| The service reliability and operation performance of deep-sea drilling equipment determine its drilling capability.Under actual conditions,the key components such as drill pipe in deep-sea drilling equipment are easily affected by a variety of factors.WC-CoCr cermet coating prepared by HVOF technology can effectively improve the wear resistance,erosion resistance and cavitation performance of equipment parts due to its high hardness and excellent wear and corrosion resistance.And then improve their working life and ensure the safety of service.In this paper,two kinds of WC-10Co4 Cr coatings(conventional structure and bimodal structure)were prepared on 35 CrMo steel substrate by HVOF,and a series of characterizations were carried out to explore the differences of the erosion,cavitation and friction properties of the two kinds of coatings under simulated conditions were investigated.The failure mechanism of the two kinds of coatings under different parameters and the difference of corrosion resistance and wear resistance were also investigated.(1)The erosion resistance of conventional and bimodal coatings prepared by High Velocity Oxygen Fuel technology(HVOF)was investigated by using the MLD-10 erosion tester.Configuration of simulated seawater(3.5 wt.% NaCl solution)as erosion medium,the erosion resistance of the two coatings under different erosion concentration,erosion particle size and pH parameters was investigated,and the failure mechanism was discussed according to the microstructure of erosion zone.(2)Based on the ultrasonic vibration cavitation erosion tester,the cavitation corrosion resistance of the coating in simulated seawater was investigated.By measuring the volume loss at the same cavitation time,the difference of cavitation corrosion resistance between conventional and bimodal structural coatings was compared and analyzed.Considering the influence of corrosion medium in simulated seawater on the coating,the cavitation corrosion failure mechanism of the two kinds of structural coatings was investigated.(3)The wear properties of conventional and bimodal coatings were studied by UMT-5 friction and wear tester,and the difference of dry friction properties between the two coatings under different experimental loads was discussed.Based on the friction coefficient,three-dimensional morphology of wear mark and micro-morphology of wear mark under different parameters,the relationship between dry friction properties and load of conventional and bimodal structure coatings was investigated,and the failure mechanism was discussed. |
PDF Full Text Request