A Study on Tribodegradation of Lubricating Oils under Rolling friction and Friction-polymer formation

作为研究的第一步，研究了实验方法和程序。本研究的主要目的是寻找一种在摩擦试验中只使用少量试验液而不造成严重损伤的试验方法，并检测降解油中所含的少量化合物。选用滚动四球摩擦磨损试验机作为摩擦试验装置，采用傅立叶变换红外光谱（FT-IR）和高效液相色谱-凝胶渗透色谱（HPLC-GPC）对降解油进行分析，试验条件为：轴向载荷294 N和98 N，转速2500 rpm，温度室温。使用高度纯化的加氢精制的石蜡矿物油作为试验油。在294 N下的摩擦实验之后，油变得油腻，并且样品油的颜色变为褐色。红外光谱（FT-IR）分析表明，降解油中存在>C=O、-OH、-COO^-、Fe_2O_3等杂质，凝胶渗透色谱（GPC）分析表明，即使用孔径为0.45 μ m的膜过滤器过滤，降解油中仍有大量杂质存在。证实在油的静态氧化中没有形成如此大尺寸的物质。可以得出结论，在降解的油中含有非常细的磨损颗粒，其表面上吸附有具有>C=O，-COO-基团的氧化产物。这使得降解的油变得油腻。在98 N下，油不发生油脂化和褐变，但含有-COO^-和Fe_2O_3等特征基团。

Experimental methods and procedures were studied as a first step of the research. The major objectives of the study were to find the experimental method which anable to use only a small amout of test fluids without sever damages during friction tests and to detect the small amout of compounds which were contained in the degraded oils. Rolling-four-ball tribometer was selected as friction apparatus and FT-IR and HPLC-GPC were selected for the analyzes of the degraded oils.The experimental condition of friction experiments were ; axial load : 294N and 98N,rotating speed : 2500rpm, temperature : room temp. Highly purified hydrorefined paraffinic mineral oil was used as the test oil. After the friction experiment under 294N,the oil became greasy and color of the sample oil changed to brownish. Presence of >C=O,-OH,-COO^-, Fe_2O_3 were found in the degraded oil by FT-IR.From the GPC,very large substance was detected in the degraded oil, in spite of the filtration with memblane filter having a pore size of 0.45mum. It was confirmed that such a large size substance was not formed in the static oxydation of the oil. It can be concluded that very fine wear particles on the surface of which oxydation products having >C=O,-COO- groups were adsorbed, were contained in the degraded oil. This made the degraded oil greasy. Under the 98N,the oil did not change to greasy and brownish but some characteristic chemical groups like -COO^- and Fe_2O_3 were also found in the oil.