应用火花源原子发射光谱法测定了铁素体不锈钢中低含量碳。在经试验优化的方法中提出了以下各要点:① 模铸法取样,按模具高度下端1/3处截取样品,取得样品应无物理缺陷且其表面能不重叠地激发两点;② 选用铣床对样品表面进行加工,并采用固定的仪器参数;③ 分析前用低碳样品先激发一次以清理电极;④ 选择156.1 nm碳谱线作为分析线以避免铝的干扰;⑤ 对样品中高含量铬的干扰,用校正公式作校正;⑥ 为适应低含量碳的测定,制备了一套专用的光谱标样,供制作工作曲线用,其碳质量分数范围为0.003 2%~0.038 3%。按所提出的方法分析了4个低碳铁素体不锈钢样品,所得碳的测定值与高频燃烧红外吸收法的测定结果相符,测定值的相对标准偏差(n=11)均小于8%。

AES with spark light source was applied to the determination of carbon in low contents in ferritic stainless steels. Through optimization of conditions of the method, the following points were emphasized: ① sampling was done by mold-casting, and the portion cut at the lower part of the mold 1/3 along its height was taken as sample which should be free from physical defects and enough for 2 excitation points on its surface without overlapping; ② the surface of the sample should be ground with miller using definite working parameters; ③ before analyzing the sample, a blank test with a low-carbon sample should be done to clear the counter electrode; ④ the carbon spectrum of 156.1 nm was chosen as the analytical spectral line to avoid the interference of aluminum; ⑤ the interference caused by high-contents of chromium was corrected by the correction formula given; ⑥ a set of standard samples covering carbon contents from (w) 0.003 2% to 0.038 3% was prepared for use specially in the preparation of the working curve. Four samples of ferritic stainless steels were analyzed by this method, giving results in consistency with those found by high frequency infrared absorption spectrometry and values of RSD′s (n=11) less than 8%.