Use of Duplex PVD Coatings to Increase the Life of Moulds and Cores for die Casting of Aluminium Alloys in the Automotive Industry

Abstract

The paper presents the results of research aimed at increasing the life of moulds and cores for high-pressure aluminium casting. The castings produced are intended for the automotive industry. Local impulse heating was applied to the surface of the base material of the Uddeholm Dievar moulds. Three heating rates were used. After surface treatment, structural analysis was performed. PVD coating nACRo3 was applied to the surface treated in this way. Coating deposition was performed by Larc technology. The quality of the coating was evaluated on the basis of the Scratch test and the Mercedes test. After laser treatment of the material surface and application of nACRo3 coating, the surface microgeometry was evaluated according to ISO 25 178. The coated surface was then immersed in an Al - Si-based alloy melt at a temperature of 680 ± 20°C and remaining in the melt for 120 and 300 min. Experimental work has confirmed that the resistance of the mould surface has significantly increased.