Analysis of the initial oxidation layer of W-substituted alumina-forming heat-resistant steel

ABSTRACT

High-temperature oxidation behaviour of an alumina-forming austenitic (AFA, Fe_balance–20Ni–14Cr–2.5Al–0.15Si–2Mn–2.5Mo–0.9Nb, in wt%) steel and W-substituted AFA steel was examined. The isothermal oxidation tests were performed on the two steels at 780°C for 2 weeks in air, which indicated that the substitution of W for Mo was beneficial to improve the oxidation resistance of the AFA steel. After oxidation at 780°C for 30 min, more compact and protective initial oxide layer against cation diffusion was formed on the W-substituted AFA steel than that of the original AFA steel, which was considered to be responsible for the reduced weight gain after the long-term oxidation.

KEYWORDS:

• Alumina
• STEM
• stainless steels
• oxidation
• XPS

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Industrial Strategic Technology Development Program [20010778] funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea). This study was also supported by the Basic Science Research Program of the National Research Foundation (NRF) funded by the ‘Ministry of Science and ICT’ [NRF-2019R1C1C1010246].