In-situ synthesis of novel Al-Fe-Si metallic glass coating by arc spraying

A novel in situ forming Al-Fe-Si metallic glass coating comprising partial nanoscale particles embedded in Al-based metallic glass matrix was synthesized by arc spraying process. The coating is adhering well and very compact with porosity of less than 2%. The volume fraction of metallic glass is 74.9% approximately. The onset crystallization temperature of the coating is 359 °C. The coating exhibits a high hardness (H = 4.25 GPa) and reduced Young's modulus (E = 235 GPa), together with good H/E, H2/2E and elastic recovery (η value). Dry sliding wear testing of the coating shows that the relative wear resistance of the coating is about 2.9 times that of the Al-6061 alloy under the same testing conditions. The dominating wear mechanism of the coating is a combination of brittle fracture delamination coupled with oxidative wear under dry sliding conditions. Meanwhile, potentiodynamic studies of the metallic glass coating in 0.6 M NaCl solution displays better corrosion resistance than that of Al alloyed coatings and EQ70 marine steel. In addition, the reasons actualizing the enhancement of the mechanical properties and corrosion resistance were elucidated.