用硝酸及少量氢氟酸可将试样完全溶解,所得溶液可用于电感耦合等离子体原子发射光谱法(ICP-AES)或钼蓝分光光度法测定镁和镁合金中的硅含量,对ICP-AES测定硅的分析条件作了试验.为避免各共存元素的干扰,方法中选择波长为SiⅠ 251.611 nm及SiⅠ 212.412 nm的谱线作为分析谱线.在制作工作曲线时加入与待测样品等量的镁以补偿基体组分引起的基体效应,在选用上述两谱线作为分析线时,硅的质量浓度在40.0 mg·L-1以内时与谱线的发射强度均呈线性关系,所得检出限(3S/N)依次为6.2和15 μg·L-1.应用此方法分析了3种镁合金标准样品,所得结果与标准值相符.

Samples of magnesium and its alloys were completely dissolved by addition of dil.HNO3 and small amount of HF,and the sample solution obtained was used for determination of silicon by ICP-AES or molybdenum blue-spectrophotometric method.Conditions for ICP-AES determination of silicon were studied and optimized.To avoid the interferences of co-existing ions,spectral lines of SiⅠ 251.611 nm and SiⅠ 212.412 nm were chosen as the analytical lines.The interference of matrix effect due to magnesium was eliminated by addition of appropriate amounts of magnesium to each portion of standard silicon solutions in preparation of calibration curve.Linear relationships between values of the spectral emission intensity and mass concentration of silicon were kept in the range within 40.0 mg·L-1 for using either of the 2 analytical spectral lines,and the detection limits (3S/N) of 6.2 μg·L-1 and 15 μg·L-1 were obtained when determined with the 2 analytical spectral lines respectively.Three standard samples of magnesion alloys were analyzed by the proposed method,giving results in consistency with the standard values.