Characterization of porous NiTi alloys produced by SHS

Self-propagating High temperature Synthesis (SHS) was proposed as a suitable route for the production of porous NiTi alloys that show promising potential in biomedical applications. In this work NiTi products were obtained reacting cylindrical samples featured by different porosity. They were prepared by cold pressing elemental powders of Ni and Ti mixed at equiatomic stoichiometry. Tests were carried out adopting an experimental technique that permits to control the sample heating transient, the reaction initiation (driven by radiant energy) and to decouple these processes from the reacting front propagation regime. Moreover, the operating conditions, the initial porosity of the Ni and Ti pressed powders and sample size can be selected in order to obtain products having different characteristics. The results show that NiTi products with great porosity (up to 66%) can be obtained however; the presence of secondary undesired phases was detected too. DSC and SEM analyses of specimens produced at different operating conditions were reported.