The Control of Hot Corrosion in Marine Gas Turbines

Ingestion of sea salt and sulphur from fuel can lead to aggressive environments in gas turbines operating in marine conditions resulting in corrosion damage to hot end components, even in well-filtered engines. The nature of the environment in the engine and the factors which influence this are indicated. The chemistry of salt contaminant particles in the engine and combustion environments and temperature levels prevailing in naval engines are described in relation to the normal operating profile and the incidence of corrosion effects in relation to temperature. Results of rig evaluation of materials and coatings are given. Erosion resistance, the combined effects of erosion/corrosion and the mechanisms of hot corrosion are discussed together with the effects of material composition and the use of inhibition as a control procedure. The effects of a salt environment on the creep and stress-rupture behavior of superalloys are covered briefly.