Parametric Effect on Tribological Performance of Plasma-Sprayed Composite Coating on Bearing Steel

The optimization of pin-on-disc (POD) input parameters that influence the tribological properties of uncoated bearing steel EN31 and atmospheric plasma-sprayed (APS) NiAl + Al 2 O 3 + CeO 2 composite-coated bearing steel EN31 is discussed in this paper. A 70 + 10 + 20 mixture of nickel aluminium (NiAl), aluminium oxide (Al 2 O 3 ) and cerium oxide (CeO 2 ) is coated on EN31 using APS. Wear tests on uncoated and coated specimens were performed under lubrication conditions using pin-on-disc tribometer in the current study. The Taguchi L25 approach was used to vary three input process parameters: load, rotational speed and temperature. The coefficient of friction (COF) and specific wear rate values of uncoated and coated EN31 are evaluated. Statistical analysis on experimental data shows that temperature (40.76%) and rotation speed (39.74%) show high level of contribution on COF for uncoated EN31 whereas temperature (40.58%) and load (35.14%) show high level of contribution on COF for coated EN31. Similarly, temperature (79.15%) shows high level of contribution on specific wear rate for uncoated EN31 whereas rotation speed (43.12%) and temperature (35.77%) show high level of contribution on specific wear rate for coated EN31. Worn surfaces of uncoated and coated samples after POD test were examined through scanning electron microscopy.