Journal of Materials Science and Engineering A 5 (1-2) (2015) 21-36 doi: 10.17265/2161-6213/2015.1-2.003 Bioactivity Investigations with Calcia Magnesia Based Composites Emad Mohamed Mohamed Ewais 1* , Amira Moustafa 1 , Karoline Pardun 2 and Kurosch Rezwan 2 1. Refractory & Ceramic Materials Division, Advanced Materials Department, Central Metallurgical R&D Institute, Cairo 11421, Egypt 2. Advanced Ceramics, University of Bremen, Bremen 28359, Germany Abstract: The bioactivity and physico-mechanical properties of calcia magnesia based composites developed in this study were investigated. Different composite mixtures containing calcia-magnesia have been processed with the addition of alumina, silica or zircon. These system powders were formed and fired at two different temperatures. The produced composites were characterized by means of X-ray diffraction, SEM (scanning electron microscope) equipped with EDS (energy dispersive X-ray spectrometry), density and apparent porosity measurements, mechanical testing and in-vitro evaluation in a SBF (simulated body fluid) solution. The compositions termed “I”, “II” and “III” gave clear tendency towards the formation-ability of HA (hydroxyapatite). Composite “1” gave cubic and spindle HA crystallite, while composites “II” and “III” fired at 1,300 and 1,400 °C formed typically “cauliflower” morphology and their evaluated physico-mechanical properties are similar to the properties of human cortical bone. Thus, composites “II” and “III” might be a promising bone implant materials. Beside the bioactivitiy of composite “I”, it also contains highly CA (cementing phase) and MA (bioinert) phases, therefore, it might be nominated as a promising bioceramic material especially for different purposes such as scaffold, bone replacement, bone repair and coating. Key words: Calcia-magnesia, zircon, alumina, SBF, bending strength. 1. Introduction Bioceramics are engineered materials that find applications in the field of medicine [1]. This class of materials, particularly the bioactive one, has become one of the major fields in biomaterials over the last three decades due to its attractive feature for bone repair such as direct bone-bonding in the body. The essential condition of artificial materials to show bioactivity is the formation of bone-like apatite on their surfaces in body environment. The brittleness, low fracture toughness and low impact resistance of the bioceramics have limited their applications. Nevertheless, at the end of the sixties, a strong interest in the use of ceramics for biomedical engineering applications was developed. Since then, further improvements in ceramic properties have been made Corresponding author: Emad Mohamed Mohamed Ewais, Professor, Dr., research fields: refractories and ceramics. E-mail: dr_ewais@hotmail.com. and opened the wide span of their biomedical applications [2, 3]. When bioactive materials are implanted into the human body, they interact with the surrounding bones or other tissue to some extent. An ion-exchange reaction between the bioactive implant and surrounding body fluids results in the formation of a biologically active carbonate-containing hydroxyapatite layer on the implant that is chemically and crystallographically equivalent to the mineral phase in the bone, which promotes the bonding between the natural tissues and the material. Like other bioactive materials, bioactive ceramics can directly bond to the living bone tissue. Sintered HA (hydroxyapatite) has been recorded a remarkable success as implant materials in the clinical use due to its bioactivity and osteoconductivity [4-7]. However, the low fracture toughness of HA ceramic limit the scope of clinical applications [8, 9]. D DAVID PUBLISHING