The high temperature corrosion behaviour of Hf modified chromo-aluminised coatings produced by a single step process
The high temperature corrosion behaviour of Hf modified chromo-aluminised coatings produced by a single step process
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DOI：
10.1016/s0257-8972(96)03027-7
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发表时间：
1996-12
影响因子：
5.4
通讯作者：
H. Du;J. Kipkemoi;D. Tsipas;P. K. Datta
中科院分区：
文献类型：
--
作者：
H. Du;J. Kipkemoi;D. Tsipas;P. K. Datta
本文叙述了在RENE 80、INC718和2.25Cr-1Mo钢表面采用包层渗渗的方法，一次渗渗Cr、Al和Hf。对涂层合金进行了870和875℃的循环热腐蚀和循环氧化试验。表面处理合金在750℃H2/H2S/H2O环境下进行硫化，得到PS2= 10−6atm。PO2= 10−23atm。采用光学显微镜、扫描电镜、电子能谱、EDX和x射线衍射等手段对涂层和暴露试样进行了表征。循环热腐蚀和循环氧化试验表明，CrAlHf在合金表面的存在增强了合金的耐蚀性。稀土元素改性的铝化铬涂层具有良好的保护性能。然而，在INC718上镀CrAlHf涂层延迟了硫化气氛中难熔金属硫化物的形成，从而降低了其抗硫化性，而在2.25Cr-1Mo钢上镀CrAlHf涂层仅略微提高了其抗硫化性。
In this paper the introduction of Cr, Al and Hf into the surface of the RENE 80, INC718 and 2.25Cr—1Mo steel by pack cementation in a single step process has been described. The coated alloys were subject to cyclic hot corrosion and cyclic oxidation test at 870 and 875°C. The surface treated alloys were also sulphidised at 750°C in an environment of H2/H2S/H2O yielding PS2= 10−6atm. and PO2= 10−23atm. The coated and exposed specimens were characterised by optical microscope, SEM, EPMA, EDX and XRD. Cyclic hot corrosion and cyclic oxidation tests showed that the presence of the CrAlHf on the surface of the alloys enhanced their corrosion resistance. The rare earth element modified chromium aluminide coatings showed superior protectivity. However the CrAlHf coating on INC718 delayed the formation of the refractory metal sulphides in sulphidising atmosphere and thereby reduced its sulphidation resistance whilst the coating on 2.25Cr—1Mo steel only slightly increased its resistance to sulphidation attack.