Investigation of the running-in process and friction coefficient under the lubrication of ionic liquid/water mixture

• Published in: Applied surface science Vol. 255; no. 12; pp. 6408 - 6414
• Main Authors: Xie, Guoxin, Liu, Shuhai, Guo, Dan, Wang, Quan, Luo, Jianbin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2009; Elsevier
• Subjects: Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; Interface structure and roughness; Ionic liquid/water; Liquid crystals; Orientational order of liquid crystals; electric and magnetic field effects on order; Physics; Running-in process; Solid surfaces and solid-solid interfaces; Structure of solids and liquids; crystallography; Surface physical chemistry; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin films; Water-based lubrication; 61.30.Hn; Thin films; 68.35.Ct; 68.05.Gh; Water-based lubrication; Ionic liquid/water; 47.85.mf; Running-in process; Water; Liquid state; Silicon nitride; Hydrodynamics; Inorganic compound; Thin film; Ionic liquid; Silicon oxides; Wear; Friction coefficient; Lubrication
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2009.02.029

The tribological properties of three different films commonly used in microelectromechanical systems (MEMS) under the lubrication of ionic liquid (IL)/water mixtures with various concentrations in the running-in process have been investigated. Results show that coefficients of friction (COFs) and wear rates for low temperature silicon oxide (LTO)/Si 3N 4 vary in a similar way to the ones for poly-Si/Si 3N 4 under the lubrications of different IL/water mixtures. In contrast, the differences in COFs and wear rates are more significant in that the COFs and wear rates increase dramatically with the decrease in IL/water concentration in the case of self-mated Si 3N 4, while the differences in COFs and wear rates for the two other tribopairs are relatively small when the concentration is changed. The period of the running-in process reduces with the increase in IL/water concentration for all the tribopairs. Effective hydrodynamic lubrication can be found in the case of Si 3N 4/Si 3N 4 tribopair at higher IL/water concentrations without an evident running-in process, however, such a phenomenon cannot be observed for the other two tribopairs. Different wear mechanisms will also be analyzed in this paper.