Effect of feedstock powder on NiAl intermetallic compounds coating by cold spray

Abstract

In cold spray, feedstock powders are accelerated by supersonic jet with solid phase and deposited onto substrate. Compared with the conventional thermal spray, the dense coatings can be prepared without oxidation and decomposition of original powders.
In this study, two types of Ni-Al mixture powders with different mixture form were used to fabricate Ni-Al composite coatings by cold spraying. Subsequently the coatings were annealed to synthesize NiAl intermetallic compounds.
As a result, a dense NiAl intermetallic compounds coating was fabricated by using the Ni-Al mechanical milling powder. Moreover, the adhesive strength and micro vickers hardness of this coating is found to be higher than that formed by Ni-Al blended powder.