Formation of a protective layer against corrosion on Mg alloy via alkali pretreatment followed by vanillic acid treatment

Abstract

Although Mg alloy possesses high specific strength, low density, and good biocompatibility, poor corrosion resistance hinders its further applications. In the present study, an innovative protective layer against corrosion was prepared on the AZ31 Mg alloy via alkali pretreatment followed by vanillic acid treatment. The alkali pretreatment supplied –OH for the AZ31 Mg alloy surface to react with vanillic acid. The vanillic acid treatment played a crucial role in enhancing the corrosion resistance due to the excellent ability to act as a barrier and retard aqueous solution penetration, which effectively isolated the underlying Mg alloy from the corrosive environment. The corrosion current density of alkali and vanillic acid‐treated Mg alloy (AZ31V) almost showed two orders of magnitude lower values in comparison with that of the AZ31 Mg alloy, and the corrosion potential of AZ31V Mg alloy increased from −1.41 to −1.25 V. The immersion tests proved that there was no occurrence of severe corrosion. Hence, the alkali pretreatment and vanillic acid treatment may represent a promising method to improve the corrosion resistance of Mg alloy.

Corrosion Behavior in Magnesium-Based Alloys for Biomedical Applications

“…Surface modification is an effective approach to improving corrosion resistance and surface bioactivity [ 254 , 255 , 256 ]. It can be used to improve surface integrity, fabricate physical barriers, and isolate the underlying Mg matrix from corrosive media, thereby maintaining the mechanical integrity of Mg-based alloys before healing is completed.…”

Recent Progress in Surface Modification of Mg Alloys for Biodegradable Orthopedic Applications

“…The in vivo test on the rat model substantiates uniform corrosion without any subcutaneous gas cavity formations. Li et al (2020b) reported that the excess hydroxyl ions formed on the AZ31 alloys while treating them with NaOH acted as a corrosion barrier and promoted the reaction with vanillic acid treatment. However, like acid treatment, the stability of the conversion coating by alkali treatment is a crucial concern, and hence, they are better suggested as a pretreatment process.…”

Ultrasonic Treatment Induced Fluoride Conversion Coating without Pores for High Corrosion Resistance of Mg Alloy

“…As one of the lightweight metals with low density and high mechanical properties, Mg alloy has attracted significant interest in the automotive and aviation industry. However, the lightweight applications of Mg alloy have been hindered due to the highly corrosive tendency [1][2][3]. Mg alloy is extremely sensitive to galvanic corrosion, leading to a rapid corrosion [3][4][5].…”

“…However, the lightweight applications of Mg alloy have been hindered due to the highly corrosive tendency [1][2][3]. Mg alloy is extremely sensitive to galvanic corrosion, leading to a rapid corrosion [3][4][5]. In addition, Mg alloy also has a tendency of localized corrosion, leading to a quick failure of mechanical properties [6,7].…”