@article{Tokoroyama2026, 
author = {Takayuki Tokoroyama and Kosuke Suzuki and Asato Tanigawa and Ruixi Zhang and Lulu Li and Noritsugu Umehara and Jongkuk Kim and Jae-Il Kim and Young-Jun Jang and Motoyuki Murashima},
title = {The effect of group 5 metal elements addition to ta-C coating on tribological properties in dry friction},
year = {2026},
journal = {Friction},
volume = {14},
number = {10},
pages = {9441264},
keywords = {5 metal elements, ta-C, friction, Raman, X-ray photoelectron speetroscopy (XPS)},
url = {https://www.sciopen.com/article/10.26599/FRICT.2026.9441264},
doi = {10.26599/FRICT.2026.9441264},
abstract = {Carbon-based hard coatings are ideal for mechanical materials due to their high hardness. However, maintaining low friction in air requires suppressing oxidation by atmospheric oxygen to protect the graphite structure, known for its low friction properties. This study introduced group 5 elements (vanadium, niobium, and tantalum) into the coatings to safeguard the graphite structure and enhance wear resistance through oxidation and reduction reactions. Using a ta-C coating with a high sp3 carbon structure, the effects of these elements were analyzed. The ta-C:Ta coating, containing tantalum, achieved the lowest average friction coefficient of 0.043 in air, followed by ta-C:Nb at 0.067, demonstrating the potential of group 5 elements to improve coating performance.}
}