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

Abstract

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.