Study On The Friction And Wear Performance Of Water Lubricated Rubber And Plastic Bearing Based On Nano-graphite

The comprehensive performance of marine stern bearing materials is an important factor to ensure the safe and stable operation of ships;particularly,the friction and wear properties of tail bearing materials have direct impact on the durability and service life of stern bearing,as well as the safety of the ship.Thus,studying on the friction and wear properties of water lubricated stern bearing and exploring new bearing materials through experiments are of great theory value and practical significance to improve the tribological performance of ship water lubricated stern bearing.The rubber and plastic material which made by adding UHMWPE(Ultra High Molecular Weight Polyethylene)in rubber has been proved to have more excellent lubrication performance.And with the development of nanotechnology,nano rubber bearing materials emerge in endlessly,so it is necessary to study the friction and wear properties of the nano modified water lubricated composite rubber bearing materials.With nano-graphite composite rubber bearing materials as the research object,the friction and wear performances under different load and speed in water lubrication conditions are studied,and the influence of additive amount of nano-graphite on the friction and wear performance is analyzed.And the obtained results are as follows:(1)With water lubrication rubber and plastic bearing material as the matrix,5 kinds of nano-graphite composite rubber and plastic bearing materials and 5 kinds of micron-graphite ones are manufactured by filling in 0,2,4,6,8,10 phr(parts perhundred)of nano-graphite and micron-graphite respectively.And the one with graphite content of 0 is for reference.(2)The experiments of friction coefficients and wear rates of nano-graphite composite rubber and plastic bearing materials,micron-graphite ones,and no graphite ones are carried out on SSB-100 Ship Stern Bearing Test Bed.And the speed characteristics and pressure characteristics were tested and studied contrastively.The results show that,under the same load,the friction coefficients decrease with the increase of relative speed;and in most cases,the friction coefficient of nano-graphite rubber and plastic bearing material is smaller than that of micron graphite one,which shows that the nano-graphite composite rubber bearings is superior to the micron one in speed characteristic;Under the same relative speed,the friction coefficients of both are showed a trend of decline with the increase of pressure,and the pressure characteristic of nano-graphite composite rubber bearings is overall superior than the micron graphite rubber bearing,which shows the nano-graphite composite rubber bearings are better than ordinary micron graphite composite rubber bearings on pressure characteristics;And at the same speed and load,the mass loss of nano-graphite composite is generally lower than that of micron graphite composite.And when the addition amount of nano-graphite is 6 phr,the friction coefficient of the block reaches the minimum;while the minimum mass loss happen with 8 phr nano-graphite.(3)The surface wear out feature and grinding crack of the rubber and plastic blocks are discussed by use of Surface Plasmon Resonance Analyzer and Digital Microscope System.And their wear mechanisms are analyzed.The dispersion and polymerization status of nano-graphite and micron graphite in the rubber and plastic blocks are investigated by using Scanning Electron Microscope.And the causes of friction and wear phenomena in the experiments are explained from the micro level.