Formation of iron oxide and iron sulfide at high temperature and their effects on corrosion. (1st May 2018)

• Record Type: Journal Article
• Authors: Gao, Shujun; Brown, Bruce; Young, David; Singer, Marc
• Is Part Of: Corrosion science. Volume 135(2018)
• Page Start: 167
• Page End: 176
• Publication Date: 2018-05-01
• Subjects: Hydrogen sulfide -- High temperature corrosion -- Iron oxide -- Iron sulfide; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2018.02.045
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: An inner thermodynamic less stable Fe3 O4 layer was found in high temperature H2 S corrosion. Iron sulfide polymorphs transformation at high temperature was observed for the first time. Different iron sulfide polymorphs have different roles in corrosion. Abstract: Recent high temperature H2 S corrosion study reported that a thermodynamically less stable iron oxide layer can also form in addition to iron sulfide. In this work, H2 S corrosion experiments were conducted at 120 °C for different exposure times, ranging from 1 to 21 days. The inner layer was identified by Transmission Electron Microscopy (TEM) as Fe3 O4 (magnetite); Fe3 O4 was always present over time despite it being less stable than iron sulfide. The observed formation sequence of iron sulfide at high temperature was mackinawite → troilite → pyrrhotite → pyrite. The role of the different corrosion product layers in corrosion is discussed.