滴定法测定镍基合金中铁量的不确定度评定

Evaluation of uncertainty for the determination of iron in nickel base alloys by titration method

对三氯化钛-重铬酸钾滴定法测定镍基合金中铁量的不确定度产生原因进行了分析,对测量过程中的主要不确定度分量进行了评定,包括重铬酸钾标准溶液浓度带来的不确定度,滴定试样体积和滴定空白体积带来的不确定度,称重带来的不确定度和试验总重复性带来的不确定度。估算了各分量的大小,分析对结果影响相对大的分量为方法确认时的重复性以及滴定时重铬酸钾消耗体积的不确定度分量。

The causes of uncertainty for the determination of iron in nickel base alloys by titration method was analyzed, and the main uncertainty component in the determination were evaluated, such as the uncertainties caused by the concentration of K2Cr2O7 standard solution, the volume of titration with sample and blank, the weighing of sample and the repeatability of the method. Through estimating the weight of each uncertainty component, it could be conclude that the uncertainties arising from the repeatability of the method and the consumed volume of the potassium dichromate in titration have the relative bigger effect on the determination results.