中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 21 No. 11 November 2011 |
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. State Key Laboratory of Porous Metals Materials, Northwest Institute for Nonferrous Metal Research,
Xi’an 710016, China）
Abstract:The hot corrosion behaviors of as-cast and preoxidized Ni−xCr−6.8Al based alloys in the mixture of Na2SO4+25%NaCl at 873 K were studied. The results show that the mass loss of Ni−xCr−6.8Al based alloys decreases with the increase of Cr content. Preoxidation improves the resistance to corrosion regardless of the concentration of Cr. The kinetics of as-cast Ni−12Cr−6.8Al and Ni−16Cr−6.8Al based alloys fits the parabolic law well, while that of the as-cast Ni−20Cr−6.8Al based alloy fits the power law. The kinetics of all the preoxidized samples obey the logarithmic law. The mechanism of the as-cast alloys can be well explained by the acid-base melting model. The behavior of the preoxidized alloys is found to be mainly determined by the properties of the oxide layer formed during the preoxidation to a large extend.
Key words: Ni-Cr-Al based alloy; hot corrosion; Cr content; preoxidation; kinetics; corrosion mechanism
