CONTROLLED FORMATION OF SURFACE-LAYERS BY PACK ALUMINIZATION

Aluminum diffusion coatings on Armco iron were produced by a pack alum inization technique. Two different beds were applied: a high-activity bed containing pure aluminum as the coating source, and a low-activity bed containing Fe2Al5 as the source. In this work, the master alloy i tself was also prepared by a pack aluminization procedure using alumin um and iron powders. The effect of the bed content on the coating was examined. With the low-activity bed, the desired FeAl was formed as th e outermost coating layer. A set of complementary examination methods- XRD, SEM, EDX, RES and CEMS-were employed, providing detailed informat ion on the coating produced. (C) 1998 Elsevier Science S.A.