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采用自蔓延高温合成法制备了适合大气等离子喷涂用的NiAl粉末,在45钢基体上制备NiAl涂层,研究了涂层在800℃的高温氧化特性和室温下浸泡在4wt%NaCl溶液中的耐腐蚀性,利用XRD、SEM技术分析了涂层的高温氧化和耐腐蚀机理。结果表明,自蔓延高温合成法制得的NiAl粉末主要由主相NiAl和少量Al3Ni相组成,制备的NiAl涂层致密且与基体结合良好;NiAl涂层在800℃氧化168 h增重13.8 mg.cm-2,约为45钢的1/10,提高了基体的高温抗氧化性,归因于高温氧化过程中涂层表面变成了一层薄薄的Al2O3保护膜;45钢和NiAl涂层在4wt%NaCl溶液中浸泡腐蚀42天后质量损失分别为5.34、1.23 mg.cm-2,这表明NiAl涂层具有较好的耐腐蚀性。
NiAl powder for atmospheric plasma spray coating was prepared by self-propagating high temperature synthesis method. NiAl coating was prepared on 45 steel substrate. The properties of high temperature oxidation at 800 ℃ and immersion in 4wt% NaCl solution at room temperature were studied Corrosive, the use of XRD, SEM analysis of the coating high temperature oxidation and corrosion resistance mechanism. The results show that the NiAl powder prepared by SHS synthesis is mainly composed of the main phase NiAl and a small amount of Al3Ni phase. The prepared NiAl coating is dense and well bonded with the substrate. The NiAl coating oxidized at 800 ℃ for 168 h, gaining 13.8 mg.cm -2, about 1/10 of that of 45 steel, which improved the high temperature oxidation resistance of the matrix due to the thin layer of Al2O3 protective film on the surface of the coating during high temperature oxidation. The mass loss after immersion etching in 4wt% NaCl solution for 42 days was 5.34 and 1.23 mg · cm-2, respectively, indicating that NiAl coating has good corrosion resistance.