Surface characterization of the diamond polishing pads and their performance evaluation in nanofinishing of electroless nickel plating

In this work, the cost-effective precision finishing of electroless nickel plating using a compliant tool is presented. The shape adaptive grinding (SAG) process with diamond abrasive polishing pad is used for finishing of a plated surface on a stainless-steel substrate. The variable parameters in the SAG are tool compression, rotational speed of the tool, and particle size of diamond abrasive pads (9, 15, and 30 mu m). Forces acting on the workpiece and areal surface roughness are the output parameters. Diamond abrasive pads are characterized for particle distribution and topography. Detailed topographical analysis of abrasive pads provides a better understanding of the change in surface characteristics and material removal mechanism with the different abrasive sizes. It is observed that fine diamond abrasive pads generate low surface roughness, while medium and coarse pads have higher wear resistance. The final finishing is performed at the optimal process parameters, and the final areal surface roughness of 7 nm is achieved. The topography, morphology, and wettability of the surface after finishing are analysed to correlate the effect of operating conditions. The article also highlights the pad loading and abrasive wear that significantly affect the outcome of the polishing process.