Gas Hot Corrosion Behaviors of 9Cr18 Alloy

The gas hot corrosion behaviors of 9Cr18 alloy in high-temperature gas were studied by hot gas corrosion test and SEM observing. The results show that the gas hot corrosion products of the alloy could be divided into two layers, and there were large cracks between the two layers. The outside layer contained more chromium oxide and transversal cracks, and the internal layer contained less chromium oxide and was loose and porous. Sulfur compounds were found on the alloy surface and grain boundaries, and the alloy had an obvious tendency to intergranular corrosion. The corrosion mass gain per unit surface area and corrosion rate were rather fast in the early stage, and then tended to be slow and steady.