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采用硫化氢分离、深孔电极直流电弧粉末法进行了一种镍基合金中微量有害杂质(Pb,Bi,Sn,Sb,As)的分析。由于操作流程较长,试剂用量亦较大,即使采用分析纯级试剂实验空白(主要为Pb,Sn,As)也很高。为此系统地分析了空白的来源,并寻找了降低的办法,最后使Pb,Sn的空自值降低至1—2微克。满足了分析的要求。试样中,As的蒸发很不完全。加入P_2O_5后,使As的蒸发大大加速。由于有效地利用了样品,因而使As的灵敏度提高了4—5倍。实验中发现在As 2349埃处有碳电极在空气中燃弧所产生的带状光谱。系统实验的结果表明,可以用经过硫化氢沉淀后的纯溶液来配制标准样品,避免了采用一般增量法制定定标曲线,保证了结果的准确度。通过系统实验,确定了操作条件。对于三个实际试样进行了多次分析。结果说明,本法的分析下限分别为:Pb:0.0001%,Sn,Sb:0.0002%,As:0.0003%,Bi:0.00002%。
A series of nickel-based alloys were analyzed for their harmful impurities (Pb, Bi, Sn, Sb, As) by hydrogen sulfide separation and deep-hole electrode DC arc powder method. Due to the long operation process and large amount of reagents, experimental blank (mainly Pb, Sn, As) is very high even with analytical grade reagent. To do this, we systematically analyzed the source of the blank and looked for a way to reduce it. Finally, the empty values of Pb and Sn were reduced to 1-2 μg. Meet the analysis requirements. In the sample, As evaporation is incomplete. After adding P_2O_5, the evaporation of As accelerates greatly. As a result of effective use of the sample, thus increasing the sensitivity of As 4-5 times. In the experiment, it was found that there was a banded spectrum produced by arcing carbon electrodes in air at As 2349 A. The results of the system experiment show that the standard sample can be prepared by pure solution after being precipitated by hydrogen sulphide, which avoids using the standard increment curve to establish the calibration curve and ensures the accuracy of the result. Through systematic experiments, the operating conditions were determined. Multiple analyzes were performed on three actual specimens. The results show that the lower limits of analysis of this method are: Pb: 0.0001%, Sn, Sb: 0.0002%, As: 0.0003%, Bi: 0.00002%.