Study On Tribological Properties Of New Water–Lubricated Stern Bearing Material Based On Bionic

Stern bearing is an important supporting component in the ship propulsion systems,its performance directly affects the shipping navigation safety.The lubrication method of traditional stern bearing is often in the oil lubrication,it inevitably appears the leakage of lubrication oil,which polluted the environment of water.With the increasing concerns on the protection of water environmental,the water-lubricated stern bearings is adopted in marine propulsion systems as the future trend.Many developed countries focus on the materials of water-lubricated stern bearing.In this study,the self-lubricated mechanism of lignum vitae were analyzed and the self-lubricated components were extracted.The biomimetic composite materials(guaiacum and high-density polyethylene(HDPE))were designed and prepared based on the principles of bionics.A series of experimental tests were then conducted in the CBZ-1 tribo-tester to investigate the tribological characteristics of the prepared materials.under distilled and saline water respectively.The friction properties of biomimetic materials effected by the sliding speed,applied specific pressure and salt concentration were studied..The coMParison analyses of the friction coefficients,average wear mass losses and the worn surfaces were conducted under different running conditions.The wear mechanism between the pin and the cast copper plate were analyzed using the three-dimensional microscope system,laser interferometer surface profiler and electron scanning microscope.The main results are as following:(1)The self-lubricated mechanism of lignum vitae were analyzed and the related self-lubricated components of lignum vitae were extracted.Four kinds of biomimetic materials(0%,0.5%,1%,3% guaiacum and HDPE)were prepared based on the properties of lignum vitae.(2)In the distilled water condition,the friction coefficient of the rubbing pairs became larger at the beginning of the test,as the extension of test time,the coefficient of friction began to decrease and gradually stabilizes.The friction coefficient and surface roughness of four kinds of material friction pair decreased with the increasing of sliding velocity.Under the same sliding speed condition,the average mass wear rate of the four kinds of material friction pair has no obvious regularity with the change of specific pressure.Analysis of surface wear morphology,the pin sample was presented as a clear height difference with a smooth slope,copper plate surface was full of dense directional furrow traces.(3)In the 3.5% saline water condition,the friction coefficient,the average mass wear rate and the surface roughness of the four kinds of material friction pair decrease with the increase of sliding speed,increase with the increase of the specific pressure.In the condition of low speed and heavy loading,the four friction coefficient of friction and wear rate of the average quality tended to increase as the saline concentration increased.(4)Through the comprehensive analysis,it is clear that the tribological performance of HDPE-G0.5%/ ZCuSn10Zn2 cast copper was the best in the tested materials.The HDPE-G0.5% improves the tribological properties of the rubbing pairs.