Atomic-Scale Insights into the Tribochemical Wear of Diamond on Quartz Surfaces
Atomic-Scale Insights into the Tribochemical Wear of Diamond on Quartz Surfaces
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DOI：
10.1016/j.apsusc.2023.158152
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发表时间：
2023-08
影响因子：
6.7
通讯作者：
Jagjeevan S. Bhamra;James P. Ewen;Carlos Ayestarán Latorre;John A. R. Bomidi;Marc W. Bird;D. Dini
中科院分区：
文献类型：
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作者：
Jagjeevan S. Bhamra;James P. Ewen;Carlos Ayestarán Latorre;John A. R. Bomidi;Marc W. Bird;D. Dini
由于金刚石用于高性能切割工具，因此详细了解金刚石磨损至关重要。尽管是一种更硬的材料，但由于摩擦化学机制，金刚石在切割二氧化硅时显示出明显的磨损。在这里，我们使用非平衡分子动力学模拟与反应力场研究单晶金刚石针尖在α-石英表面上滑动的磨损。碳原子的原子间摩擦是通过形成C-O界面键开始的，然后是C-C裂解，扩散到衬底中或进一步氧化形成CO2分子。水分子解离形成羟基，从而钝化表面并减少界面结合和磨损。在低载荷下，初始磨损率随温度和法向应力呈指数增加，与应力增强热激活磨损模型一致。在较高载荷下，初始磨损率对法向应力变得不那么敏感，最终趋于恒定值。这种行为可以用多键磨损模型来描述。在长距离滑动后，磨损也会通过簇经由尾部断裂而脱离而发生。在这里，磨损近似与滑动距离和法向载荷成比例，与Archard模型一致。来自模拟的标准化磨损率在实验测量的范围内。
A detailed understanding of diamond wear is crucial due to its use in high-performance cutting tools. Despite being a much harder material, diamond shows appreciable wear when cutting silicon dioxides due to a tribochemical mechanism. Here, we use nonequilibrium molecular dynamics simulations with a reactive force field to investigate the wear of single-crystal diamond tips sliding on α-quartz surfaces. Atom-by-atom attrition of carbon atoms is initiated by the formation of C-O interfacial bonds, followed by C-C cleavage, and either diffusion into the substrate or further oxidation to form CO2molecules. Water molecules dissociate to form hydroxyl groups, which passivates the surfaces and reduces interfacial bonding and wear. At low loads, the initial wear rate increases exponentially with temperature and normal stress, consistent with stress-augmented thermally activated wear models. At higher loads, the initial wear rate becomes less sensitive to the normal stress, eventually plateauing towards a constant value. This behaviour can be described using the multibond wear model. After long sliding distances, wear also occurs through cluster detachment via tail fracture. Here, wear becomes approximately proportional to the sliding distance and normal load, consistent with the Archard model. The normalised wear rates from the simulations are within the experimentally-measured range.