Obtaining of light biocompatible magnesium alloys using levitation equipment under controlled argon atmosphere

Abstract

The use of resorbable materials to make orthopedic implants is a new direction, with major benefits for both the patient and the surgeon. The purpose of a bioresorbable implant is to support the regeneration and healing of tissues, followed by completely dissolving after its purpose is achieved, being characterized by the biodegradability and biocompatibility capability. Magnesium is a natural element of the human body, the magnesium-based implant having the ability to be fully resorbed without inducing local or systemic toxic effects. Experimental alloys were obtained from 99.5% pure magnesium powders in which alloying elements (Ca) or micro-alloying (La, Ce) were added in the 0.5-5% range to identify the best bio-compatible alloy recipes. The metallurgical process was conducted in an induction melting equipment under a controlled atmosphere of argon, through levitation. The melting time for each alloy weighing 15 g was about 3 minutes, and the electrical parameters varied in the range: Voltage Umf = 480 - 500 V; Current Imf = 55 - 65 A; Frequency fmf = 60 - 70 kHz; Power Pmf = 20 - 35 kW. Following the process, about 10% magnesium losses were obtained, due to the vaporization process. The samples obtained were characterized in terms of chemical composition, microstructure and micro-hardness. The micro-hardness values were ranging from 49 to 87.4 HV0.2.