Thin pack and chemical vapor deposited (CVD) aluminide coatings on commercial ferriticmartensitic
Fe-9Cr-2W steel are being investigated by creep and corrosion testing at 650°C. Mass gain
results indicate that these coatings are protective at 650°C in humid air. Comparison with bare material
shows that the coated region makes no contribution to the creep strength. The consumption of metal due
to the exposure in water vapor of uncoated specimens is compensated by the growth of a load-bearing
oxide scale. Pre-oxidation of the alloy in humid air also affects the alloy microstructure.