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2 Journal of Achievements in Materials and Manufacturing Engineering

2 2013

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Structure and corrosion properties of Mg70-xZn30Cax(x=0.4) alloys for biomedical applications

Nowosielski R., Cesarz K., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

2013

Vol. 58, nr 1

7--15

Purpose: The main objective of the paper was to investigate the structure and corrosion properties of amorphous and crystalline Mg-based alloys for biodegradable implants. This paper presents a preparation method and the structure, microhardness and corrosion properties characterization of Mg70Zn30and Mg66Zn30Ca4 alloys in the form of plates. Design/methodology/approach: The studied samples were prepared by the pressure die-casting to copper mould. The structure of the both alloys was examined by X-ray diffractometry (XRD) and a scanning electron microscope (SEM). The thermal properties of the samples were examined using a differential scanning calorimeter (DSC). In addition, corrosion properties research (immersion tests) were performed in a physiological fluid. Microhardness was measured using the Vickers microtester. Findings: The results of X-ray diffraction investigations confirmed that the sample of Mg66Zn30Ca4 alloy is amorphous and sample of Mg70Zn30 alloy has crystalline structure. Immersion tests of both samples have shown homogeneous progress of corrosion. The changes of a structure caused by calcium addition resulted in an increase of microhardness for sample Mg66Zn30Ca4 compared with the sample of Mg70Zn30 alloy. Research limitations/implications: Results of immersion tests are dependent of used fluid. In this paper used physiological (multielectrolyte) fluid to corrosion studies, which composition is similar to the electrolyte composition of the blood plasma. Chemical composition of fluid used in corrosion studies could be affected to results of studies. Therefore it is appropriate to carry out comparative studies such as electrochemical corrosion studies. Practical implications: Mg-based alloys can be applied as the medical implants. The chemical composition of the samples Mg66Zn30Ca4 and Mg70Zn30 was chosen, because they meet the requirements of a biodegradable material, that is, material, which after completing their stability function will dissolve in the body of the patient without the harmful effects on health. Originality/value: Crystalline and amorphous magnesium alloys are examined as a material for biodegradable medical implants. This new concept is an alternative to previously used conventional implant materials. New concept doesn’t require re-operation, and allows foreign object to remain in the human body.

Fabrication of ternary Ca-Mg-Zn bulk metallic glasses

Nowosielski R., Borowski A., Guwer A., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

2013

Vol. 56, nr 2

67--74

Purpose: The paper describes the preparation, structure and thermal properties of ternary Ca-Mg-Zn bulk metallic glass in form of as-cast rods. Design/methodology/approach: The investigations on the ternary Ca-Mg-Zn glassy rods were conducted by using X-ray diffraction (XRD), scanning electron microscopy (SEM) which energy dispersive X-ray analysis (EDS). Findings: The X-ray diffraction investigations have revealed that the studied as-cast rod was amorphous. The fractures of studied alloy could be classified as mixed fracture with indicated “river” and “smooth” fractures. Both type of the fracture surfaces consist of weakly formed “river” and “shell” patterns and “smooth” regions. The “river” patterns are characteristic for metallic glassy alloys. Practical implications: The studied Ca-based bulk metallic glasses is a relatively new group of material. Ca-based bulk metallic glasses are applied for many applications in different elements. Ca-based bulk metallic glasses have many unique properties such as low density (~2.0 g/cm³), low Youn g’s modulus ( ~20 to 30 GPa). The elastic modulus of Ca-b ased BMGs is comparable to that of hum an bone s, and Ca, Mg, and Zn are biocompatible. These features make the Ca-Mg-Zn–based alloys attractive for use in biomedical applications. Originality/value: Fabrication of amorphous alloy in the form of rod ternary Ca-Mg-Zn alloy by pressure die casting method.