Direct analysis of silicon carbide by fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry using a slurry sampling technique

Abstract

Slurry sampling in combination with fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) was employed for the direct determination of trace impurities in silicon carbide ceramic powders. The vaporization behaviors of silicon and five trace elements (Al, Cr, Cu, Fe and V) were studied in the presence and absence of polytetrafluoroethylene (PTFE) as fluorinating reagent. It was found that, during a 60 s ashing step at 800 °C, about 97% of 100 μg of SiC can be decomposed and evaporated without considerable losses of the trace elements investigated. Calibration was performed using the standard addition method and the calibration curve method, applying spiked slurries and aqueous standard solutions, respectively. The accuracy was checked by comparison of the results with those obtained by solution fluorination assisted ETV-ICP-AES and pneumatic nebulization (PN)-ICP-AES involving wet chemical decomposition of the sample. Detection limits between 0.3 μg g⁻¹ (Al) and 0.08 μg g⁻¹ (Cu) were achieved. The precision, expressed as the relative standard deviation (RSD), was between 6.0% (for 18.2 μg g⁻¹ of Cr) and 2.8% (for 177 μg g⁻¹ of Fe).