Determination of the crystallite size and crystal structure of magnesium powder by x-ray diffraction

Magnesium powder has become an important material in the development of science and technology such as alloy and hydrogen storage. In this work, the chemical composition, crystallite size, and crystal structure of the magnesium powder sample have been studied by using x-ray fluorescent and x-ray diffraction. The x-ray diffraction data of the magnesium powder sample was analyzed by using the Rietveld method to obtain the crystal structure. Our results show that the purity of our magnesium powder sample is 93.1%. Our sample has good crystallinity with the average crystallite size of 31 nm. The crystal structure is found to be a hexagonal closed-packed structure with the lattice constants of 3.2100 Å (a and b-axis) and 5.2107 Å (c-axis). Our result revealed that the lattice constant in the c-axis of magnesium powder is influenced by impurity. This finding suggests that the impurity can affect the crystal structure of a material in general.

An Experimental Analysis of Composite Nursing Material of Degradable Magnesium/Polylactic Acid in the Treatment of Postoperative Pain After Orthopedic Surgery

In this study, magnesium is used as the modified material of polylactic acid (PLA). In the process of combining magnesium and PLA, the magnesium powder is pre-treated with fluorine conversion, that is, the surface of the magnesium powder would form a fluoride membrane, and then it is compounded with PLA to form Mg-F-PA. In the experiment, the morphology of the material is analyzed first. Magnesium powder and magnesium fluoride powder are evenly dispersed on the surface of the composite material, and the surface of the composite material is relatively flat. At the same time, it is found in the mechanical analysis that the mechanical strength of composite Mg-F-PA decreases compared with that of single PLA, but the binding force of magnesium fluoride powder + PLA is stronger than that of magnesium powder + PLA. 120 patients with lower extremity fractures of ASA I∼III are selected and divided into 4 groups, with 30 cases in each group. These patients are treated with hip replacement (group 1), artificial femoral head replacement (group 2), open reduction and internal fixation for lower limb fractures (group 3), open reduction and internal fixation for lower limb fractures + Mg-F-PA (group 4). Then, postoperative evaluation is conducted. The clinical results show that the group 4 is better than the other 3 groups in terms of the sedation degree score, the number of pain pump presses and the incidence of postoperative adverse reactions (P < 0.05). Therefore, the orthopedic material that proposed in this study can reduce postoperative pain.

Assessment of Applicability of the MPF-4 Magnesium Powder for Manufacturing Parts Using 3D Printing Technologies

The article provides study results for two samples manufactured with the MPF-4 magnesium powder by means of directed laser energy and material deposition. The authors studied microhardness and microstructure of the samples by means of optical and electronic microscopic techniques; provided results of the impact of annealing on microstructure and microhardness of the samples; and assessed the possibility of using the MPF-4 powder for manufacturing parts using 3D printing technologies.