Effect of silicon on the formation of protective scale on Fe-10Ni-10Cr-4Al alloy pre-oxidized at low oxygen pressure. (March 2023)

• Record Type: Journal Article
• Authors: Yuan, Manman; Zhao, Jinyu; Liu, Ya; Li, Danhong; Kolawole, Sharafadeen Kunle; Su, Xuping
• Is Part Of: Materials today communications. Volume 34(2023)
• Publication Date: 2023-03
• Subjects: Fe-Ni-Cr-Al-Si alloys -- FCC -- Pre-oxidation -- Diffusion -- Activity -- Al2O3; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.105167
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: The effects of Si on the high temperature oxidation of Fe-10Ni-10Cr-4Al-xSi (x = 0, 1, 2, 3 wt%) austenitic alloys were examined at 1000ºC by pre-oxidation under low oxygen pressure. The results showed that when Fe-10Ni-10Cr-4Al-xSi alloys were oxidized at 1000 ºC under oxygen pressure of 10 −20 atm for 5 h, without Si element, the oxidation products formed were continuous outer M2 O3 (M: Al and Cr) scale and a small amount of inner dendritic Al2 O3 . When Si was added, inner Al2 O3 increased obviously and SiO2 formed between M2 O3 and Al2 O3, and Cr2 O3 decreased and Al2 O3 increased in the external M2 O3 oxide layer. When 3 wt% Si was added, the oxide was only external Al2 O3 scale. The oxidation resistance of the alloys was improved with an increase in the Si content. Only external Al2 O3 scale on Fe-10Ni-10Cr-4Al-2Si alloy pre-oxidized at 1000ºC for 5 h under low oxygen pressure of 10 −30 atm. The addition of Si promoted the diffusion coefficient and activity of Al, increased the driving force of Al2 O3 formation and reduced the critical concentration for the transition from internal oxidation to external oxidation of Al2 O3. Graphical Abstract: ga1 Highlights: When Si content was 3 wt%, the oxide was only Al2 O3 . With the addition of Si, Cr2 O3 decreased and Al2 O3 increased in the external M2 O3 (M: Al and Cr) oxide layer. The critical Al content for forming external Al2 O3 in Fe-10Ni-10Cr-4Al-xSi austenitic alloys reduced with Si increased. When the oxygen pressure dropped to 10 −30 atm, only continuous Al2 O3 was formed on the surface of alloy.