摘要
利用金相显微镜、扫描电镜和X射线衍射仪等,分析了超音速火焰喷涂WC-CoCr和WC-Ni金属陶瓷涂层的物相组成和显微结构。通过电化学工作站测试了涂层在3.5%(质量分数)NaCl溶液中的动电位极化曲线和奈奎斯特阻抗谱,并与镀铬层进行了对比。结果表明:该涂层由WC硬质相和金属黏结相组成,组织均匀致密无分层,孔隙率低于1.5%;在NaCl溶液中的耐腐蚀性能从高到低依次为WC-CoCr涂层、WC-Ni涂层、镀铬层;超音速喷涂涂层组织致密,Cl-难以穿透涂层,因此其耐腐蚀性能较高;添加少量的铬可以促使CoCr合金黏结相表面形成钝态膜,因而WC-CoCr涂层的耐腐蚀性能优于WC-Ni涂层的。
The phase composition and microstructure of high velocity oxygen fuel（HVOF）sprayed WC-CoCr and WC-Ni cermet coatings were analyzed by metallographic microscope,scanning electron microscope,X-ray diffractometer and so on.The potentiodynamic polarization curves and the Nyquist impedance spectra of the coatings in 3.5%（mass fraction）NaCl solution were measured by electrochemical workstation and compared with those of the chromium layer.The results show that：the coatings consisted of WC hard phase and metal binder phase,with a homogeneous and dense microstructure and porosity less than 1.5%;in NaCl solution,the corrosion resistance from high to low was that of WC-CoCr coating,WC-Ni coating,chromium layer;the structure of the HVOF coatings was dense,which prevented the coatings from Cl^-,thus the corrosion resistance of the coatings was better;the addition of a little chrome promoted the formation of a passive film on the surface of CoCr binder phase,thus the corrosion resistance of WC-CoCr coating was better than that of WC-Ni coating.
出处
《理化检验（物理分册）》
CAS
2017年第3期151-156,160,共7页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
基金
江苏省自然科学基金资助项目(BK20150806)
中国科学院核用材料与安全评价重点实验室开放基金资助项目(2016NMSAKF03)
材料腐蚀与防护四川省重点实验室开放基金资助项目(2016CL08)
关键词
超音速火焰喷涂
金属陶瓷涂层
显微结构
耐腐蚀性能
high velocity oxygen fuel spray
metal ceramic coating
microstructure
corrosion resistance
