Ni基合金喷熔层在NaCl溶液中的抗空蚀性能研究  

Cavitation Erosion Resistance of Ni-based Alloy Sprayed and Fused Coatings in NaCl Solution

作　　者：刘海涛 丁彰雄[1] 黄宝祥 袁成清 LIU Hai-tao;DING Zhang-xiong;HUANG Bao-xiang;YUAN Cheng-qing(Key Laboratory of High Performance Ship Technology(Wuhan University of Technology),Ministry of Education,Wuhan 430063,China)

机构地区：[1]高性能船舶技术教育部重点实验室(武汉理工大学),武汉430063

出　　处：《表面技术》2018年第8期175-181,共7页Surface Technology

基　　金：国家自然科学基金资助项目(51422507)~~

摘　　要：目的比较不同系列Ni基合金喷熔层在NaCl溶液中的抗空蚀性能,并探讨其空蚀机理。方法采用XRD方法分析了氧乙炔火焰喷熔工艺制备的NiCrBSi、WC增强Ni基、NiCrBSiCuMo合金喷熔层的组织结构,采用洛氏硬度计测量了喷熔层的硬度,通过CorrTest电化学测试系统分析了喷熔层在3.5%NaCl溶液中的电化学腐蚀性能,使用超声波振动空蚀仪对喷熔层在NaCl溶液中的抗空蚀性能进行了研究。结果 NiCrBSiCuMo合金喷熔层在NaCl溶液中具有优异的抗腐蚀性能。该喷熔层中除含有Cr_(23)C_6、Cr_7C_3、Cr_3C_2、Cr_2B硬质相外,还存在细化涂层组织、改善涂层韧性的Mo_2C与MoSi_2相,其硬度与NiCrBSi合金喷熔层相近(约58HRC),在3.5%NaCl溶液中空蚀16 h的累积体积损失分别为NiCrBSi和WC增强Ni基合金喷熔层的65%与51%。WC增强Ni基合金喷熔层在含有NiCrBSi喷熔层中Cr的碳化物、硼化物硬质相的基础上,还含有WC与W_2C硬质相,虽然喷熔层具有较高的硬度(59.3HRC),但在NaCl溶液中的腐蚀电位较低,腐蚀电流密度最大,抗空蚀性能较差。结论 NiCrBSiCuMo合金喷熔层在NaCl溶液中具有最优异的抗空蚀性能,WC的加入使Ni基合金喷熔层在NaCl溶液中的抗空蚀性能减弱。The work aims to compare the cavitation erosion resistance of different series of Ni-based alloy sprayed and fused coatings in NaCl solution and explore the coatings’cavitation mechanism.The sprayed and fused coatings of NiCrBSi,WC-reinforced Ni-based and NiCrBSiCuMo alloy were prepared by oxy-acetylene flame spraying and fusing.The structure,hardness and electrochemical corrosion performance of the coatings in 3.5%NaCl solution were analyzed by XRD,Rockwell hardness tester and electrochemical test system(CorrTest),respectively.Furthermore,resistance of cavitation erosion of the coatings in NaCl solution was studied by ultrasonic vibration cavitation equipment.From the results,NiCrBSiCuMo alloy sprayed and fused coating had excellent corrosion resistance in NaCl solution.It contained not only Cr23C6,Cr7C3,Cr3C2 and Cr2B hardness phases,but also Mo2C and MoSi2 phases which could refine structure and improve toughness of the coating.The coating’s hardness was close to NiCrBSi coating(about 58HRC)and its cumulative volume loss was 65%of NiCrBSi and 51%of WC-reinforced Ni-based alloy coating,respectively.The WC-reinforced Ni-based alloy coating also contained Cr carbide and boride hardness phases in NiCrBSi coating besides WC and W2C hardness phases.Although its hardness was pretty high(59.3HRC),it had relatively low corrosion potential,the highest corrosion current density and the worse erosion resistance in NaCl solution.Thus,NiCrBSiCuMo alloy coating has the best cavitation erosion resistance in NaCl solution and the addition of WC weakens the cavitation erosion resistance of Ni-based alloy coating.

关 键 词：氧乙炔火焰喷熔 镍基合金 组织结构 NACL溶液 抗腐蚀性能 空蚀 

分 类 号：TG172[金属学及工艺—金属表面处理]