真空蒸馏技术在低熔点金属提纯中的应用

真空蒸馏方法以其流程短、消耗少、对环境无污染等优点,成为高纯金属,特别是低熔点金属的研究热点和工业生产中的最主要的方法之一.综述了真空蒸馏技术在高纯金属提纯方面的现状与前景,详细介绍了真空蒸馏技术的分馏机理和影响因素,包括饱和蒸气压、分离系数和蒸发速率3个方面对真空蒸馏提纯效果和效率的影响.介绍了真空蒸馏技术在高纯金属铋、锑、铟3种低熔点金属制备中的应用,并探讨了采用多种方法联合提纯获得超高纯金属的可行性,通过真空蒸馏与区域熔炼两种方法相结合制备了纯度大于99.999 9 %的超高纯铋.      

ISP工艺流程中金属银的走向与分布

通过对金属银在ISP铅锌冶炼中走向、分布情况的调查及统计分析，提出了提高银回收率的建议．     

还原熔融法测定金属镝中氧含量

研究了用还原熔融法测定金属镝中氧 ,选择合适的仪器工作条件和助熔剂 ,恰当的处理和保存试样 ,以及正确测定空白值和校正仪器 ,取得满意的测定结果。     

基于激光剥蚀-电感耦合等离子体质谱法的金属镝棒统计分布分析初探

高效、高灵敏度的原位微区分析技术开发对于固态电迁移等稀土提纯工艺具有重要意义。实验以固态电迁移提纯后金属镝棒为研究对象,将激光剥蚀-电感耦合等离子体质谱法(LA-ICP-MS)应用于高纯稀土金属的微区分布分析。研究了激光剥蚀速率对样品覆盖率和分析时间的影响,确定了剥蚀速率为50μm/s;考察了剥蚀池及ICP-MS载气流量对待测元素信号强度、氧化物产率及元素分馏效应的影响,确定了载气流量分别为0.60L/min(He)和1.0L/min(Ar)。采用线扫描方式,以基体元素~(158)Dy为内标,获得了不同电迁移区域各杂质元素的二维相对强度分布图,初步探究了各杂质元素的迁移规律。结果显示:在电迁移过程中,Al、Si、Ti、Fe、Mo、W元素从阴极向阳极迁移;Ni、Cu元素从中间区域向两极迁移。这一迁移趋势与辉光放电质谱法(GD-MS)分析结果相一致。同时,LA-ICP-MS还得到更丰富的微区统计分布信息。不同电迁移区域各杂质元素最大偏析度、相对标准偏差(RSD)值及最大偏析位置进一步揭示了各元素的迁移状态,可能与固态电迁移工艺相联系。因此,LA-ICPMS有望为稀土金属提纯工艺解析及优化提供一种新的有效分析手段。     

出钢过程钢水净化工艺优化研究

介绍了转炉在出钢过程强化钢水净化的工艺,实验结果表明:该工艺能在较短时间内降低钢水及熔渣氧化性,利用出钢过程良好的动力学条件进行脱硫,从而提高了LF精炼炉的精炼效果,显著提高了钢水纯净度.通过对工艺的优化和完善,可使部分钢种不经LF炉处理也能满足品种钢性能的要求,进而缓解LF炉作业压力,减少了LF增碳增硅的几率,提高了低碳低硅钢的成分命中率.     

Fiber fragmentation during processing of metallic matrix composites

Fiber fragmentation is a problem frequently encountered during the processing of metallic matrix composites. In this study, we examine the fragmentation of continuous fibers during a common composite consolidation process based on hot pressing in an open-ended channel die with fibers aligned parallel to the die walls. During the latter stages of consolidation, flow of the matrix along the die cavity may occur such that the resulting load transfer to the fibers can cause their fracture even in the absence of bending. This study analyzes the combination of conditions necessary for both matrix flow along the die cavity and the shear-lag loading of the fibers to a level that causes fragmentation. In order to validate the analysis, we model the fragmentation of fibers during elevated temperature hot pressing of Ni-base composites by the room-temperature consolidation of degraded sapphire fibers in a tin matrix. The observed fiber fragmentation behavior is in good agreement with theoretical predictions. The analysis also indicates that this mode of fiber fragmentation is confined either to low volume-fraction fiber composites or to the ends of panels of high volume-fraction fiber composites.     

Recrystallization and texture formation in cold-rolled dysprosium sheet

The primary recrystallization of dysprosium can be characterized by an apparent activation energy of 13.4 ±1.4 kcal/mole when specimens are isothermally annealed at temperatures between 400 and 600°C. At temperatures between 300 and 400°C recrystallization is strongly retarded, possibly by precipitation, and the activation energy associated with the process is increased to 31.4 ±4 kcal/mole. The deformation texture of dysprosium sheet following a cold reduction of 50 pct can be described as (0001)<1010> with a rotational spread of 15 to 20 deg about the rolling direction. Annealing the rolled sheet produces a recrystallization texture which is composed of two components related to the deformation texture by 27 deg rotations about a common 1010 direction. Within the scatter of the data this texture can be represented by the ideal orientation l5l6 (1010).     

金属镝精炼除钙的影响因素

为了降低金属镝中的钙含量,对真空精炼时间,真空度,精炼温度的控制找出了合理的工艺条件,提出了产品质量。