Investigation of Initial Transient Oxidation of Fe–xCr–6at.%Al Alloys Using Synchrotron Radiation During Heating to 1000 °C in Air

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• 作者：Suzue Yoneda ; Shigenari Hayashi ; Isao Saeki ; Shigeharu Ukai
• 关键词：Initial oxidation ; Third ; element effect ; Al2O3 scale ; Synchrotron radiation ; Cross ; term effect
• 刊名：Oxidation of Metals
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：86
• 期：3-4
• 页码：357-370
• 全文大小：2,006 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Inorganic Chemistry
  Tribology, Corrosion and Coatings
  Metallic Materials
  
• 出版者：Springer Netherlands
• ISSN：1573-4889
• 卷排序：86

文摘

The initial oxidation behavior of Fe–6Al alloys with different Cr contents (0–24 at.%) during heating to 1000 °C at 50 °C/min, followed by isothermal oxidation for 1 h, was investigated by means of synchrotron radiation in order to clarify the well-known beneficial effect of Cr on external Al₂O₃ scale formation. An external Al₂O₃ scale formed on the Cr-containing alloys but did not form on Fe–6Al. A corundum-type transient oxide scale, (Fe,Cr)₂O₃, formed on all alloys at about 500 °C, and an Al or (Al,Cr)-rich amorphous oxide layer was confirmed to form below the transient scale. This amorphous inner oxide layer was found to provide oxidation resistance up to at least 500 °C for the binary Fe–Al and about 900 °C for the ternary Fe–Cr–Al alloys. Internal precipitates of Al₂O₃ formed in the alloys when temperatures reached about 900 °C. The volume fraction of these internal precipitates increased with increasing alloy Cr content, which led to be inference that the outward diffusion flux of Al was enhanced by Cr addition.