Cyclic oxidation performance of a CVD-FBR aluminised 18Cr-8Ni Stainless steel

Stainless steel is still the material of choice because it finds numerous applications and its good performance in different environments and its relatively low price. However, its poor mechanical strength and the formation of volatile CrO 3 oxide under oxygen environments restrict their upper operation temperature to less than 950° C. Thus, the application of aluminide coatings may increase the upper limit of temperature of these steels in case they did not have to withstand important mechanical loads. Chemical Vapour Deposition in Fluidised Bed Reactors (CVD-FBR) has been used to coat the AISI 304 stainless steel at temperatures of 525° C for 1.5 hours followed by a heat treatment up to 900° C under inert Ar gas. Cyclic oxidation experiments of both coated and uncoated specimens have been performed at 950° C under atmospheric pressure of air. The results will show that the application of the CVD-FBR is very promising as a surface modification technology since the behaviour of the coated specimens is much better than that of the uncoated ones.