CORROSION OF MAGNESIUM AND ITS CASTINGS STUDY OF PROPERTIES

Abstract

In the article, a number of issues related to the corrosion resistance of magnesium in the physiological environment were studied and analyzes were made based on the work of domestic and foreign scientists. The results of the study of methods for assessing the corrosive properties of castings with the addition of ligating elements to obtain biocompatible magnesium based castings were studied. It has been found that the strength and hardness of magnesium ingots can be improved by adding rare earth metals, and the corrosion resistance can also be increased. The main purpose of smelting is to improve mechanical properties, corrosion resistance and justify the cost of production. By adding alloying elements to Mg castings, mechanical properties such as strength, elasticity and resistance to biocorrosion can be improved. Alloying elements were selected taking into account not only their mechanical properties, but also the degree of their 
biocompatibility. Depending on the alloying metal, different structural characteristics of the Ingot 
can be obtained, including a small grain size distribution, as well as having a homogeneous structure. However, melt properties are also dependent on intermetallic compounds and microstructures. The corrosive behavior of magnesium ingots was assessed through electrochemical 
tests, which were carried out using a three-electrode cell system with a saturated calomel electrode (SCE) as the reference electrode and a platinum electrode  as the counter electrode and magnesium alloy samples as the working electrode. Potentiodynamic polarization curves were obtained by scanning ±500 MV against the open circuit potential (OCP) at a scan rate of 1.5 MV C-1 using an Electrochemical Workstation (VSP−300, biological, France). Given the re-passivity of MG alloys containing Sc, the samples were mechanically ground using 1200 grit SiC paper and HbSS absorbed for 1 hour to stabilize the open circuit. Corrosion current density icorr (ma cm-2) and 
corrosion rate (CR) were calculated by the Tafel method using EC-Lab software provided by biological. Three samples of each magnesium ingot were used to assess corrosion through electrochemical tests. The structural and morphological characteristics of pure magnesium and magnesium-based ingots were studied by X-ray diffraction analysis and scanning electron microscope methods.