Static and dynamic contact angles of stock oil and its solutions with additives（fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum） were measured on aluminum surface （Alloy 1145） by ses...Static and dynamic contact angles of stock oil and its solutions with additives（fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum） were measured on aluminum surface （Alloy 1145） by sessile drop technique on an OCA35 dynamic contact angle tester. The effect of additive on the drop spreading was investigated as well. It is shown that the drop spreads very quickly in the first 500 ms after the lubricant contacts with the aluminum surface, and then does slowly later. The dynamic contact angle decreases exponentially with time. In contrast to the stock oil, although addition of polarity additive of long chain alkyl into stock oil is able to decrease the surface tension of solutions, it weakens the wetting dynamic, which results fi＇om the adsorption at the expanding solid/liquid interface. Among the same long chain polarity organic compounds used, dynamic wetting decreases in the order of fatty acid, fatty alcohol and fatty ester. The blend of fatty alcohol and fatty methyl ester can improve the oil wetting dynamics and promote the lubricant spreading.展开更多
Oil-in-water （O/W） emulsions are widely used in metal working such as hot rolling and cutting. Three kinds of O/W emulsions with low oil concentration were prepared which include conventional emulsion （CE）, miniem...Oil-in-water （O/W） emulsions are widely used in metal working such as hot rolling and cutting. Three kinds of O/W emulsions with low oil concentration were prepared which include conventional emulsion （CE）, miniemulsion （MNE） and microemulsion （ME）. The lubricating properties of O/W emulsions with low oil concentration were investigated using the tribological testers and the thin film interferometry based on the relative optical interference intensity method. The tribological test results under boundary lubrication show that the friction coefficient and the total losing weight can be clearly seen： CE 〈 MNE 〈 ME. The lubricating film thicknesses under elastohydrodynarnic lubrication and thin film lubrication show that a relationship of the film formation abilities： CE 〉 MNE 〉 ME. Competitive wetting behavior of water and oil on solid surface was confirmed to play an important role in the film formation and tribological behaviors of O/W emulsion.展开更多
基金Project (01C26224300195) supported by the National Innovation Fund for Technology Based Firms
文摘Static and dynamic contact angles of stock oil and its solutions with additives（fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum） were measured on aluminum surface （Alloy 1145） by sessile drop technique on an OCA35 dynamic contact angle tester. The effect of additive on the drop spreading was investigated as well. It is shown that the drop spreads very quickly in the first 500 ms after the lubricant contacts with the aluminum surface, and then does slowly later. The dynamic contact angle decreases exponentially with time. In contrast to the stock oil, although addition of polarity additive of long chain alkyl into stock oil is able to decrease the surface tension of solutions, it weakens the wetting dynamic, which results fi＇om the adsorption at the expanding solid/liquid interface. Among the same long chain polarity organic compounds used, dynamic wetting decreases in the order of fatty acid, fatty alcohol and fatty ester. The blend of fatty alcohol and fatty methyl ester can improve the oil wetting dynamics and promote the lubricant spreading.
基金supported by the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20100007120010)the Tribology Science Fund of State Key Laboratory of Tribology (Grant No. SKLTKF11A05)Science Foundation of China University of Petroleum,Beijing (GrantNo. KYJJ2012-04-17)
文摘Oil-in-water （O/W） emulsions are widely used in metal working such as hot rolling and cutting. Three kinds of O/W emulsions with low oil concentration were prepared which include conventional emulsion （CE）, miniemulsion （MNE） and microemulsion （ME）. The lubricating properties of O/W emulsions with low oil concentration were investigated using the tribological testers and the thin film interferometry based on the relative optical interference intensity method. The tribological test results under boundary lubrication show that the friction coefficient and the total losing weight can be clearly seen： CE 〈 MNE 〈 ME. The lubricating film thicknesses under elastohydrodynarnic lubrication and thin film lubrication show that a relationship of the film formation abilities： CE 〉 MNE 〉 ME. Competitive wetting behavior of water and oil on solid surface was confirmed to play an important role in the film formation and tribological behaviors of O/W emulsion.
