A comparative study of boride coatings obtained by pack cementation method and by fluidized bed technology

Pack cementation is a surface treatment method which has been used, during the last 50 years, for the deposition of a wide range of coatings, among them borides, onto steel substrates. Recently, a new method for the deposition of hard and/or corrosion-resistant coatings, the fluidized bed technology, has been developed. In this paper, a comparative study of the boride coatings on low-carbon steel, which were obtained both by fluidized bed and pack cementation methods, was carried out. In both cases, the produced coatings are characterized by very good adherence and it was found that only one phase belonging to Fe 2B was formed during the treatments. The pack cementation procedure resulted in coatings with residual stresses and preferred orientation, while the fluidized bed borides are characterized by strain-free grains with random distribution.