高频燃烧红外吸收法测定硅粉中总碳

采用0.4g锡粒和0.3g纯铁放在坩埚底部,再加入0.150g样品,上面覆盖1.5g钨粒或者使用在坩埚底部加入0.150g样品,上面覆盖1.8g铁钨锡混合助熔剂后进行测定,建立了高频感应燃烧红外吸收法测定硅粉中总碳含量的方法。采用无水碳酸钠标准物质和钢铁标准样品两种物质分别建立了3条碳质量分数为0.001%~0.01%、0.01%~0.10%、0.1%~1.0%的校准曲线。实验表明:校准曲线的线性回归系数均大于0.99;对于同一硅粉样品,采用无水碳酸钠标准物质或钢铁标准样品建立的校准曲线得到的结果是相符合的。采用钢铁标准样品所做校准曲线对NIST57b硅粉标准样品进行测定,测得结果为0.0214%,相对误差为7.0%,符合检测方法确认测定值与真值的相对误差指导范围。组织5家实验室对3个碳含量水平的硅粉样品做方法验证试验,并按照标准方法 GB/T 6379.2-2004对所得结果进行统计检验,结果表明:5家实验室的测定平均值一致性较好,且测得的所有数据均没有离群值,这说明硅粉中碳测定数据的分散性在可接受范围内。加标回收试验表明回收率在95%~120%之间。

Determination of total carbon in silicon powder by high frequency combustion infrared absorption method

0.4 g of tin particles and 0.3 g of pure iron were put on the bottom of crucible, and 0.15 g of sample was added, then they were covered with 1.5 g of tungsten particles for determination. Or 1.50 g of sample was added on the bottom of crucible, and then it was covered with 1.8 g of iron-tungsten-tin mixed flux for determination. Consequently, a method for determination of total carbon in silicon powder by high frequency combustion infrared absorption method was established. Three calibration curves for carbon mass fraction in the range of 0.001%-0.01%, 0.01%-0.10% and 0.1%-1.0% were prepared respectively with the certified reference materials of anhydrous sodium carbonate and steel. The experimental results showed that the linear regression coefficients of calibration curves were all higher than 0.99. For the same silicon powder sample, the determination results which were based on the calibration curve with the certified reference materials whether anhydrous sodium carbonate or steel were consistent. The NIST57b silicon powder certified reference material was determined with the calibration curve prepared by steel certified reference material. The determination result was 0.021 4%. The relative error was 7.0%, which satisfied the guidance range of relative error between the determination result and true value. The verification tests of method were conducted in five laboratories using the silicon powder samples with three carbon content level. The statistics and examination for the results were performed according to GB/T 6379.2-2004. The results indicated that the founds determined by five laboratories were had good consistence, and there were no outliers, indicating that the dispersity of determination results of total carbon in silicon powder was within the acceptable range. The recoveries were between 95% and 120%.