Synthesis of semi sintered nickel bronze electrode for electric discharge surface alloying of silicon steel and the properties of coated surface

Surface modification of silicon steel was carried out by depositing nickel-bronze (Ni–Cu–Sn) using electrical discharge alloying. Three different compaction pressures (P) (450–650 MPa) were used to prepare compacts of nickel-bronze which were subsequently semi sintered at 1000 °C in a tubular furnace. The surface alloyed using the 450 MPa compacted, semi-sintered nickel-bronze electrode exhibited the presence of pores. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses indicated the uniformity of the nickel-bronze coating on the surface achieved through EDA. The electrode synthesized at the highest compaction pressure of 650 MPa resulted in a uniform nickel-bronze coating on the steel surface. Among the three compaction pressures, the 650 MPa compacted, semi-sintered electrode (Ni–Cu–Sn) demonstrated the best performance in enhancing the hardness of the coated steel substrate, with values of 85.77 HV, 77.28 HV, 96.46 HV, 98.003 HV, and 89.613 HV. Analysis of variance (ANOVA) revealed that compaction pressure (P) is the most significant factor affecting the deposition of nickel-bronze, followed by peak current (I). The tribological behavior of uncoated silicon steel and nickel-bronze-coated steel was analyzed using a pin-on-disc tribometer. The investigation showed that the coated specimens exhibited a lower wear rate (WR) compared to the uncoated specimens. On average, there was a 19% reduction in the specific wear rate (SWR) of Ni–Cu–Sn-coated silicon steel compared to the uncoated specimens. Keywords : Silicon Steel, Microstructure, Electrical Discharge alloying, Powder metallurgy, Tribology.