Metallographic Documentation of the Degradation of Iron and Nickel Based Alloys in HCl and H₂S Containing Environments, between 480 – 680 °C

Abstract:

Corrosion behavior of the alloys 1.7386 (P9), 1.4462, 1.4841, 1.4959 (Alloy 800HT) and 2.4816 (Alloy 600) was tested for 24, 72 and 240 h between 480 – 680 °C. The testing gas atmosphere contained 3.8 vol. % HCl, 200 ppm H₂S and CO, CO₂ and N₂. It simulated conditions present in a thermal cracking process for post-consumer plastics. Samples were analyzed by metallography, SEM/EDX and XRD after corrosion experiments. Additionally, their mass loss during the test was evaluated. A multilayered structure of corrosion products grew on the samples during the corrosion experiments. The composition of the corrosion products depended not on the material, but on the testing temperature. At 680 °C chromium sulphide formed the outer layer, followed by a chromium oxide layer. Below these two layers a chlorine containing layer was observed. At 480 °C mainly nickel sulphide was detected, besides chromium oxide and iron- and chromium chloride. Especially at higher testing temperatures FeCl₂ was not observed directly on the samples, but as colorless crystals at the colder parts of the testing equipment. At 680 °C the mass loss of the samples decreased with increasing nickel content. However, this effect changed entirely at lower testing temperatures. At 480 °C 1.7386 and 2.4816 showed nearly the same mass losses.

• Periodical: Defect and Diffusion Forum (Volume 405)
• Pages: 26-32
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.405.26
• Online since: November 2020
• Authors: Alexander Schmid*, Gregor Mori, Roland Haubner
• Keywords: H₂S, HCl, High Temperature Corrosion, Nickel Based Alloys, Steel

References

[1] Plastics – the facts 2016: An analysis of the European plastics production, demand and waste date (2017).

[2] G. Sorell, Materials at high temperatures 14 (1997) 137-150.

[3] A. Zahs, M. Spiegel, H.J. Grabke, Materials and Corrosion 50 (1999) 561-578.

[4] D. Bramhoff, H.J. Grabke, H.P. Schmidt: in: The role of active elements, Ed. E. Lang, Elsevier Appl. Sc., (1989) 335-349.

[5] R. Prescott, F.H. Stott, P. Elliott, Corrosion Science 29 (1989) 465-475.

[6] D. Bramhoff, H.J. Grabke, H.P. Schmidt, Werkstoffe und Korrosion 40 (1989) 642-650.

[7] V.A.C. Haanappel, T. Fransen, P.J. Gellings, High Temperature Materials and Processes 10 (1992) 67-89.

[8] D. Bramhoff, H.J. Grabke, E. Reese, Werkstoffe und Korrosion 41 (1990) 303-307.

[9] A. Schmid, G. Mori, R. Haubner, M. Weil, S. Hönig, Materials and Corrosion 69 (2018) 1328-1337.

[10] A. Schmid, G. Mori, S. Hönig, M. Weil, S. Strobl, R. Haubner, Corrosion Science 139 (2018) 76-82.

DOI: 10.1016/j.corsci.2018.04.042

[11] W.T. Bakker, R.A. Perkins, EPRI Gasification Conference (1990).

[12] A. Schmid, G. Mori, E. Bucher, R. Haubner, Oxidation of Metals 91 (2019) 1-10.