火花放电原子发射光谱法测定铁基纳米晶合金中氮

为了在铁基纳米晶合金生产过程中进行氮的质量控制分析,提出了用火花放电原子发射光谱法测定铁基纳米晶合金中氮含量的方法。对测定氮的光谱线选择、氮的分析条件、内控标样的制作、取样方法的验证、分析样品的分取和处理、共存元素的干扰影响和氮校准曲线的拟合等问题进行了讨论。确定测定氮的最佳分析条件如下:高纯氩气(φ≥99.999%)流量为180L/h,氩气冲洗时间为2s,预燃(HEPS)时间为6s,积分时间为2s,分析线对为N149.3nm/Fe149.7nm。在上述分析条件下,采用自制的含氮铁基纳米晶合金标准样品绘制了氮的校准曲线并校正了共存元素的干扰。采用实验方法测定了铁基纳米晶合金分析样品中氮的含量,其测定结果的相对标准偏差(RSD,n=8)小于7.0%,所得的分析结果与用脉冲加热-热导法的测定值一致。实验方法也可实现铁基纳米晶合金分析样品中氮和合金元素含量的同时测定。

Determination of nitrogen in Fe-base nanocrystal alloy by spark discharge atomic emission spectrometry

In order to carry out the quality control analysis of nitrogen in production process of Fe-base nanocrystal alloy, the determination method of nitrogen in Fe-base nanocrystal alloy by spark discharge atomic emission spectrometry was proposed. Some questions in the determination of nitrogen were discussed, including the selection of spectral lines, the analytical conditions of nitrogen, the preparation of standard samples for internal control, the verification of sampling method, the division and treatment of analytical samples, the effects of interference by coexisting elements, and the fitting of calibration curve. The optimum analysis conditions for the determination of nitrogen were listed as below: the flow rate of high-purity argon (φ≥99.999%) was 180L/h, the flush time of argon was 2s, the precombustion (HEPS) time was 6s, the integral time was 2s, and the analytical line pair was N149.3nm/Fe149.7nm. Under the analytical conditions above, the calibration curve of nitrogen was prepared using the self-made standard sample of nitrogen-containing Fe-base nanocrystal alloy. Moreover, the effects of interference for coexisting elements were corrected. The content of nitrogen in Fe-base nanocrystal alloy sample was determined according to the experimental method. The standard deviation (RSD, n=8) of measured results was less than 7.0%. The found results were consistent with those obtained by impulse heating-thermal conductivity method. The proposed method was also applicable for the simultaneous determination of nitrogen and alloying elements in Fe-base nanocrystal alloy samples.