Devitrification of arc-sprayed FeBSiNb amorphous coatings: Effects on wear resistance and mechanical behavior

FeBSiNb amorphous coatings were synthesized by arc spray processing. The effects of annealing treatments on the microstructure, elastic and mechanical properties of the coatings were investigated. Annealing below 650 °C induces the formation of α-Fe phase nanocrystals. Annealing at 650 °C promotes the formation of Fe3B, Fe23B6 phases and α-Fe solid solution. The as-sprayed coating displays ultra-high hardness (H > 16 GPa), high reduced Young's modulus (Er > 210 GPa) and good wear resistance. These properties are further improved after annealing treatments (H > 20 GPa and Er > 260 GPa are achieved in the fully crystallized coating). The mechanical hardening is accompanied with an increase of the ratio of hardness to elastic modulus (H/Er), the yield pressure (H3/Er2) and the elastic recovery (η value). The different microstructural mechanisms responsible for these annealing-induced changes in mechanical and elastic properties are discussed.