Cobalt based alloys were the first metallic materials successfully used in orthopedic applications. However, these alloys are bio-inert, it is necessary to make them bioactive in the human body to improve their application as biomaterials. This research reported the microstructure and in-vitro bioactivity behavior of the novel Co-Cr-Mo alloy (ASTM F-75) filled with different amounts of hydroxyapatite (HAP). F-75 powder was mixed with 2, 6 and 10 wt. % of HAP before being cold compacted at 550 MPa using a uni-axial press machine. The composites then were sintered at 1100°C for 2 h. In-vitro bioactivity behavior of the composites was evaluated by immersing the composites into simulated body fluids for up to 18 days. Results showed that the nucleus of apatite, identified as the apatite layer formed on the surface of the prepared F-75/HAP composite after 18 days of immersion in the phosphate buffered solution (PBS). The Co-Cr-Mo alloy was successfully converted into a bioactive composite by adding 2, 6 and 10 wt. % of HAP particles. It was proposed that the formation of the apatite layer on the surface of F-75/HAP can contribute to the improved biocompatibility and osteoconductivity of F-75/HAP.
Recently, many researchers focused on biocompability, corrosion resistance and properties behavior of implant materials in order to length the endoprostheses life. One of the rapid development areas of research is in the biomaterials field. Historically the uses of biomaterials has been to replace diseased or damaged tissues. This present paper reviews the research works carried out in the field of composite metal alloys reinforced with additive and to analyze the influence of modifying additive on mechanical properties of composite materials on the cobalt (Co), titanium (Ti) and magnesium (Mg) based alloy. The desirable mechanical properties of the matrix component compensate for the poor mechanical behavior of the biomaterials, while in turn the desirable bioactive properties of the additives improve those of metal alloys. The following additives were reviewed for research: poly methyl methacrylate (PMMA), fluoroapatite (FA) and bioglass. Results show that these composites can be the alternative materials for biomedical applications.
AZ series alloy which consist of aluminium (Al) and zinc (Zn) with magnesium (Mg) as their base are the most investigated for biomedical applications among the Mg alloy. Al content plays a crucial part in differentiating the properties of Mg-based alloy for biomedical applications. Thus, this project picks up pure Mg and AZ31 (with 3% of Al) alloy and the effect of Al content has been investigated. In this study, Mg alloy has been fabricated via powder metallurgy method in order to investigate its bioactivity behaviour. Bioactivity test of pure Mg and AZ31 alloys were conducted by immersing the samples in simulated body fluid (SBF) solution up to 6 hours to observe the formation of apatite layer on the sample surface. The bioactivity behaviour of the samples has been observed using scanning electron microscope (SEM) and X-Ray Diffraction (XRD) analysis. After bioactivity test, sample AZ31 showed the formation of more apatite layers compared to sample of pure Mg with the existence of new phases which were Mg(OH)2 and MgO. This apatite layers might influence the ability of the Mg-based alloy to withstand the corrosive agent that will attack the alloy while being immersed in SBF.
This study focuses on the synthesis of synthetic calcium monosilicate ceramic from chicken eggshells and rice husks waste through the mechanochemical route that relatively straightforward without adding any binders. Synthetic calcium monosilicate was mixed using a 1:1 ratio of calcined eggshell and rice husk ash, which both materials known as rich in calcium oxide and silica sources, respectively. The mixed powder was pressed using uniaxial pressing before fired at 1100°C, 1150°C, 1200°C, 1250°C, and 1300°C for 120 minutes with a heating rate of 5°C/min. The XRD spectrum from 1100°C to 1200°C mainly consists of pseudowollastonite (ICSD: 98-005-2576), wollastonite and silicon dioxide phases. However, as the sintering temperature increases, the wollastonite phases was completely transformed into pseudowollastonite, leaving some unreacted silica.
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