Effect of hydrophilized PTFE brush structure on seizure resistance in water

Abstract

To prepare exhaustion of oil supplies, alternative lubricant which is good for environment will be required. Water is expected to be a suitable lubricant. However in water lubrication, high wear and seizure come to be problems because of water's low viscosity. Surface texturing is one of the methods reported to overcome these problems. So in this paper, effects of surface brush structure and wettability are investigated expecting improvement of water lubrication property. At first, we conducted thrust cylinder friction test using six kinds of polytetrafluoroethylene(PTFE) specimen; flat, hydrophilized flat, all-brush, hydrophilized all-brush, pattern-brush and hydrophilized pattern-brush. To prepare these specimens, the brush structure was made by irradiating nitrogen ion beam and hydrophilic treatment was conducted by exposing PTFE specimens to plasma generated in the atmosphere of argon and water in vacuum chamber. As results of tests, we found hydrophilized pattern-brush specimen showed good seizure resistance. Then, we prepared hydrophilic pattern specimen which was made by eliminating brush on hydrophilic pattern-brush specimen and conducted friction test to know effectiveness of brush structure inside pattern. As a result, hydrophilic pattern-brush specimen showed better seizure resistance than hydrophilic pattern specimen. So, we concluded that hydrophilic brush structure inside pattern can improve seizure resistance in water lubrication.