Effect of Heat Treatment and Bath Composition of Electroless Nickel-Plating on Cavitation Erosion Resistance

Abstract

Electroless Nickel-Phosphorus coatings have had a lot of interest in various industries due to outstanding characteristics. Some of the highlighted characteristics of electroless Ni-P coatings are superior corrosion and wear resistance. But the effectiveness of electroless Ni-P coating in resisting cavitation damage is not studied so well and is not so clear. In the present investigation, electroless Ni-P coatings were prepared at various conditions including the type of bath, heat treatment temperature and plating solutions composition. The properties of electroless Ni-P coatings were characterized using X-ray diffraction technique (XRD), energy dispersive X-ray (EDX) optical microscope, and microhardness tester. The cavitation erosion tests were carried out to study the effect bath type, heat treatment temperature and plating solutions composition on the deposit coatings.The XRD results indicate that the as-deposit had crystalline structure for alkaline bath and amorphous structure for acid bath. Heat treatment of the coatings produced mixture of polycrystalline phases. The thickness of deposit films depend on the bath type and concentration and were the least for alkaline baths. Maximum hardness of heat treated samples was found to depend on the solution composition and occurs at temperature 300 °C and 400°C.The highest erosion resistance of the coatings was observed for the heat treated deposits at temperature of 650 °C, and comes to the fore the coatings formed in alkaline baths followed by that formed in acid baths. The best erosion resistance for deposits formed in alkaline baths is attributed to the small thickness and crystalline structure. The results showed also that the cavitation erosion resistance is independent on surface hardness.

Optimizing Heat Treatment for Electroplated NiP and NiP/SiC Coatings

“…According to the results of Sribalaji et al [44], if the plastic work fraction (W P /W T ) is more than 0.5, such materials are considered to be ductile materials that deform plastically and produce more pile-up. The fraction of plastic work can be determined by Equation (3).…”

“…NiP coatings have mainly been produced by electroless deposition, which can deposit a uniform coating on samples with recesses and complex geometry [1][2][3]. However, there are some challenges in controlling electroless nickel-plating solutions.…”

Artificial neural network model for evaluation the effect of surface properties amendment on slurry erosion behavior of AISI 5117 steel

“…Among these techniques, electroless plating and carburizing have been widely used. The electroless coating has widely used in industrial application because of its ability to produce hard coating that possesses outstanding wear, corrosion and frictional resistance and hardness (Karrab et al , 2013; Rabizadeh et al , 2010; Saleh, 2013).…”