Boride coatings on Ti-Ni alloys in a fluidized bed reactor

Boride coatings on Ti-Ni alloys were obtained using the fluidized bed technology. The as produced coatings are tested in a simulated environment in order to accelerate the corrosion rate and to study the corrosion and oxidation behavior of the samples. The oxidation resistance properties of the coatings were evaluated using a cycling oxidation testing system, with test conditions fixed as follow: maximum heating temperature 750 degrees C, cooling temperature 25 degrees C, heating time 30 min, cooling time 15 min and total number of 600 cycles. X-ray Diffraction patterns revealed the borides phases, which were formed in the coatings, as well as some protective oxide scales. SEM observation verified these results. In some cases the stress due to phase transformation introduces problems to the regular formation of the coatings.