| Abstract: |
Plasma transferred arc hardfacing (PTA) is an excellent tool for surface tailoring as it allows for the manipulation of coatings chemical composition. In particular in-situ alloy development can be achieved during the deposition of different powder mixtures. In this work powder mixtures of Ni-Al, Nb-Al and Fe-Al were deposited by PTA. Coatings were characterized for their mechanical features evaluated by Vickers microhardness under 300gf load, nano- (0,04gf) and macro- (12kgf) scratch tests and pin-on-abrasive disc tests under 1kgf. Results showed that hardness varied according to the chemical composition of the deposited powder mixtures, with the Fe based deposits exhibiting the lower hardness (below 400Hv) and the Nb-based deposits reaching 900HV. Hardness as measured by nano- and macro scratch tests followed the same tendency and decreased with Vickers microhardness reduction. Within each alloy system, the harder the coating the better the wear resistance. However when comparing the full set of coatings the Nb based coatings exhibited a superior performance and the Ni based deposits the poorer wear resistance. This behaviour can be associated with the significant deformation observed along the scratches done on the latter surfaces.
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