Fabrication and characterization of supersonic plasma sprayed Fe-based amorphous metallic coatings

Fe-based amorphous metallic coatings with a nominal composition of Fe48Cr15Mo14C15B6Y2 were fabricated by supersonic plasma spraying (SPS). The effects of the Ar flow rate and spraying power on the microstructure and amorphous content of the coatings were systematically investigated. The thermal stability, microhardness and porosity of the coatings were also experimentally determined and characterized. The results demonstrate that the coatings present denser layered structure with a thinner intersplat region, and the elements inter-diffusion zone exist between the coatings and the substrate. It is also found that the amorphous content of coatings is as high as 90% and the coatings exhibit high thermal stability with an onset crystallization temperature of 963 K. The amorphous content and microhardness initially increase and then decrease gradually with the increase of Ar flow rate whereas the porosity decreases firstly and then increases. However, the amorphous content and micro hardness increase with the increase of the power whereas the porosity decreases. In particular, the amorphous content and microhardness can be reached 96.78%, and 1005 HV0.1 respectively, whereas the porosity is only 0.85% at the spraying power of 62 kW and the Ar flow rate of 110 L/min. (C) 2016 Elsevier Ltd. All rights reserved.