超音速喷涂WC-10Co4Cr及WC-12Co涂层的抗海水气蚀性能

Seawater cavitation resistance of supersonic sprayed nano-WC-10Co4Cr and WC-12Co coatings

为提高海洋装备表面抗海水气蚀性能,在45#钢基体上采用超音速火焰喷涂技术(HVOF)分别制备WC-10Co4Cr涂层和WC12-Co涂层。通过扫描电子显微镜(SEM)分析WC-10Co4Cr、WC12-Co粉末和涂层的微观组织结构,并对涂层的孔隙率、显微硬度和电化学性能进行测试表征。将涂层和基体在浓度为3.5%的NaCl溶液中进行抗海水气蚀性能对比实验,探讨涂层的抗海水气蚀机理。结果表明:HVOF制备的WC-10Co4Cr涂层孔隙率为0.42%,显微硬度为1317 HV0.2;WC-12Co涂层孔隙率为0.54%,显微硬度为1253 HV0.2。WC-10Co4Cr涂层的抗腐蚀性能优于WC-12Co涂层;WC-10Co4Cr涂层的抗冲击韧性略优于WC-12Co涂层;在抗海水气蚀性能方面,WC-10Co4Cr涂层优于WC-12Co涂层,而WC-12Co涂层优于45#钢。WC-10Co4Cr涂层与WC-12Co涂层在气蚀冲击力、内应力和海水中Cl−的作用下,导致涂层的微型孔,裂纹不断扩展而出现脱落。

In order to improve the seawater resistance of marine equipment,WC-10Co4Cr coating and WC12-Co coating were prepared on the 45^#steel matrixes using supersonic flame spraying technology(HVOF).The microstructures of WC-10Co4Cr,WC12-Co powders and coatings were analyzed by scanning electron microscope(SEM),and the porosity,microhardness,and electrochemical properties of the coating were tested.The coatings and substrate were subjected to a seawater cavitation resistance comparison experiment under 3.5%NaCl solution.The mechanism of coating seawater cavitation was discussed.The results show that the porosity of WC-10Co4Cr coating prepared by HVOF is 0.42%,the microhardness of the coating is 1317 HV0.2.The porosity of the WC-12Co coating is 0.54%,and the microhardness of the coating is 1253 HV0.2.The corrosion resistance of WC-10Co4Cr coating is better than that of WC-12Co coating.The impact toughness of WC-10Co4Cr coating is slightly better than that of WC-12Co coating.For seawater cavitation resistance,WC-10Co4Cr coating is better than WC-12Co coating,and WC-12Co coating is better than 45^#steel.The micro-holes and cracks of WC-10Co4Cr coating and WC-12Co coating were expanded and fallen off under the action of cavitation impact force,internal stress,and Cl−in seawater.