Influence of droplet-free ta-C coatings and lubrication conditions on tribological performance and mechanical characteristics of WC−Co

• Published in: Materials letters 2024-10, Vol.372, p.137058, Article 137058
• Main Authors: Murasawa, Koki, Diab, Mohamed Ragab, Wang, Mei, Naragino, Hiroshi, Yoshitake, Tsuyoshi, Egiza, Mohamed
• Format: Article
• Language: English
• Subjects: Arc ion plating; ta-C coatings; Tribological performance; WC−Co substrates; Wear resistance
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2024.137058

•Arc ion plating deposited droplet-free ta-C coatings with high adhesion (Lcr = 41 N).•The hardness of ta-C coatings is 62 % higher than that of WC−Co, reaching 60 GPa.•ta-C coatings reduce the COF (0.123) in dry conditions by 23 % compared to WC−Co.•ta-C coatings achieve a 42 % decrease in friction (CoF=0.092) with water-soluble lubricants compared to dry conditions.•ta-C coatings significantly enhance wear resistance across various lubrication conditions. Cemented carbide (WC−Co) tools suffer from surface abrasion, limiting their performance. This study explores droplet-free tetrahedral amorphous carbon (ta-C) coatings deposited via arc ion plating as a solution. The coatings possess a dense, sp3-rich structure, leading to a remarkable hardness of 60 GPa compared to 37 GPa of WC−Co, and strong adhesion with a critical scratch load of 41 N. Tribological tests confirm their effectiveness. Dry sliding tests show reduced wear and lower CoF (0.123) compared to uncoated tools (0.159). Notably, water-soluble lubricants yielded the best performance (lowest CoF: 0.092, superior wear resistance), while water and mineral oil also improved performance.