Hardfacing allows to protect components with coatings exhibiting very distinct properties from those of the substrate. This procedure maintains the structural properties of the substrate and optimizes resistance of the surface to the working environment. A step towards enhanced performance of components can be achieved if high hardness and chemical inertia, low weldability materials can be used. In-situ aluminide processing, involving the development of aluminide during the deposition by Plasma Transferred Arc of powder mixtures is reviewed. Analysis of coatings exhibiting a gradient of properties obtained by the in-situ synthesis of an alumina and an aluminide bond-layer was carried out. The synthesis of the different layers occurred during the deposition of a mixture of quartz and Al powders on a steel and a Ni based substrates. The main features of the layered coatings are described and their microstructure analyzed. Preliminary results of abrasive sliding wear tests showed a 5x reduction in mass loss compared to the behavior of Co-based coatings.
Coatings; Plasma Transferred Arc; Aluminides; Alumina
