材料期刊网

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50 μm/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0.60 L/min(He)和1.0 L/min(Ar).采用线扫描方式,以基体元素158Dy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-ICP-MS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.

The development of high-efficiency and high-sensitivity in situ microanalysis technology for rare earth purification process, such as solid state electromigration, is of great significance.The dysprosium rods after purification by solid state electrotransport were investigated.The laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied for the micro-area distribution analysis of high-purity rare-earth metals.The effect of laser ablation rate on sample surface coverage and analysis time was studied.The optimized ablation rate was 50 μm/s.Moreover, the influence of ablation cell and ICP-MS carrier gas flow on the elemental signal intensity, oxide yield and elemental fractionation effect was also investigated.The optimized carrier gas flow was 0.60 L/min (He) and 1.0 L/min (Ar).By using 158Dy as the internal standard, the two-dimensional relative intensity distribution of various impurity elements in different electromigration areas was obtained in line scanning mode.The migration patterns of impurity elements were preliminarily explored.The results showed that Al, Si, Ti, Fe, Mo and W migrated from cathode to anode in electromigration process, while Ni and Cu migrated from the mid-region towards two poles, which was consistent with results obtained by glow discharge mass spectrometry (GD-MS).In addition, more abundant micro-area statistical distribution information could be obtained by LA-ICP-MS.The maximum segregation degree, relative standard deviation (RSD) and maximum segregation position of impurity elements in different electromigration regions revealed that the migration status of elements was possibly related to the process of solid state electromigration.Therefore, LA-ICP-MS perhaps provided a new and effective tool for the process analysis and optimization of purification of rare-earth metals.