The tribological characteristics of electroless NiP coatings

The utilization of electroless NiP (EN) coating process in various industries such as printing, textile, oil and gas, food, electronics, automotive, aerospace, chemical, and mining has witnessed a tremendous increase during the last few decades. The endearing characteristics of EN coatings include excellent corrosion and wear resistance, superior mechanical and electrical properties, uniform coating thickness, and outstanding surface finish properties. In the present work, samples of 1018 substrate having various levels of surface roughness were coated with low, medium, and high phosphorus EN coatings. The different substrate surface morphologies were obtained using different machining parameters. The effects of EN coatings on the tribological and morphological properties of the substrate material were investigated using surface roughness and hardness measurements, wear and coefficient of friction tests, optical microscopy (OM), and scanning electron microscopy (SEM). It was found that the surface roughness characteristics of substrates can be enhanced and their coefficients of friction (COFs) significantly altered by EN coatings. The results further showed that, unlike conventional electroplated deposits, EN coatings do not subvert the substrate surface shape and profile even for large thickness coats. It was also found that the wear resistance of EN coatings is significantly affected by heat treatment. (C) 2001 Elsevier Science B.V. Ah rights reserved.