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Mg-Ca-Zn alloys are promising candidate metal cellular material for biocompatible and biodegradable implant. This is due to its corrosion behavior which enables well controlled degradation, as well as due to the fact that the corrosion product shows no cytotoxicity at all. In this present work, the characteristics of Mg-Ca-Zn alloy metallic foam prepared by the foaming of a powder compact based on Mg-2Zn-Ca and CaH2 system were investigated. Mg-Zn-CaH2 powders with various compositions of 67-96 wt.% Mg, 1.2-30 wt.% CaH2, 9 wt.% Ca and 2 wt.% Zn constant were studied. The prepared powders were then pressed under a load of 26 MPa at room temperature. Sintering process of green compacts was conducted at 350 °C for 2 h continued to 520 °C for 1 h. The sintered green compacts were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis (EDS). The XRD results showed the sintering process affects the phase formation of Mg, Ca, Mg2Ca, and MgCaZn. Mg2Ca binary phase to be avoided because its leading to reduce mechanical properties of the final product.

The synthesis and characterization of both structural and microstructure of hydroxyapatite (HAp) nanoparticles by using precipitation method have been performed. Orthophosphoric acid solution (H3PO4) 0.3 M was dropped into the suspension of Ca(OH)2 from tutut (Bellamya javanica) shells at pH 10 and added by NH4OH 1 M at the final deposition process. The precipitate was filtered and then heated in a furnace at temperature of 1000 °C for 3 hours. The result of elemental analysis showed that the Ca/P ratio of HAp sample was 1.71. X-ray diffraction patterns showed that the sample was a single phase of Ca10(PO4)6(OH)2 with hexagonal structure (P63/m) and lattice parameters of a = b = 9.418(3) Å, c = 6.885(2) Å, a = b = 90o, g = 120o, V = 528.9(4) Å3, and r = 3.084 g cm-3. The as-synthesized HAp has crystallite and particle sizes of 16.1055 and 89.15 nm, respectively. The TEM image revealed that the HAp particles have spherical-polygonal shape with an average diameter particles of around 10-20 nm. It was concluded that the synthesis of HAp nanoparticles from tutut (Bellamya javanica) shells by using a wet precipitation method has been successfully carried out and the as-synthesized HAp was potential to be applied as materials for artificial bone engineering.