Investigation of the Mechanical Properties of Electroless Nickel Coatings Deposited on an ABS Substrate at Different pH Levels

Two nickel coatings—with plating-bath pH values of 3.8 and 4.8 and thicknesses of 9.38 μm and 4.88 μm, respectively—were chemically deposited onto ABS (acrylonitrile butadiene styrene) substrates with a thickness of 2040 μm. ABS is a plastic widely used as a structural material. Various types of components—formerly made of metal but now produced from ABS plastic to save metal and reduce structural weight—can be easily extruded or, in certain cases, molded. Nanoindentation experiments were conducted on the two nickel coatings and the ABS substrate using the XP head and CSM module of a G200 nanoindenter (KLA Corporation, Milpitas, CA, USA), alongside an “Express test” on the substrate. The substrate’s influence on the film’s indentation modulus was eliminated using the Hay-Crawford analytical model. Moreover, wear resistance tests were performed on the coatings, with the sample surfaces scanned using the NanoVision module both before and after the tests. The influence of the plating-bath pH on the mechanical properties of the investigated coatings was evaluated. It was found that with increasing plating-bath pH of films, their indentation hardness and indentation modulus decrease.