摘要
牙轮钻头是钻井设备的重要部件,易受到磨损与腐蚀。为了增加牙轮钻头的工作时效,可在其表面激光熔覆强化层。本研究利用YLS-2000型激光器在牙轮钻头材料15CrNiMo钢表面分别制备了Ni60A熔覆层,以及5%、15%、25%(质量分数,下同)WC增强的Ni基涂层。采用SEM和EDS等方式分析了熔覆层的显微组织及元素分布;利用XRD分析了各Ni60A/WC涂层的物相组成,使用CHI660E型电化学工作站测试了Ni60A/WC涂层的耐腐蚀性能。研究WC含量对Ni60A/WC熔覆层的微观组织与耐腐蚀性能的影响;讨论Ni60A/WC熔覆层与基体在不同pH值腐蚀液中的腐蚀行为。结果表明:随着WC含量的增多,涂层组织出现微区定向凝固;各涂层中均出现了γ(Fe,Ni)以及M23C6、M6C等金属间化合物;相比于基体,在不同pH值腐蚀液中,Ni60A/WC涂层的自腐蚀电流密度降低了1~2个数量级,具备良好的耐腐蚀性能,但其耐腐蚀性与WC的添加量呈负相关;富H+、OH-环境促使钝化膜由低价氧化物转变为高价氧化物。
Roller bit is an important part of drilling equipment which is vulnerable to wear and corrosion.In order to extend the service life of the roller bit,the strengthen layer can be fabricated by laser cladding.In this paper,Ni60 A coating and 5 wt%,15 wt%,25 wt%WC reinforced Ni based coatings were prepared on 15 CrNiMo steel by YLS-2000 laser instrument.Furthermore,the microstructure and element distribution of the coatings were analyzed by means of SEM and EDS.And the phase composition of each coating was investigated by XRD.Meanwhile,the electrochemical corrosion test was performed on a CHI660 E type electrochemical workstation.The effect of WC content on the microstructure and corrosion resis-tance of Ni60 A/WC cladding layer was studied,and the corrosion behavior of Ni60 A/WC cladding layer and substrate in different pH corrosion solution was discussed.The results show that with the increase of WC content,micro area directional solidification appears in the coatings.In addition,theγ(Fe,Ni)and intermetallic compound of M23C6,M6C,et al are observed in Ni60 A/WC layers.What’s more,compared with the substrate,the corrosion current density of Ni60 A/WC coating in different pH value corrosion solution is reduced by 1—2 orders of magnitude which perform good corrosion resistance,but its corrosion resistance is negatively related to the addition of WC.Besides,enrichment of H+and OH-surroundings make the passivation film change from low valent oxide to superoxide.
作者
肖奇
孙文磊
刘金朵
黄海博
XIAO Qi;SUN Wenlei;LIU Jinduo;HUANG Haibo(School of Mechanical Engineering,Xinjiang University,Urumqi 830047,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第8期146-150,共5页
Materials Reports
基金
新疆克拉玛依重大专项(2018ZD002B)。
关键词
激光熔覆
WC
石油钻具
钝化膜
耐腐蚀性能
laser cladding
WC
drilling tools
passive film
corrosion resistance
