Lubrication of Si 3N 4 and Al 2O 3 in water with and without addition of silane coupling agents in the range of 0.05–0.10 mol/l

Abstract

To improve water lubrication of ceramics at a lower sliding velocity, the effect of the addition of silane coupling agents was investigated. Si 3N 4 and Al 2O 3 were slid against themselves in water with and without the addition of silane coupling agents in amounts ranging from 0.05 to 0.10 mol/l. Silane coupling agents containing one or more amino groups were effective in reducing the friction of Si 3N 4 and Al 2O 3 in water. Si 3N 4 also showed significant wear reduction but not Al 2O 3. However, the addition of a silane coupling agent containing an epoxy group increased both friction and wear of Si 3N 4. Improved lubricative characteristics of Si 3N 4 in water and in silane coupling agent solutions were obtained when Si 3N 4 contained smaller amounts of sintering additives. The adsorption behaviour of a silane coupling agent on ceramics was examined using both Fourier transform infrared spectroscopy and thin layer chromatography to clarify the interaction between the silane coupling agent and the ceramics. The role of polysiloxane film formation on ceramics is discussed to demonstrate the lubrication properties of ceramics.