液晶润滑添加剂的减摩作用机理研究

Research on the Antifriction Mechanism of Liquid Crystal Additives

液晶润滑添加剂具有优良的减摩性能，但在已有的文献报道中涉及其减摩机理的研究内容却还很少，因此，利用向列型液晶材料己氧基苯甲酸和正辛基苯甲酸作为ＨＵ－２０汽轮机油的添加剂，在给定的压力、速度和温度条件下于Ｆａｌｅｘ试验机上进行了液晶的减摩性能试验研究，并且用Ｘ射线衍射、俄歇电子能谱和扫描电子显微镜等技术，对溶解于矿物抽中的液晶结构、磨损表层的元素组成及其表面形貌作了观察、分析与研究，在此基础上又对液晶的减摩作用机理进行了分析与探讨。结果表明，溶解于油中的液晶是以晶体微粒形式弥散于油中；在摩擦过程中，液晶分子以其极性基团羧基－ＣＯＯＨ在摩擦副表面定向排列吸附形成减摩保护层，氧化反应层的形成和表层氧化铁的组成变化对液晶的减摩作用都有重要影响；液晶微粒填充摩擦副表面细小凹坑使表面变得光滑平整易于滑动，这也是其具有良好减摩性能的重要原因。

Liquid crystal additives(LCA ) have good antifriction property. But in previousreports,the contents which involved the research on the antifriction mechanism of LCA is very little. Here an experiment has been taken on a Falex tester under the given conditions of pressure,velocity and temperature to study the antifriction property of LCA. In the experiment,some nematic phase liqulti crystal,for example,4-hesoxy benzoic acid and n- 4-octyl benzoic acid have been selected as the additives to the HU-20 turbine oil,and the structure of liquid crystal dissolved in mineral oil and the morphology and element composition of wearing surface have been observed with the aid of X-ray diffraction,Auger electron spectroscopy and scanning electron microscopy. On the basis of what has already been achieved,the antifriction mechanism of LCA has been further analvzed.The results show that the LCA is dispersed in the oil in the form of fine crystal grains.During the rubbing procesess,the molecules of liquid crystal are adsorbed and arranged directionally on the surfaces of friction pair through their polar group-carboxy(-COOH),and form an antifrictional protectine layer. The formation of oxide film and the composition change of the ferrous oxide in surface laye rs significantly influence the antifriction effect of LCA. The LCA grains can fill in the micro concaviticS on the surfaces of friction pair,making them smcother and sliding easier.This is another important reason of the antifriction effect of LCA.