关于仪器分析用标准样品均匀性初检的探讨

仪器分析用标准样品中存在的成分不均匀主要是由铸造过程中形成的宏观偏析造成的,预测铸锭中可能存在的宏观偏析,是标准样品均匀性初检的前提和基础。在分析和讨论均匀性初检基本概念的基础上,按铸造、成形工艺将仪器分析用标准样品分成4类:铸锭-锻轧型、连铸-锻轧型、多支铸锭型和多支铸锭-切割型。在凝固过程中溶质原子再分配理论的指导下,对不同铸造工艺形成的宏观偏析特点进行了分析、研究,提出了均匀性初检应重点关注的偏析类型,为制定均匀性初检取样方案提供了依据。

Discussion on the initial homogeneity inspection of certified reference materials/samples for instrumental analysis

The composition inhomogeneity of certified reference materials/samples for instrumental analysis was mainly caused by macrosegregation in casting process. The prediction of possible macrosegregation in cast ingot was the precondition and foundation for the initial homogeneity inspection of certified reference materials/samples. Based on the analysis and discussion on basic conception of initial homogeneity inspection, the certified reference materials/samples for instrumental analysis were classified into four types according to casting and formation processes, i.e., cast ingot-forging rolling type, continuous casting-forging rolling type, multi-cast ingots type and multi-cast ingots cutting type. Under the guidance of redistribution theory of solute atoms in solidification process, the macrosegregation characteristics formed in various casting processes were analyzed and investigated. The segregation types which should be paid attention in initial homogeneity inspection were proposed. The study provided the basis for making sampling plan in initial homogeneity inspection.