高温で速度に影響されない「理想の摩擦」を呈する挙動を観測 — 摩擦の起源解明につながる新発見 —

2026-07-23 物質・材料研究機構

＜関連情報＞

• https://www.nims.go.jp/press/2026/07/202607230.html
• https://journals.aps.org/prl/abstract/10.1103/y3jy-nqcd

雲母上の速度に依存しない乾燥摩擦：理想的なアモントン・クーロン摩擦の実現 Velocity-Independent Dry Friction on Mica: Realization of Ideal Amontons-Coulomb Friction

Hiroshi Sakuma, Diane E. Moore, David A. Lockner, and Toshihiro Kogure
Physical Review Letters  Published: 20 July, 2026
DOI: https://doi.org/10.1103/y3jy-nqcd

Abstract

The Amontons-Coulomb friction law assumes that the frictional force between materials is independent of sliding velocity. However, as Coulomb noted, this is a rough approximation, and a second-order dependence of friction on the logarithm of sliding velocity is incorporated in a commonly used “rate- and state-dependent” friction representation. Here, we conduct shear experiments on mica, a layer-structured mineral, at temperatures ranging from 22 to 2⁢0⁢0 °C and under normal stress of 100 MPa. The friction coefficient clearly depends on the logarithmic sliding velocity at 2⁢2 °C, but rate sensitivity decreases with increasing temperature until at 2⁢0⁢0 °C, the friction coefficient is independent of sliding velocity. Our findings could initiate the development of velocity-independent frictional materials, realizing the ideal Amontons-Coulomb friction.