Tailoring biomineralization and biodegradation of Mg–Ca alloy by acetic acid pickling

Abstract

Magnesium and its alloys are suitable candidates for developing biodegradable metallic implants. However, the rapid degradation of these alloys in the physiological environment is a major limitation for such applications. In this work, Mg-Ca alloy was chemically treated with acetic acid and its effects on degradation behaviour were studied using simulated body fluid (SBF). The surface morphology and composition of the acid pickled samples were investigated using a scanning electron microscope (SEM) and infrared spectroscopy (IR). The degradation rate was analysed by conducting potentiodynamic polarization (PDP) and immersion tests. The results show that optimum acetic acid treatment improved the corrosion resistance by acid etching and formation of magnesium acetate layer. The treated samples also exhibited enhanced biomineralization and developed calcium phosphate layer on the surfaces during immersion tests. It is proposed that acetic acid pickling can be used as a reliable technique for surface modification as well as for pre-treatment of magnesium alloys to make them suitable for degradable metallic implant applications.

Chromate-Free Corrosion Protection Strategies for Magnesium Alloys—A Review: PART I—Pre-Treatment and Conversion Coating

“…In spite of the diverse variety of organic acids, only a minimal number of them have been investigated as the main component of pickling solutions. Among all the organic acids, acetic acid has been studied and used considerably more so than other organic acids [ 62 , 69 , 71 , 72 , 105 , 106 ], and even the mixture of 115–300 g/L acetic acid + 30–75 g/L NaNO 3 has been offered as a suitable pickling solution for wrought magnesium alloys in standards and handbooks [ 107 , 108 ]. Knowing the significant importance of the acid pickling step toward the improvement in the corrosion protection properties of bare and coated Mg alloys, the currently available knowledge about the use of organic acids as the pickling solutions is notably scant; and further research on the potential organic acids in this regard will generate enormous added value for corrosion protection technologies.…”

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

“…In addition, the thin films formed on the surface also help in passivation and thereby reduce the degradation. The treatment also helps in improving the surface energy favorable for cell adhesion and proliferation (Gawlik et al, 2019;Rahim et al, 2020). Mao et al (2013) treated Mg-Nd-Zn-Zr alloy in 40% (vol.)…”

Surface engineering of pure magnesium in medical implant applications

“…Among the various commonly used medical metal implants, Mg and its alloys demonstrate outstanding mechanical characteristics, biodegradability, and the ability for degradation by-products to be metabolically excreted from the body without adverse effects [ [15] , [16] , [17] , [18] ]. Currently, medical Mg implants primarily include Mg alloys such as WE43 [ [19] , [20] , [21] , [22] , [23] , [24] ], AZ31 [ [25] , [26] , [27] , [28] , [29] ], Mg-Ca [ [30] , [31] , [32] , [33] ], and MgZnCa [ [34] , [35] , [36] ]. However, the incorporation of other metallic elements into Mg alloys does not necessarily ensure favorable biocompatibility of these added elements and complete in vivo degradation.…”