NiAl intermetallic coatings elaborated by a solar assisted SHS process

A novel method to process intermetallic coatings by using a high flux solar concentrator has been studied. The main aim was to initiate an exothermic reaction in a mixture of powders (Ni and Al) and to obtain high quality coatings (NiAl) through a solar assisted SHS (self-propagating high temperature synthesis) process. Coatings have been processed in the form of tracks by scanning a concentrated solar beam across the specimen surface, thus modifying larger surfaces than those achieved with stationary treatment. Concentrated solar energy (CSE) not only provided the necessary heat to initiate the reaction but also permitted the propagation of the reaction through a reactant mixture of powders. This novel coating technology which combines SHS and CSE allows synthesizing the intermetallic coating in situ employing an energy saving process. By choosing an appropriate beam-sample interaction time it was possible to obtain homogenous, adherent and low porosity NiAl coatings. (C) 2006 Elsevier Ltd. All rights reserved.