Mechanical Property of Magnesium Alloy Surface with Dense Oxide

Abstract

Low Al single-phase magnesium alloy surfaces with dense magnesium oxide films were uniformly formed. The films were deposited with a radio frequency magnetron sputtering process with a planar magnetron sputtering system. The thickness of deposited magnesium oxide thin films was around 240 nm. According to the XRD results, a magnesium oxide phase film was formed on the substrate. The surface was uniform, and no cracks or exfoliation were observed. The deposited magnesium oxide film did not have any cracks or pores, and the surface of the sample was covered by magnesium oxide. The hardness of the magnesium oxide-coated magnesium alloy reached around Hv200, while that of the uncoated Mg-alloy was around Hv80. Moreover, the Vickers indenter under a 10-mN load indented the magnesium alloy substrate coated with the magnesium oxide film to a depth of around 640 nm, while that for the uncoated magnesium alloy substrate was around 620 nm. Meanwhile, the elasticity value for the magnesium alloy substrate coated with magnesium oxide film was around 5.3×1010Pa, while that of the uncoated magnesium alloy substrate was around 4.2×1010Pa.

A comprehensive review of properties of the biocompatible thin films on biodegradable Mg alloys

“…But the coating without fluoride revealed a layer with surface defects and with a lower hardness and elastic modulus [21]. Watazu and Sonoda [22] sputtered MgO onto AZ31 alloy and delivered a more excellent elasticity of 5.3 × 10 10 Pa, and the coatings were stress-resistant and crack-resistant [22]. In addition, the magnesium oxide film had compressive stress and high density.…”

“…The oxide layer formed naturally on the magnesium is of low density with poor corrosion resistance. But the oxide coatings coated onto it provide good chemical inertness and hardness and impart both corrosion and abrasion resistance [22]. Different surface modification techniques were employed to form an oxide thin film layer on the Mg alloy substrates, and various types of electrolytes were used for the corrosion studies [39].…”