Surface Properties Contrast between Al Films and TiO2 Films Coated on Magnesium Alloys by Magnetron Sputtering

Abstract

Al films and TiO 2 films were separately coated on AZ31 magnesium alloy substrates by means of magnetron sputtering method. The surface properties of the samples were explored and compared. Scanning electron microscope (SEM) observed the compact structure characteristics of as-deposited Al films and TiO 2 films. After heat treatment under 200ºC for half an hour the films kept the compact structure characteristics and there didn't exist structural defects on the surface of the films. Nano-indentation measurement results display that the micro-hardness of as-deposited Al film and TiO 2 film reaches about 1.90 Gpa and 1.51 Gpa, separately. Al film is a bit harder than TiO 2 film. Finally, the corrosion experiments in simulated body fluid initially indicate the different corrosion properties for Al film and TiO 2 film. Al film presents more effective anti-corrosion properties than TiO 2 film.

The current trends of Mg alloys in biomedical applications—A review

“…One of the advantages of PVD is that it involves no chemical interaction between the target and the substrate. Other advantages include uniform and adherent layers and its convenience to control the film thickness …”

“…For Mg substrates, the preferred technique is sputtering. In literature, HA sputtered Mg alloys have been mostly investigated, though there are some studies in which Al, TO, and TiO 2 sputtered Mg surfaces have also been studied . In a recent study, a film of the thickness of 980 ± 50 nm was deposited on Mg alloy AZ91 by sputtering Ca‐P using a radio frequency (RF) magnetron source at 500 W for 8 h. The investigation of mechanical properties with nanoindenter witnessed a significant increase in the values of nanohardness and Young's Modulus as compared to bare AZ91 sample .…”

“…The results showed an improvement in the corrosion potentials when compared to untreated AZ91 samples . The sputtering is not limited to only HA sputtered layer but it has been also used to coat other biocompatible materials on Mg alloys . A tantalum oxide (TO) thin film with a thickness of 1.48 ± 0.02 μm was deposited on ZK60 alloy in a vacuum of 6.5 × 10 −4 Pa at 100 W for 3 h using a Ta target in DC sputtering gun.…”