Present study aimed to optimize the HAE anodizing process to control the corrosion rate of pure magnesium in physiological environment. Magnesium, as a light and biocompatible metal, has great potential in biodegradable implant applications, but its uncontrolled corrosion in the body environment prevents its widespread use. In this study, five different electrolyte groups were designed by replacing aluminum hydroxide with aluminum nitrate and sodium silicate, and the effects of voltage (10 and 15 V) and time (10 and 15 min) on the anodic coating properties were investigated. The optimized sample in the electrolyte containing aluminum nitrate at 10 V, 10 min with a corrosion rate of 17.4 µA/cm² equivalent to 0.3-0.4 mm/year, the lowest porosity (8.8%), and a more uniform morphology were obtained. XRD and EDS analyses confirmed that the presence of nitrate ion led to the formation of the MgAl₂O₄ spinel phase and a denser oxide layer, which prevented the penetration of corrosive agents. Compared with other samples, the substitution of aluminum nitrate for potassium permanganate and aluminum hydroxide improved the anti-corrosion performance, while the simultaneous presence of sodium silicate and aluminum nitrate led to phase competition and decreased performance. The rate of corrosion found (0.3-0.4 mm/y) is in accordance with values regarding compatibility with the process of bone healing. Based on the observed degradation rate of this study, there appears to be a possible application in minimizing additional surgical procedures. Therefore, this research provides an effective step in the development of magnesium implants with better clinical performance.
Abdali et al. (Sun,) studied this question.