Effect of Surface Modification on Corrosion Control of Type 409SS on U-bend Testing in Simulated Hydrothermal Liquefaction Processing Environments

Static autoclave • Cr coatings (EP and CR) improve the corrosion control compared to MG baseline • No statistical difference in static autoclave tests between EP and CR U-bend tests • Presence of S + Cl^- produced significant cracking in SS304; no cracks for SS409 • No significant galvanic effect on Cr coated samples • SS409-MG formed a weak defective scale in S containing environment • Cracks consisted of NixSy and a porous (Fe,Cr)3O4 spinel • Appreciable Ni content is undesirable in S containing environments.