The cavitation-erosion rules and synergistic mechanism of the AC-HVAF sprayed Fe-based amorphous metallic and WC-10Co-4Cr metallic cermet coatings in hydraulic fracturing fluid were studied by means of the ultrasonic cavitation and electrochemical testing methods.The leading role of the corrosion resistance and hardness during the cavitation was determined.The results showed that the existing of KCl in the fracturing fluid had a significant impact on the cavitation behavior of the coatings,especially for the lower corrosion resistance of metallic cermet coating.The cavitation performance of coatings in fracturing fluid was a double variable function of corrosion resistance and hardness.Mechanical damage of cavitation had a significant effect on cavitation erosion process of high hardness coating.The cavitation-erosion resistance of coatings was mainly dependent to hardness,and the high hardness of WC metallic cermet coating exhibited excellent cavitation-erosion resistance.The cavitation-erosion damage of coatings originated from the pores and defect areas,the hard phases striped off the surface and thus led to the damage of the hard metals and coa-tings.Reducing porosity and improving bonding strength were helpful to improve the corrosion resistance of coatings in fracturing fluid.%采用超声空蚀与电化学测试相结合的方法,对AC-HVAF热喷涂非晶金属和金属陶瓷两种涂层在水力压裂液中的空蚀及交互作用规律进行了研究,分析了耐蚀性和硬度在空蚀时的主导作用,确定了空蚀机理.结果表明,压裂液中KCl恶化了涂层的腐蚀性能,进而影响了空蚀行为.涂层在压裂液中的抗空蚀性能是耐蚀性与硬度结合的双变量函数.空化的力学破坏对高硬度涂层的空蚀过程有显著影响,硬度相对较高的金属陶瓷防护涂层的抗空蚀性能优异.压裂工况下,AC-HVAF涂层空蚀损伤是由于气泡溃灭垂直冲击孔隙或缺陷区域,硬相直接被剥离表面.降低孔隙和提高粘结相结合强度有助于提高涂层在压裂液中的抗空蚀性能.
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