Corrosion Behavior of Stainless Steels and Superalloys at 800°C and 900°C in an Oxidizing Environment

ABSTRACT Cement pre‐heaters and calciners suffer extreme degradation in harsh environments. This study presents high‐temperature corrosion behavior of 22 alloys from stainless steels to Ni‐based superalloys, at 800°C and 900°C. Using simulated flue‐gas with KCl and K 2 SO 4 salts to replicate industrial conditions, results showed that including Ni, Mn, and Mo, significantly reduced mass loss from 21.9 mg cm −2 to 0.53 mg cm −2 . Linear regression identified Mn and Ni as having the most positive impact on protection. Mn forms Mn 3 O 4 , stabilized by high‐melting point MnO (1945°C), creating a robust barrier against alkali chloride‐salts. HSC chemistry equilibrium simulations revealed that chromium becomes non‐protective in these environments by forming soluble potassium chromates, resulting in porous scales. Molybdenum forms K 2 MoO 4 which unexpectedly enhances durability through complex interactions. By correlating the mass ratio of key alloying elements to total mass loss, this research establishes a scientific framework for selecting superior alloys for industrial field testing along with providing possible primary reactions.