that WC 10Co 4Cr HVAF coating showed results comparable to AlCrN PVD coating.