Co-Cr-Mo-W powder obtained by mechanical alloying

ABSTRACT New techniques for manufacturing of biomaterials using additive/substrate manufacturing such as melting laser sintering (SLM) or CAD/CAM milling use micrometric metal powders to build custom parts. CoCrMo alloys are commonly used as biomaterials due to biocompatibility, high corrosion resistance and good mechanical properties. In this work, Cr-Co-based powder was obtained by mechanical alloying of Cr-Co-Mo-W alloy, using different Ball/Powder-Ratios (BPR) and thermal treatments. The powders were deagglomerated and characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Based on SEM micrographs, the particle size analysis was used to compare the particles spheroidizing degree, using Feret’s diameter. The XRD patterns shown Co(solid-solution) as crystalline phase. The results of particles size indicates a decrease of Feret’s diameter in BPR (Ball/Powder-Ratio) from 4:1 to 6:1 understanding that from this ratio there is no significant decrease of this relation but there is an average size increase with losses in morphological aspect. The comparison between atomized powders and powder developed in this work indicates that atomized products present relation close to one which indicates there is uniformity in the particles spherical shape. Comparing ground powders from 6:1 ratio (before and after thermal treatment) there is a considerable decrease of Feret’s diameter being it decreased from 1.75 to 1.4, an increase of about 46% in particles spheroidizing.摘要 采用选择性激光熔化（Selective Laser Melting, SLM）或计算机辅助设计/计算机辅助加工（CAD/CAM）铣削等增材/减材制造工艺制备生物材料的新技术，通常以微米级金属粉末为原料制备定制化构件。钴铬钼（CoCrMo）合金因具备优良的生物相容性、高耐腐蚀性与优异的力学性能，被广泛用作生物材料。本研究通过机械合金化法制备Cr-Co基粉末：以Cr-Co-Mo-W合金为原料，采用不同球料比（Ball/Powder-Ratio, BPR）并结合热处理工艺。对所得粉末进行解团聚处理后，采用X射线衍射（X-ray diffraction, XRD）与扫描电子显微镜（Scanning electron microscopy, SEM）对其进行表征。基于SEM显微图像，采用费雷特直径（Feret’s diameter）开展颗粒尺寸分析，以对比不同样品的颗粒球化程度。XRD图谱结果显示，结晶相为钴固溶体（solid-solution）。颗粒尺寸分析结果表明：当球料比从4:1提升至6:1时，费雷特直径呈下降趋势；当球料比高于6:1时，该尺寸无显著降低，但平均颗粒尺寸出现上升，且颗粒形貌出现劣化。对比雾化粉末与本研究制备的粉末可知，雾化产物的费雷特直径比值接近1，表明其颗粒球形度均匀性更佳。对比球料比为6:1的研磨粉末（热处理前后），可发现费雷特直径显著降低，从1.75降至1.4，颗粒球化程度提升约46%。