Magnetron Sputtered Non-Toxic and Precious Element-Free Ti-Zr-Ge Metallic Glass Nanofilms with Enhanced Biocorrosion Resistance

The chemical composition and structural state of advanced alloys are the decisive factors in optimum biomedical performance. This contribution presents unique Ti-Zr-Ge metallic glass thin-film compositions fabricated by magnetron sputter deposition targeted for nanocoatings for biofouling prevention. The amorphous nanofilms with nanoscale roughness exhibit a large relaxation and supercooled liquid regions as revealed by flash differential scanning calorimetry. Ti68Zr8Ge24 shows the lowest corrosion (0.17 mu A cm(-2)) and passivation (1.22 mu A cm(-2)) current densities, with the lowest corrosion potential of -0.648 V and long-range stability against pitting, corroborating its excellent performance in phosphate buffer solution at 37 degrees C. The oxide layer is comprised of TiO2, TiOx and ZrOx, as determined using X-ray photoelectron spectroscopy by short-term ion-etching of the surface layer. The two orders of magnitude increase in the oxide and interface resistance (from 14 to 1257 omega cm(2)) along with an order of magnitude decrease in the capacitance parameter of the oxide interface (from 1.402 x 10(-5) to 1.677 x 10(-6) S s(n) cm(-2)) of the same composition is linked to the formation of carbonyl groups and reduction of the native oxide layer during linear sweep voltammetry.