Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

Jaromír Wasserbauer,Pavel Doležal,Jozef Minda,Jakub Tkacz,Karolína Slouková,Stanislava Fintová,Juliána Drábiková

doi:10.3390/met7110465

Abstract

The electrochemical corrosion characteristics of AZ31 and AZ61 magnesium alloys were analyzed in terms of potentiodynamic tests and electrochemical impedance spectroscopy. The influence of the solution composition and material surface finish was examined also through the analysis of corrosion products created on the samples’ surface after electrochemical measurements in terms of scanning electron microscopy using energy-dispersive spectroscopy. Obtained data revealed the differences in the response of the magnesium alloys to enriched Hank’s Balanced Salt Solution—HBSS+ (with Mg2+ and Ca2+ ions) and Hank’s Balanced Salt Solution—HBSS (without Mg2+ and Ca2+ ions). Both examined alloys exhibited better corrosion resistance from the thermodynamic and kinetic point of view in the enriched HBSS+. AZ61 magnesium alloy reached higher values of polarization resistance than AZ31 magnesium alloy in both the used corrosion solutions. Phosphate-based corrosion products were characteristic for the AZ31 and AZ61 alloys tested in the HBSS (without Mg2+ and Ca2+ ions). The combination of phosphate-based corrosion products and clusters of MgO and Mg(OH)2 was typical for the surface of samples tested in the enriched HBSS+ (with Mg2+ and Ca2+ ions). Pitting corrosion attack was observed only in the case of enriched HBSS+.

Highlights

Magnesium is an essential element for living organisms, for technical purposes is the magnesium used mainly in the form of alloys
The microstructure of the AZ31 magnesium alloy is consisted of polyhedral grains of the
The microstructure of the AZ31 magnesium alloy is consisted of polyhedral grains of the substitutional solid solution which

Summary

Introduction

Magnesium is an essential element for living organisms, for technical purposes is the magnesium used mainly in the form of alloys. Alloying elements improve magnesium mechanical properties and it can be used to control its reactivity. Due to the suitable combination of physico-mechanical properties, biocompatibility and non-toxicity specific magnesium alloys are investigated for medical applications. In the case of orthopedic implants physical and mechanical properties of magnesium alloys are important. These properties are similar to the properties of a human bone (e.g., density, compressive yield strength, ultimate tensile strength). Magnesium alloy implants are biocompatible and biodegradable [1,2,3,4,5,6,7,8,9,10,11]. As a result of chemical reactions with the biological environment non-toxic corrosion products are created on the surface of the implants

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