Abstract:Poor lubrication between the ship's propeller shaft and the bearing causes serious wear and abnormal noise, which brings danger to its reliability and stealth. In this paper, polytetrafluoroethylene (PTFE) and polyoxymethylene (POM) plastics with different surface wettability were selected to conduct ring-block friction test under six working conditions in water environment to analyze their tribological characteristics. The vibration signal was collected by the friction test device with the high- precision vibration acceleration sensor, and the signal characteristics were enhanced by wavelet packet decomposition and reorganization. The molecular structure of the friction surface of the materials before and after the test was characterized by Raman spectrum. The results show that the specific wear rate of PTFE under high load changes linearly with the increase of speed, while POM shows a significant exponential change. There is no chemical change on the surface of the materials after friction, and the copper rings are not scratched and transferred to the surface of the materials. Compared with PTFE, the frictioninduced vibration of POM is more severe at low speed and slighter at high speed. When the speed reaches 1000 r/min, the stable water film exists on the surface of POM, which shows good water lubrication.