Abstract.Magnesium and its alloy have gained a lot of interest to be used in biomedical application due to its biodegradable and biocompatible properties. In this study, sintering process in powder metallurgy was chosen to fabricatenonporous Mg-6Zn-1Ca (in wt%) alloy and porous Mg-6Zn-1Ca-10Carbamide alloy. For creating porous alloy, carbamide (CO(NH ) was added to alloy system as the space holder to create porous structure material. Effect of the space holder addition and sintering temperature on porosity, phase formation, mechanical properties, and corrosion properties was observed.Sintering process was done in a tube furnace under Argon atmosphere in for 5 hours. The heat treatment was done in two steps; heated up at 250 ºC for 4 hours to decompose spacer particle, followed by heated up at 580 ºC or 630 ºC for 5 hours. The porous structure of the resulted alloys was examined using Scanning Electron Microscope (SEM), while the phase formation was characterized by X-ray diffraction (XRD)analysis. Mechanical properties were examined using compression testing. From this study, increasing sintering temperature up to 630 ºC reduced the mechanical properties of Mg-Zn-Ca alloy.

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This study aims to construct prototypes using three-dimensional (3D) printing technology as a research apparatus and a physics education instrument, particularly in medical physics education. Two main designs of prototypes have been arranged. Two foam NaCl templates are drawn using computer-aided design (CAD) software. Image processing techniques achieve a 3D model of a thoracic vertebra. All 3D model data are printed using polylactic acid (PLA) filament. The prints of foam NaCl templates are utilized for holding the NaCl powder. The prototype of a human vertebra is used for visualization of the real condition of the human bone anatomy. The results of the prototypes are analyzed to investigate the similarity between the model and the prints. This investigation is done using a Vernier Caliper and CT Scan. The measurement using Caliper shows a higher percentage in likeness than the CT-Scan. All the accuracy study shows they have more than 83% in similarity. It can be concluded that all built prototypes have prominent exactitude and can support the material research using the printed NaCl templates. Hereafter, a bone mock-up’s genuine perception can function for further application, such as implant or surgery planning.

Magnesium alloy is a material that has been developed as a biodegradable implant material in orthopedic applications. Magnesium alloys have good biocompatibility, biodegradability, and good mechanical properties which make them have the potential to be used as a biomedical material. The main objective of this paper is to investigate corrotion rate and morphology after corrotion of biocompatibility of implant-based alloys Mg-Ca-Zn with CaCO 3 as a foaming agent. Mg-Ca-Zn Alloy was made by the method of powder metallurgy with the addition of CaCO 3 as a foaming agent with three variations of composition (96Mg-Ca-3Zn-CaCO 3 , 91Mg-Ca-3Zn-5CaCO 3 ,and 86Mg-Ca-3Zn-10 CaCO 3 wt%). Sintering process was carried out at 600 °C and 650 °C with a holding time of five hours. Corrosion test was performed using G750 Gamry Instrument in accordance with ASTM standard G5-94. Simulated body fluid electrolyte used is Hank's solution with a pH value of 7.4 and a temperature of 37 °C. Then the analysis of the microstructure after corrosion test was conducted using scanning electron microscopy (JEOL, JSM-6390A Japan) equipped with energy dispersive spectrometry data (EDS). Alloy corrosion rate of Mg-Ca-Zn-CaCO 3 increases with the amount of CaCO 3 in the alloy and the temperature rise in the sintering. From the test results, the smallest corrosion rate is in the alloy 91Mg-Ca-3Zn-CaCO 3 at 600 °C sintering (58.3045 mpy) and the highest occurs in alloy 86Mg-Ca-3Zn-10CaCO 3 at 650 °C sintering (91.4007 mpy). Surface morphology of the alloy after the corrosion process is the type of volcano. This localized corrosion occurs where an electrochemical reaction takes place to form a distinctive structure with a circle and a hole in the middle.

Graphene oxide and reduced graphene oxide attract a lot of attention due to graphene provides some properties that suitable for wider application. Properties of graphene are unique since it can be tuned regarding to its controlled synthesis method and several treatments. This work, graphene oxide was synthesized from used graphite electrode by modified Hummer’s method in which oxidation process controlled. Zinc was used to produce reduced graphene oxide. Graphene oxide and reduced graphene oxide were characterized by SEM, EDS, FT-IR, UV-vis, and XRD. Effective strategy was studied to produce graphene oxide and reduced graphene oxide by controlling its oxidation process. These results prove that chemical and structural properties of graphene oxide and reduced graphene oxide depend on oxidation duration. Furthermore, carbon/oxygen ratio was studied to evaluate effective oxidation process.