Comparative investigation of oxidation behavior and hot corrosion behavior in NaCl–Na2SO4 mixture for a Ti2AlNb based alloy at 1023 K

Xiang, Jiayi; Xie, Fei; Wu, Xiangqing; Wang, Shaoqing

doi:10.1016/j.intermet.2021.107151

Cited by 13 publications

(1 citation statement)

References 43 publications

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“…In addition, the distribution areas of element Na and element Nb show a high degree of consistency on the surface, which combined with Figure 8d, indicating that the non-protective corrosion products (NaNbO 3 , Na 2 TiO 3 and AlNbO 4 ) were significant factors in the corrosion damage that occurred on the alloy surface. The standard Gibbs free energy for the reaction of 1 mol O2 with the elements in the Ti2AlNb alloy to form the corresponding oxides at 650 °C has been reported: ∆G0 Al2O3 (−902 KJ/mol) < ∆G0 TiO2 (−759 KJ/mol) < ∆G0 Nb2O5 (−581 KJ/mol) [25]. However, the growth of oxidation products is not only associated with thermodynamics, but also with growth kinetics.…”

Section: Resultsmentioning

confidence: 99%

Oxidative Corrosion Mechanism of Ti2AlNb-Based Alloys during Alternate High Temperature-Salt Spray Exposure

et al. 2022

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This study investigates the corrosion damage mechanisms of Ti2AlNb-based alloys under high temperature, salt spray and coupled high temperature-salt spray conditions. This alloy was analysed in detail from macroscopic to microscopic by means of microscale detection (XRD, SEM and EDS). The results indicated that Ti2AlNb-based alloy surface oxide layer is dense and complete, and the thickness is only 3 µm after oxidation at 650 °C for 400 h. Compared to the original sample, the production of the passivation film resulted in almost no damage to Ti2AlNb-based alloy after 50 cycles of salt spray testing at room temperature. The tests showed that Ti2AlNb alloy shows good erosion resistance at 650 °C and in salt spray. However, this alloy had an oxide layer thickness of up to 30 µm and obvious corrosion pits on the surface after 50 cycles of corrosion under alternating high temperature-salt spray conditions. The Cl2 produced by the mixed salt eutectic reaction acted as a catalytic carrier to accelerate the volatilisation of the chloride inside the oxide layer and the re-oxidation of the substrate. In addition, the growth of unprotected corrosion products (Na2TiO3, NaNbO3 and AlNbO4) altered the internal structure of the oxide layer, destroying the surface densification and causing severe damage to the alloy surface.

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Section: Resultsmentioning

confidence: 99%

Oxidative Corrosion Mechanism of Ti2AlNb-Based Alloys during Alternate High Temperature-Salt Spray Exposure

et al. 2022

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Effect of special grain boundary on hot corrosion path in Incoloy825 alloy

et al. 2022

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Microstructure and Hot Corrosion Property of a Si–Co–Y Diffusion Coating Deposited on TiAl–Nb Alloy

Li,

Lv,

Xie

et al. 2023

High Temperature Corrosion of mater.

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Si-Co-Y diffusion coatings were deposited on TiAl-Nb alloy using pack cementation process. The influence of activators and deposition temperatures on the coating structures was investigated, alongside the coating formation process and hot corrosion performance of the optimized coating in molten salt of 25%NaCl+75%K2SO4 at 850 ℃. The results show that a dense and compact Si-Co-Y diffusion coating can be prepared on TiAl-Nb alloy, with a multi-layered structure including an outmost layer of (Ti,X)Si2 (X represents Co, Al, Nb, Y), an outer layer composed of TiSi2+Ti5Si4+Ti5Si3 mixtures, a middle layer of Ti5Si3, and an inner layer of TiAl2. The coating prepared with AlCl3•6H2O and NH4Cl had many pores. Increase in deposition temperature led to a higher coating growth rate within the range of 1050-1100 o C, but temperature exceeding 1100 ℃ caused the formation of intensive holes in the coating. Hot corrosion tests at high temperatures proved that the Si-Co-Y diffusion coating prepared on TiAl-Nb alloy exhibited excellent hot corrosion resistance in 25%NaCl-75%K2SO4 molten at 850 o C. A protective hot corrosion product scale composed of a TiO2+Na2SiO3+Na2TiO3 outer layer and an Al2O3 middle layer, formed on coating after hot corrosion for 50 h. The scale can effectively inhibit the inward diffusion of corrosion medial of O, Cl and S elements.

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Comparative investigation of oxidation behavior and hot corrosion behavior in NaCl–Na2SO4 mixture for a Ti2AlNb based alloy at 1023 K

Cited by 13 publications

References 43 publications

Oxidative Corrosion Mechanism of Ti2AlNb-Based Alloys during Alternate High Temperature-Salt Spray Exposure

Oxidative Corrosion Mechanism of Ti2AlNb-Based Alloys during Alternate High Temperature-Salt Spray Exposure

Effect of special grain boundary on hot corrosion path in Incoloy825 alloy

Microstructure and Hot Corrosion Property of a Si–Co–Y Diffusion Coating Deposited on TiAl–Nb Alloy

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