Abstract
Powder metallurgy (P/M) electrodes used in electric discharge machining (EDM) often exhibit higher surface roughness (SR) than their solid, ground counterparts, particularly when fabricated from micron-scale powders. This adversely affects friction, wear, and corrosion resistance. These challenges can be addressed by carefully selecting suitable electrode materials. In EDM, key electrode attributes such as material type, composition, and particle size (PS) are crucial in enhancing process performance. In this study, tungsten carbide (WC)/ cobalt (Co) P/M electrodes were developed with PSs varied from the micron to the nano-scale to investigate their effect on EDM performance. The findings indicated that wear and corrosion behaviour were strongly influenced by the PS used to fabricate the tool electrode. Due to their low thermal conductivity and high surface reactivity, nanoparticle-based electrodes promoted greater surface alloying, reduced arcing, and enhanced process stability. The machine tool parameters also altered the size of the surface features such as cavities, globules, and micro-cracks. Consequently, wear and corrosion resistance improved by 77.92% and 84.27%, respectively, due to the formation of carbides and oxides, and microstructural modifications on the machined surface. The results are correlated with the coefficient of friction, SR, hardness, white layer thickness, and microstructural changes, elucidating the mechanisms behind the improved surface characteristics.
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