SiC超细粉的化学分析(Ⅰ)──示差分光光度法测定SiC超细粉末中的总硅量

Determination of the Total Silicon Content in Ultrafine SiC Powders by Differential Spectrophotometry

在碳化硅的总硅量测定中，样品的分解是其关键之一。本文采用NaOH和Na2O2（2：1）的混合溶剂，在银坩埚中于700℃下熔融20分钟来分解SiC超细粉末。由于SiC中的总硅量高达70％左右，所以用500μg／100ml的标准SiO2溶液作为参比溶液，以硅钼蓝示差分光光度法测定SiC超细粉末中的总硅量。本方法的最大吸收波长λ=800nm，在该波长处的表观摩尔吸光系数ε=2．51×104。

The decomposition of samples is one of the key steps in determining the total silicon content in SiC.We have used NaOH and Na2O2 (2:1) as a fusing mixture and used a siliver crucible as our container to decompose ultrafine SiC powders at 700℃ for 20 minutes. Because the total silicon content in SiC amounts is about to 70%, We have taken a standard solution containing SiO2500μ/100ml as a reference solution to determine the total Si content in SiC by differential spectrophotometry of silicon - molybdenum blue. The maximum absorption wavelength(λ) in this method is 800nm and the apparent molar absorptivity (ε) at this wavelength is 2. 51 ×104.