Surface modification of Al-6061 alloy by copper/graphene green compact electrode in dry electro discharge coating with nitrogen gas as dielectric

Dry Electro Discharge Coating (DEDC) is an emerging, eco-friendly surface enhancement technique that eliminates liquid dielectrics. This study explores its application on Al-6061 alloy using a copper/graphene green compact electrode in a nitrogen environment to improve surface performance. A Taguchi L27 orthogonal array assessed the effects of discharge current, compaction load, pulse-on time (Ton), and electrode composition on coating quality. The highest material deposition rate (MDR) of 0.412 mg/min was achieved with a 5-ton load, 6 A current, 150 µs Ton, and 50:50 Cu:Gr composition. A maximum microhardness of 350 HV was recorded at 15-ton load, 4 A current, 100 µs Ton, and 50:50 compositions. The lowest surface roughness (Ra = 1.825 µm) occurred under 15-ton load, 4 A current, 50 µs Ton, and 50:50 compositions. The highest tool wear rate (TWR) of 2.163 mg/min was observed under high-energy settings. ANOVA identified electrode composition and current as the most significant factors influencing output responses. Grey Relational Analysis (GRA) was used for multi-response optimization, identifying the best parameter settings. A pin-on-disk wear test confirmed enhanced wear resistance of the coated surface compared to the uncoated substrate. Surface characterization using SEM, EDS, and Raman spectroscopy verified the successful deposition of copper and graphene. Overall, DEDC in a nitrogen atmosphere significantly improves the surface integrity of Al-6061 alloy, offering a sustainable and effective solution for developing wear-resistant aluminum components.