Thermo-Chemical Wear Mechanism of Ultrafine Diamond Cutting Edge

切割边缘的耐久性是超精确切割工具的一个常见要求。因为在与工作材料接触的敏感性下切割边缘是不可避免地被提升温度的问题，热化学过程被认为是一种穿着钻石切割工具的基本机制。为了理解切割边缘的磨损特征，简化的实验模拟了热化学过程，从而产生了结果。在另一个方面，以热力学和量子化学为基础，在结合能的条件下分析了碳原子表面的行为。“实验的结果和分析显示了热机制--钻石的化学穿戴过程就像遵循一样。”氧化物原子在金刚石表面上的吸收，以确定碳原子在金刚石晶体第一层上的稳定结构或结合。当一种特定的金属原子存在于被吸收的氧原子之间，使金属和氧原子之间的相互作用得到增强。当温度上升到金属接触的氧化水平时，特定表面上的碳原子被移走为碳氧化物的形式。因此，大气层的温度和氧的局部压力是一个重要因素，可以确定钻石的热化学磨损过程。It is difficult to prevent the wear of cutting edge due to the restriction in realistic condition of atmosphere attainable。However，热化学过程的应用对金刚石的高效率治理是可行的。

Durability of cutting edge is a common requirement for ultra-precision cutting tool. Because the cutting edge under attritious contact with workmaterial is inevitably subject to elevated temperature, thermo-chemical process is considered to be an essential mechanism on wear of diamond cutting tool. To understand the wear characteristics of cutting edge, the simplified experiments simulating the thermo-chemical process are carried out. On the other hand, based on the thermodynamics and quantum chemistry, the behavior of carbon atom on the surface of diamond specimen is analyzed in terms of binding energy. The results of the experiments and the analysis show that the mechanism of thermoーchemical wear process of diamond is as follows. The adsorption of oxygen atom on diamond surface deteriorate the stable structure or binding of carbon atom on the first layer of diamond crystal. The deterioration is enhanced when a specific metal atom exists near the adsorped oxygen atom due to the interaction between the metal and the oxygen atoms. When the temperature is elevated to the oxidization level of contacting metal, the carbon atoms on the specimen surface are removed as the form of carbon oxide. Therefore, the temperature and oxygen partial pressure of atmosphere are the important factors determining the thermo-chemical wear process of diamond. It is difficult to prevent the wear of cutting edge due to the restriction in realistic condition of atmosphere attainable. However, the application of thermo-chemical process to the high efficiency polishing of diamond can be feasible.