2023-06-07 オークリッジ国立研究所(ORNL)
◆スライディングパーツに超潤滑性をもたらす炭素ナノチューブからなるコーティングについての研究を行い、Materials Today Nanoに発表しました。
◆このコーティングは、鋼同士の摩擦を100倍以上減少させ、年間約1兆ドルの摩擦と摩耗による経済損失を減少させることができます。この革新的な技術は、エネルギー効率を向上させるための有望な手段となります。
＜関連情報＞
- https://www.ornl.gov/news/superlubricity-coating-could-reduce-economic-losses-friction-wear
- https://www.sciencedirect.com/science/article/abs/pii/S2588842022001250
犠牲的なカーボンナノチューブコーティングによるマクロスケールの超潤滑性 Macroscale superlubricity by a sacrificial carbon nanotube coating
Chanaka Kumara, Michael J. Lance, Jun Qu
Materials Today Nano Available online: 16 December 2022
DOI:https://doi.org/10.1016/j.mtnano.2022.100297
Abstract
Superlubricity, i.e., coefficient of friction (COF) below 0.01, was earlier limited to microscale in controlled environments in the earlier literature and more recently realized for macroscale sliding of ceramic or carbon surfaces lubricated by water or other polar fluids. However, there is lack of report of superlubricity for the most common bearing system, i.e., steel-steel contact in non-polar oil lubrication. Here we present ultra-low COF of 0.001–0.007 by using a sacrificial coating composed of vertically-aligned carbon nanotubes (CNTs) for macroscale steel-steel sliding under minimum quantity lubrication (MQL) of a polyalphaolefin (PAO) oil in the ambient environment. Raman spectroscopy and electron microscopy analyses detected graphene-containing tribofilms on both the steel surfaces, which was produced by the fractured CNT flakes and metallic wear debris during running-in. The in situ formed graphene-graphene contact interface presumably possesses a low shear resistance leading to superlubricity. The presence of oil, despite as little as one droplet, has proven to be crucial. Such a superlubricity performance has shown good sustainability in extended testing of more than 500,000 cycles and strong ability of accommodating changes in sliding conditions. Results here demonstrate feasibility with fundamental insights for achieving ambient environment macroscale superlubricity.
