S111053 境界潤滑性能を支配する吸着膜のナノ物性評価([S111-05]第19回卒業研究コンテスト(5))

Abstract

Additives are components of lubricants. According to the required function, additives have a lot of species. Oiliness additives belong to one of these species. The required function for oiliness additives is the friction reduction under boundary lubrication. It is considered that the friction reduction is derived from adsorption layers which are constructed by the molecules of the oiliness additives. Huge amount of previous papers reported that there is the relationship between the friction reducing effect and the molecular properties. However, the evidence of that relationship was the results from macro-scale friction tests, in spite of that the scales of adsorption layer and molecules are nano-scale or angstrom-scale. Hence, we think that the discussion about the effects of the mechanical properties of adsorption layers on the friction reduction is insufficient. In this study, the relationship between friction behavior in micro-scale and nano tribological properties about the adsorption layers was investigated. Stearic acid and Decanonic acid were used for the oiliness additives. The adsorption of the oiliness additives was measured by Quartz Crystal Microbalance (QCM). Atomic Force Microscope (AFM) was used for observation of the several properties about the adsorption layer and the nano-tribological behavior. And the nano-tribological behavior was compared with the results of the micro scale friction test. From these results, it was observed that the stearic acid constructed the adsorption layer, and the layer of the stearic acid had the friction reducing effect. Finally, correlation of the tribological properties between the micro-scale and nano-scale was found. Similar behavior about friction force was shown in nano- and micro-scale.