Properties of Hard Ni–P–Al2O3and Ni–P–SiC Coatings on Al-Based Casting Alloys

In the present work, electroless Ni–P–Al2O3 and Ni–P–SiC composite coatings on an aluminium-silicon casting alloy are studied. A suspension containing nickel lactate, nickel hypophosphite, lactic acid, water, and dispersed ceramic particles was used for the electroless deposition. The structural study, hardness, and abrasion tests reveal that properties of the coatings strongly depend on the composition of deposition bath and on the heat treatment. The composite coatings heat treated at 400°C/1 h showing outstanding abrasion resistance are promising candidates for surface protection of light components.