High-Velocity Arc Spraying of Fe-based Metallic Glasses with High Si Content.

Various feedstocks are available for the thermal spraying of metallic glasses, which are often alloyed with high amounts of cost-intensive elements. In previous steps, a novel, economic Fe-based metallic glass alloy with a high Si content has been developed using melt spinning. The aim of this work is to investigate the application of the alloy using the high-velocity arc spraying (HVAS) process. On this basis, four cored wires are manufactured with the aim of maximizing in situ intermixing and amorphous phase formation during the spraying process. The cross sections of the resulting coatings are analyzed by light microscopy, scanning electron microscopy and Vickers hardness testing. Phase analysis on the coatings is conducted with regards to the formation of amorphous phases using x-ray diffractometry (XRD) and differential scanning calorimetry. The XRD patterns indicate a mixture of (nano-) crystalline ferrite and amorphous phases. In particular, the coating manufactured with wire No. 1, a Fe-B-Si-C-Nb composition, exhibited good intermixing and a highly amorphous structure. This work demonstrates that glassy metallic coatings can be produced by means of HVAS using Fe-based cored wires comprising of conventional filler materials. A successful intermixing, in situ alloying and the subsequent formation of amorphous phases is achieved. [ABSTRACT FROM AUTHOR]