摘要
采用SEM、EDS和XRD等方法,研究了HP40Nb钢热浸镀Al-10Si-1Ce合金的初始镀层、扩散处理渗层、高温氧化渗层的微观组织特征和抗高温氧化性能。结果表明:热浸镀层由初生α-Al,(α-Al+Si)共晶组织的外层和(Fe,Cr,Ni)2(Al,Si)5相的内层组成。热浸镀试样分别在800、900、1 000℃下进行4h扩散处理后,渗层中各层呈现不同的显微组织特征,且表面生成了不同氧化物:θ-Al_2O_3,θ-Al_2O_3+α-Al_2O_3,α-Al_2O_3。不同温度扩散处理的试样经1 000℃/360h高温氧化后,渗层均由外层(NiAl+Cr3Si)和内层(σ、α+Ni3Al)组成。1 000℃/4h扩散处理的试样在高温氧化过程中平均氧化速率最小、抗氧化性能最好,其原因是表面致密的单一α-Al_2O_3阻碍了氧化的进行。
In order to improve the high temperature oxidation and carburization resistance of HP40Nb steel, experiment of steel was coated by hot-dipping into a molten bath containing Al-10Si-Ce. The effect of diffuse treatment on hot-dip aluminizing steel microstructure and oxidation resistance behavior at high tem- perature was studied by means of SEM, EDS and XRD. The results show that after hot-dip Al-10Si-ICe treatment, the coating layer consisted of inner layer[ (Fe, Cr, Ni) 2 (A1, Si) 5 -] and outer layer[primary α-Al, (α+Si)eutectic structure-]. After diffusion at 800, 900, 1 000℃ for 4h, the coatings had different microstructure characteristics , different oxides were formed on the surface: θ-Al2O3,θ-Al2O3 + α-Al2O3, α-Al2O3. After the cyclic oxidation test at 1 000℃ for 360h,the coatings consisted of outer layer(NiAl+Cr3Si) and inner layer(σ,α+Ni3Al). In the oxidation, the hot dipped Al-10Si-1Ce HP40Nb steel with the diffuse treatment of 1 000℃ / 4h had the minimum oxidation rate and best oxidation resistance. The reason was that the compact α-Al2O3 layer of the coating surface hindered the continuous oxidation.
出处
《常州大学学报(自然科学版)》
CAS
2017年第1期1-6,共6页
Journal of Changzhou University:Natural Science Edition
基金
国家自然科学基金项目(51671038)
关键词
HP40Nb钢
热浸镀
高温氧化
微观组织
HP40Nb steel
hot dipping
high temperature oxidation
microstructures