Role of heat treatment on the friction and wear behavior of duplex electroless nickel deposits

In the present investigation, duplex electroless Ni-P/Ni-Cu-P and Ni-P/Ni-W-P coatings are deposited on mild steel specimens using the dual bath technique. Both the coatings are developed with Ni-P as the inner layer. The scanning electron microscope (SEM), X-ray diffraction techniques (XRD) and energy dis-persive X-ray analysis (EDX) are used to characterize the duplex coatings at pre and post-heat treatment state. Heat treatment is carried out at a temperature range between 200 degrees C and 800 degrees C. The surface mor-phology of the as-deposited coatings is nodular. Grain growth and grain boundaries are clearly visible in heat treated coatings. The EDX of Ni-P/Ni-Cu-P and Ni-P/Ni-W-P coating showed the phosphorus content as 12% and 9% respectively indicating high-P deposits. The copper and tungsten content of the coatings are 10% and 3% respectively. XRD analysis of both the as-deposited coatings indicate amorphous phase while heat-treated ones have crystalline phase structure. The crystalline structure increases the hardness of coating along with its wear resistance. The friction and wear behavior are assessed by a pin on disc tribometer. Overall, it can be seen that Ni-P/Ni-W-P system performs better compared to Ni-P/Ni-Cu-P in terms of friction and wear. However, heat treatment at higher temperature has negative impact on both the coatings as far as the tribological behavior is concerned. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Symposium on Failure and Preventive Maintenance of Machineries 2022.