LOW ALUMINUM CONTENT PERMEATION BARRIER COATINGS FOR DIN-1.4914 MARTENSITIC STEEL (MANET)

This paper describes the production and permeation measurements of three different aluminide coatings on the surface of MANET II stainless steel. The coatings were produced by vacuum plasma spraying pure aluminium (approximate to 100 mu m) on to the steel, which was subsequently heat treated to produce an aluminide layer on the MANET. The relationship between the aluminum content of the coatings and their effectiveness as permeation barriers, due to the greater or lower resistance to crack formation was manifest. The coatings with a lower aluminum content presented the largest permeation reduction (2 orders of magnitude).