摘要
采用大气等离子喷涂工艺在Ni基高温合金上制备NiCrAl涂层,并研究了该涂层在盐雾腐蚀和氧化条件下的耐腐蚀性能。通过对NiCrAl涂层盐雾腐蚀前后的极化曲线分析,可知NiCrAl涂层盐雾腐蚀后的腐蚀电位变得更负,腐蚀电流密度变得更大,说明经过盐雾腐蚀后的NiCrAl涂层的耐腐蚀性明显下降。由SEM观察可知,NiCrAl涂层经过盐雾腐蚀后表面和内部都出现了大量的裂纹,组织变得疏松,遭到严重腐蚀,涂层失去保护能力。经EDX分析可知,腐蚀产物的化学通式为MexOyClz。经过预氧化的NiCrAl涂层由于形成了θ-Al2O3膜,耐腐蚀性能增强。
NiCrAl coatings were prepared on Ni-based superalloy through Atmospheric Plasma Spray (ASP), and the corrosion resistance of the coatings under the conditions of salt spray test and high-temperature oxidation was investigated. From the Tafel polarization curve of NiCrAl coatings before and after the salt spray test, it is shown that the corrosion potential of NiCrAl coatings becomes smaller while the corrosion current density becomes larger, indicating that the corrosion resistance of NiCrAl coatings after the salt spray test is decreased obviously. SEM images show that after the salt spray test, the corrosion of surface of the NiCrAl coatings is serious resulting from the appearance of many cracks and the loose microstructure, so the coatings have no protective capability. EDX analyses reveal that corrosion products are Me(x)O(y)Cl(z). After the thermal treatment at 1000 degrees C for 15 h, the corrosion resistance of NiCrAl coatings is enhanced because of the formation of theta-Al(2)O(3) film..
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2010年第12期2181-2184,共4页
Rare Metal Materials and Engineering
基金
教育部新世纪优秀人才计划(NCET2006)
