等离子旋转电极雾化法制备钛核壳粉末工艺研究

Study on the Plasma Rotating Electrode Atomization Technique for Core-Shell Powder Synthesis

摘要:

通过对现有的等离子旋转电极雾化（plasma rotating electrode atomization，PREP）制粉设备进行改进，在用纯钛棒料制粉过程中调节不同氮气通入流量，制备出内部为低氮量表层为高氮量的核壳结构粉末。利用标准振筛机、激光粒度分析仪、X射线衍射（XRD）、扫描电镜（SEM）、X射线光电子能谱（XPS）对粉末粒度分布、微观形貌、组织结构等进行表征。结果表明：通入氮气后的粉末粒径比不通氮气的粉末粒径要小，当通入氮气流量由3 L/min增加到8 L/min时，粉末粒径呈现先减小后增大的变化趋势。通入氮气可以有效地抑制纯钛金属粉末中卫星粉的形成，同时改善球形粉末的表面形貌使其变得光滑，但是也会使粉末中出现长条状和球化不充分的异形粉末颗粒。在不同氮气流量下所制备的粉末表面都均匀分布N元素，形成了Ti-N_x组织的壳层，粉末表层的氮含量明显高于内部。

Abstract:

By modifying the existing plasma rotating electrode atomization (PREP) powder production equipment, the core-shell structure powders with low nitrogen content in the core and high nitrogen content on the surface were successfully prepared by adjusting the nitrogen flow rate during the powder-making process with pure titanium rods. The particle size distribution, microscopic morphology, and microstructure of the powders were systematically characterized using a standard vibrating sieve, laser particle size analyzer, X-ray diffractometer (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscope (XPS). The results show that the particle size of the powders with nitrogen gas were smaller than that without nitrogen gas. As the nitrogen flow rate increases from 3 L/min to 8 L/min, the particle size exhibits a trend of first decreasing and then increasing. Introducing nitrogen gas can significantly suppress the formation of satellite powders in pure titanium metal powders and make the surface of the powders smooth, but it can also result in elongated and insufficiently spheroidized shaped powder particles in the powder. Under different nitrogen gas flow rates, nitrogen is uniformly distributed on the powder surface, forming a Ti-N_x microstructures shell layer, and the nitrogen content on the powder surface layer is significantly higher than that in the core.