电火花-超声复合技术制备镍微米空心球的研究

采用电火花-超声复合技术,以电火花放电过程裂解及超声空化效应所产生的气泡为模板制备微米金属空心镍球,通过扫描电子显微镜、真密度比重仪、振实密度仪、豪斯纳比等对镍微粒在气泡球面的生长过程、镍空心球的成型机理和不同镍空心球的成型原因进行分析和研究,阐述了基于液相基底表面金属薄膜理论的空心球成型过程,并且着重研究超声对颗粒的空心率、微球形貌及微球流动性的影响。结果表明超声的加入使镍空心球的空心率提高10%~20%,改善了颗粒的流动性。

Preparation of Nickel Hollow Microspheres by Ultrasonication-aided Spark Discharge

Based on technology of ultrasonication-aided spark discharge process, the growing process of Ni particles eroded by spark discharge on the bubble surfaces was investigated. The bubbles induced by spark discharge and ultrasonication-induced cavita-tion effect served as templates. The formation mechanism of Ni hollow microspheres by ultrasonication-aided spark discharge was interpreted through analyzing the morphology of samples from SEM. Nitrogen pycnometer density analyzer and tapping density analyzer were used to test the effective and tapping densities of each sample. The effect of ultrasonication on the hollow ratio of Ni particles was studied through comparing the change of effective density on different experimental conditions. The forming process of hollow spheres based on the theory of liquid phase base metal film was expounded. Meanwhile, the effect of ultrasonication on morpho-logy also was investigated through analyzing the values of tapping and losing density. Additional, the Hausner ratio was calculated to explain the liquidity of hollow particles. The results showed that the hollow ratio increase of 10%-20%, and the mobility of the particles was improved by applying ultrasonication.