Nanomechanical and Surface Properties of Co-Sputtered Polymorphous Nanostructured Thin Film Metallic Glasses for Surface Modification

Metallic glasses are amorphous materials that have shown prospects in biomedical due to their superior and unique mechanical, tribological, and bioactive properties. New functional surfaces polymorphic thin film metallic glasses (Ti-Fe-Cu, Zr-Fe-Al, and Zr-W-Cu) were deposited by co-sputtering of constituents from high purity (99.9%) targets. The thin film metallic glasses were deposited on stainless steel 316L (SS316L) and titanium alloy (Ti) substrates. Co-sputtering offers tuneable parameters (pressure, power, and time), which fosters high-quality polymorphic films of desired thickness and composition. Surface and nanomechanical properties of the films, including surface morphology, structure, mechanical, and tribological properties were investigated using SEM, AFM, XRD, XPS, nanoindentation, and scratch test. The coated substrates exhibit uniform nanostructured films with surface roughness in the range of 1.5 to 7 nm. The XRD spectra show a dominant amorphous glassy feature of the thin film on both substrates. Nanomechanical characteristics of the films suggest high wear resistance surface coatings with high film adhesion strength ranging between 624 - 2159 µN and 2273 - 2978 µN on SS316L and Ti substrates, respectively. Overall, the uniform polymorphic Ti-Fe-Cu, Zr-Fe-Al, and Zr-W-Cu thin films metallic glass with high adhesion on SS316L, and Titanium substrates are potential functional surfaces for biomedical applications.