Chemical Basis of the Tribological Properties of AgTaO3 Crystal Surfaces

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• 作者：Hongyu Gao ; Alberto Otero-de-la-Roza ; Samir M. Aouadi ; Ashlie Martini ; Erin R. Johnson
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 7, 2014
• 年：2014
• 卷：118
• 期：31
• 页码：17577-17584
• 全文大小：612K
• ISSN：1932-7455

文摘

The chemical properties of a surface determine the friction and wear behavior of a material during sliding. In this article, we study the mechanisms underlying the sliding behavior of the AgTaO₃ perovskite material, a promising high-temperature solid lubricant that presents excellent friction properties and is chemically inert. In particular, by employing a combination of molecular dynamics simulations and density-functional theory calculations, we show that the low friction of AgTaO₃ at high temperature is explained by silver aggregation on the surface, which is enabled by the low energy barriers associated with silver migration. Two different surface terminations (AgO and TaO₂) are studied, and we show that the migration barrier on the AgO surface is smaller, favoring silver aggregation, which affects both friction and wear. Regardless of the termination, the formation of soft silver clusters dominates the sliding behavior when enough energy (mechanical or thermal) is imparted to the surface.