| Wear failure is the primary reason causing the failure of rubber components used in industrial equipment.As an extremely complex phenomenon,the abrasion of materials is restricted by many factors,such as the material's characteristics,the environment and the tribological system.Research on the friction and wear behavior of rubber materials has always been the focus in the field of tribology,however,the researches on the rubber's erosion behavior are limited and immethodical.Especially,there are few reports about the influence of environmental factors on the erosion resistance of rubber materials.In this dissertation,nitrilebutadiene rubber(NBR)was selected as the experimental material.The swelling and erosion behaviors of NBR in the simulated marine environment were investigated,the erosion characteristics was analysed and the erosion mechanism was revealed.On this basis,the formulation was modified to promote the NBR's swelling and erosion resistance in sea water.The basic formulation of NBR was presented,three kinds of NBR specimens with different acrylonitrile contents(18 wt%,26 wt% and 41 wt%)were manufactured,and their intrinsic properties were characterized.In order to simulate the marine environment more practically,a slurry erosion tester for rubber materials has been designed and manufactured,which can meet the test conditions,and has the characteristics of controllable impact velocity,adjustable impact angle,optional nozzle shape and variable slurry concentration.Before test,the accuracy of the tester was verified by repeatability experiment.In order to better elucidate the effect of seawater on the properties of NBR,deionized water was selected as the reference material.The swelling behavior of the three NBR specimens in deionized aqueous solution and their erosion behavior under the impact of aqueous slurry were studied experimentally,the swelling and erosion mechanism were analyzed.This part was taken as the standard experiment,and the results were compared with those obtained in sodium chloride solution,so that the effect of seawater on the erosion resistance of NBR could be explained more intuitively.The sodium chloride solution with molar concentration of 3.5% was used to simulated the seawater,the quartz sand was selected as the impact particles,the static swelling experiment and erosion test at ambient temperature and pressure were performed.The results showed that sodium chloride solution has certain influence on the physical properties,surface composition,swelling resistance and erosion resistance of NBR specimens.The diffusion behavior of chloride and sodium ions of sodium chloride solution in NBR was analyzed,the mechanism of sodium chloride solution affecting the swelling and erosion resistance of NBR was described and the interaction between swelling and erosion was discussed.According to the working conditions,the impact test of nitrile-butadiene rubber specimens was carried out under the conditions of sodium chloride slurry with different particle sizes(20,28,35,48,65,80 and 100 mesh)and different impact angles(5°,30°,45°,60°,75 and 90°).The influence of particle size and impact angle on the erosion wear characteristics of NBR specimens were studied.The results show that the size of impact particle and the impact angle of slurry have different effects on the erosion rate and the surface abrasion morphologies of NBR specimens and also effect the particle trajectory.Also,the reasons for this phenomenon were analyzed and its mechanism was described.In order to improve the swelling and erosion resistance of NBR in marine environment,the formulation of NBR was improved based on the above experimental researches and analyses.Nano-zinc oxide was selected to replace the original vulcanizing activator,silane coupling agent KH550 was chosen to modify the NBR's surface.The NBR's physical properties,mechanical properties,vulcanization characteristics,swelling and erosion resistance in sodium chloride solution were studied.It was found that the intrinsic properties,erosion and swelling resistance of NBR were improved to a certain extent by adding nano-zinc oxide.Finally,the mechanism of its performance improvement was expounded. |
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