Wear-resistant and stable low-friction nanodiamond composite superhard coatings against Al2O3 counter-body in dry condition
Mohamed Ragab Diab, Koki Murasawa, Ahmed Mohamed Mahmoud Ibrahim, Hiroshi Naragino, Tsuyoshi Yoshitake, Mohamed Egiza
Abstract
Conventional machining lubricants pose environmental hazards and increase production costs. This study addresses this challenge by investigating nanodiamond composite (NDC) coatings deposited on WC–Co substrates as a lubricant-free alternative for sustainable machining. The NDC films show superior hardness (65 GPa) compared to the substrate (22 GPa) and enhanced adhesion (HF2). The NDC's unique self-lubrication results in a low and stable friction coefficient (COF ≤ 0.095) and exceptional wear resistance (7.45 × 10 −8 mm 3 /N·m) in dry tesing against Al 2 O 3 counter-body. Compared to CVD diamond, NDC coatings show a 47.8 % reduction in COF and a 31.65 % enhancement in wear resistance, promoting environmentally friendly machining practices. • Eco-friendly CAPD deposits 10 μm thick NDC films on WC−Co at 3.5 μm/h rate. • High-performance NDC films boast 65 GPa hardness and 688 GPa Young's modulus. • NDC films show superior adhesion compared to CVD diamond (HF2 vs. HF6). • NDC maintains stable, low friction (0.095 CoF) against Al 2 O 3 in dry conditions. • NDC films exhibit wear resistance (7.45 × 10^-8 mm 3 /N·m) for harsh environments • NDC coatings reduce COF by 47.8 % and enhance wear resistance by 31.65 % vs diamond.