电感耦合等离子体原子发射光谱法分析复杂高温合金中痕量硅的干扰及校正方法探讨

高温合金中硅含量的高低影响材料的物理和化学性能,准确测定高温合金中硅是对材料进行质量控制的重要保证。而使用电感耦合等离子体原子发射光谱法(ICP-AES)测定高温合金中痕量硅时存在明显的基体效应和复杂的光谱干扰。采用盐酸-硝酸混合酸和氢氟酸溶解样品,采用基体匹配法配制标准溶液系列消除基体效应的影响,选择Si 184.685nm、Si 185.005nm、Si 251.611nm作为分析线,利用硅与氢氟酸形成挥发性物质的特性,以及硅受钽、钼、铼、钨等合金元素干扰的特点,使用干扰等效浓度(IEC)法和基体空白差减法对测定结果进行校正,建立了使用ICP-AES测定复杂高温合金中痕量硅的分析及干扰校正方法。硅的质量分数在0.005%~0.40%范围内校准曲线呈线性,线性相关系数r达0.9999;方法中硅的检出限小于0.001%。方法应用于高温合金样品中硅的测定,结果的相对标准偏差(RSD,n=7)小于2%;采用两种校正方法的结果与辉光放电质谱法(GD-MS)的结果进行比对,一致性较好。

Discussion on interference and correction method during the analysis of trace silicon in complex superalloy by inductively coupled plasma atomic emission spectrometry

The physical and chemical properties of superalloy materials are affected by the content of silicon. The accurate determination of silicon in superalloy is an important guarantee for quality control. Obvious matrix effect and complex spectral interference exist during the determination of trace silicon in superalloy by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sample was dissolved with hydrochloric acid-nitric acid mixture and hydrofluoric acid. The matrix effect was eliminated through preparing standard solution series by matrix matching method. Si 184.685nm, Si 185.005nm and Si 251.611nm were selected as the analytical lines. According to the characteristic that silicon could form volatile substances with hydrofluoric acid and silicon was easily interfered by alloying elements such as tantalum, molybdenum, rhenium and tungsten, the determination results were corrected by interference equivalent concentration (IEC) method and matrix blank subtraction method. The analysis and interference correction methods of trace silicon in complex superalloy by ICP-AES were established. The calibration curve was linear when the mass fraction of silicon was in range of 0.005%-0.40%, and the linear correlation coefficient (r) was 0.9999. The detection limit was less than 0.001%. The proposed method was applied for the determination of silicon in superalloy samples. The relative standard deviation (RSD, n=7) of results was less than 2%. The found results using two types of correction methods were compared with those obtained by glow discharge mass spectrometry (GD-MS), and the consistency was good.