Tribological Study On Water Lubricating Bearing Material In Nano Composite UHMWPE

The effect of the ship stern bearing that is support the propeller shaft or shaft.Because of the unpredictable and uneven force field on the ship propeller when sailing,the stern bearing is always in very harsh operating conditions.According to the different method of bearing lubrication,we usually classify it into oil lubricated bearing ship and water lubricated bearing ship.Under the increasingly stringent emission regulations,the researchers of colleges and universities and the Marketing draw more attention on water lubricated bearing because of its simple structure,no pollution.Ultra-high molecular weight polyethylene material（UHMWPE）which is found in the new century as new plastic has very good tribological properties.While as the ship water lubricated stern bearing material it has some defects,it can be offset through material modification.This article main research on tribological properties about the nanocomposite of UHMWPE materials which is modified with ultra-high molecular weight polyethylene as the matrix and nanometer molybdenum disulfide and fluorine rubber as packing.The main research contents contain a set of technologies about how to blend the rubber and plastic for the test preparation of water lubricated stern bearing and including specific operation method and the key to ensure the key influence.Then judge the feasibility of blending process by microstructure observation.Through the bench test to investigate the modified rule about the nanometer molybdenum disulfide and fluorine rubber on UHMWPE and the speed and pressure characteristics、wear and tear characteristics、vibration characteristic of Composite ultra-high molecular weight polyethylene bearings.After a series of process with producing block,bench test,microscopic observation,data analysis and so on.We can conclude that the ultra-high molecular weight polyethylene with white present as the continuous phase and fluorine rubber and nanometer molybdenum disulfide present as discrete phase which is called single phase continuous structure in the nanocomposite UHMWPE water lubricated stern bearing materials in powder state of high temperature and high pressure sintering process.Among them,molybdenum disulfide nanoparticles can maintain the property of nanometer material and parts of them together.Through having tests of nanometer molybdenum disulfide single factor modifying on ultra high molecular weight polyethylene、fluorine rubber single factor modifying on ultra high molecular weight polyethylene and nano molybdenum disulfide combined fluorine rubber modifying on ultra high molecular weight polyethylene on the stern tube bearing test bench,we can find that the coefficient of friction is decrease by the increasing wire speed,the material with single nanometer molybdenum disulfide modifying on ultra high molecular weight polyethylene is not very well to reduce the friction coefficient,the material with single fluorine rubber modifying on ultra high molecular weight polyethylene can reduce the friction coefficient and the lowest at 20%,the material with Molybdenum disulfide and fluorine rubber modifying on ultra high molecular weight polyethylene have the lowest friction coefficient when block as the proportion of molybdenum disulfide and fluorine rubber gradually decline,the nanometer molybdenum disulfide is 8%and fluorine rubber is 16%.Specific pressure characteristic test shows that under the same speed friction coefficient is increasing as load increases,but the friction coefficient is not increasing when the name pressure is from 1.4 MPa to 1.96 MPa.The result of the wear experimental show that the composite have the optimum wear resistance when the nanometer molybdenum disulfide is 8%and fluorine rubber is 16%.When at different rotational speed,the wear type is different.When the rotational speed is very low,the wear morphologies is mainly with abrasive wear due to insufficient lubrication water film,and When the rotational speed is very high,the wear morphologies is mainly with erosive wear.The result of the vibration experimental show that the amplitude is increasing with the increase of rotational speed,and the vertical vibration spectrum are mainly concentrated in0～50 Hz,300～400 Hz and 600 Hz,and the horizontal vibration frequency spectrum are mainly concentrated in 0～200 Hz,300～400 Hz,550～600 Hz.On the whole,the vertical vibration spectrum is lower than the horizontal vibration frequency spectrum.the vertical vibration spectrum and the horizontal vibration frequency spectrum which the MoS₂ is 4%and fluorine rubber is 8%is better than the other block.