ČAPEK Jaroslav Institute of Chemical Technology Prague

Recently, magnesium based materials with an interconnected porous structure have been extensively investigated as candidates for the fabrication of biodegradable orthopaedic scaffolds. Powder metallurgy using space-holder materials seems to be a promising method for the preparation of such materials. Microstructure and mechanical properties of the samples can be adjusted by proper selection of initial materials, compaction conditions and sintering conditions. In this paper we focused on the influence of sintering conditions, purity of argon atmosphere and sintering time namely, on microstructural and mechanical characteristics of the prepared samples. An argon of technical purity (99.996 vol.%) and argon purified by a magnesium getter were used as the sintering atmospheres. The samples were sintered for different times (0, 3, 6, 12 and 24 h). Subsequently, microstructure, flexural and compressive behaviour and hardness were investigated in detail. The type of used atmosphere had no significant influence on the studied characteristics after sintering up to 6 h and the mechanical properties increased with longer sintering time. On the other hand, after sintering longer than 6 h, mechanical properties of the samples sintered under the gettered atmosphere increased with longer sintering time, while the use of technical argon decreased mechanical properties significantly and slightly increased porosity. It was caused by oxidation, which took place after longer sintering times under the argon atmosphere of technical purity.