Catalytic superlubricity: engineering superlubricity caused by the catalytic effect of gold on hydrogenated amorphous carbon structure

Abstract

<p indent="0mm">Material and energy losses caused by friction and wear hinder the development of mechanical systems. An effective way to solve the problem is to reduce friction coefficient and wear. Here, we proposed <italic>in-situ</italic> formation of graphene nanoribbons <italic>via</italic> gold-catalyzed reconstruction of amorphous hydrogenated carbon matrix to achieve engineering superlubricity. And we called this method “catalytic superlubricity”. In detail, amorphous hydrogenated carbon (a-C:H) films were grown by plasma chemical vapor deposition (PECVD), and gold (Au) films on steel balls were obtained by electroless chemical deposition. Comparing study on the tribology properties of the couple pairs of a-C:H/Au and a-C:H/GCr15 was carried out <italic>via </italic>home-made Tribometer 3. The results show that, compared with the couple pairs of a-C:H/GCr15 (<italic>μ</italic>~0.032 and wear depth of <sc>128 nm</sc> ), the couple pairs of a-C:H/Au show a friction coefficient of 0.008 and wear depth of <sc>40 nm,</sc> respectively. The reason of superlubricity of the couple pairs of a-C:H/Au is that, based on the catalysis of gold, the graphene nanoribbons formed <italic>in-situ</italic> during friction. The ordered structure is conducive to the occurrence of incommensurate contact, and effectively reduces the interfacial shear force and thus lowers the friction coefficient.