超音速电弧喷涂NiTi混合涂层及其组织结构表征研究

Supersonic Arc Spraying Coating NiTi Composite Structure and Tissue Characterization

目的为改善NiTi涂层在工程应用中的不足,研究一种性能更优越的表面喷涂材料。方法先对0Cr13Ni5Mo不锈钢基体表面进行预处理,包括用丙酮清洗(除油、除锈)及喷砂处理(棕刚玉颗粒),选择超音速火焰喷涂技术在基体表面分别制备NiTi/Ni、NiTi和NiTi/NiAl三种混合涂层,并分别采用扫描电镜(SEM)和X射线衍射仪(XRD)对三种混合涂层的显微组织结构和形貌及相组成进行表征,同时在显微硬度计上进行硬度试验,测量三种涂层的厚度和硬度,并观察涂层与基体的结合界面形貌,进而对上述三种涂层的组织结构表征进行对比研究。结果 NiTi/Ni、NiTi、NiTi/NiAl涂层的硬度平均值分别为574.3、683.3、735,NiTi/Ni、NiTi、NiTi/NiAl涂层试样的平均厚度分别为279.3、270.5、229.4μm。NiTi/Ni混合涂层的主要组织为Ni3Ti和Ni,NiTi涂层的主要成分为NiTi(B2)相、NiO、TiO以及少量的NiO_2,NiTi/NiAl涂层主要含有NiTi、NiAl及少量的单质Ni和NiO_2。结论 NiTi/NiAl混合涂层的硬度最高,与基体的结合界面最致密,具有极强的抗氧化性,组织较均匀,因此总的来说,NiTi/NiAl混合涂层的性能稳定,工程应用中有望成为更加理想的涂层材料。

Objective To improve deficiencies of NiTi coating in engineering applications and find a superior performance surface coating material. Methods The OCr13NiSMo stainless steel substrate surface was preprocessed by washing with acetone （degreasing and derusting） and sandblasting （corundum particles）. NiTi/Ni, NiTi and NiTi/NiAl mixed coatings were prepared on the substrate surface by HVOF technology. Microscopic structure, morphology and phase composition of the three coatings were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Meanwhile hardness test was con- ducted on hardness tester to measure thickness and hardness of the three coatings. The topography of bonding interface between substrate and coating was observed. Characterization of the organizational structures of three coatings were compared and stu- died. Results The average hardness of NiTi/Ni, NiTi and NiTi/NiA1 were 574.3, 683.3 and 735 respectively; average thickness of NiTi/Ni, NiTi and NiTi/NiA1 coating specimens were 279.3μm, 270.5μm and 229.4μm respectively. The main organization of NiTi/Ni coating was Ni3Ti and Ni. The main organization of NiTi coating was NiTi（B2） phase, NiO, TiO and a small amount of NiOz The main organization of NiTi/NiA1 coating was NiTi, NiAl and a small amount of simple substance Ni and NiO2. Conclusion NiTi/NiA1 mixed coating has the highest hardness and densest bonding interface with the substrate and enjoys strong antioxidant activity and more uniform organization. In general, NiTi/NiAl mixed coating with stable performance is expected to become an even more desirable coating material in engineering application.