Determination of Trace Metals in High-purity Silicon Nitride Powder by Solution. cathode Glow Discharge-atomic Emission Spectrometer Using Slurry Sampling

Trace impurities of Al, Ca, Co, Fe, K, Mg, Mn, Na, Ni in silicon nitride powder were determined by slurry introduction into a solution. cathode glow discharge. atomic emission spectrometer (SCGD-AES). The effect of particle size on the stability of suspension was investigated. A 6-port valve was selected to link sampling system and SCGD-AES, by which the suspension could be introduced into the SCGD-AES to get instantaneous spectrum signal. The calibration curves for quantitative analysis could be established using aqueous standards and the pH of suspension was not required to be adjusted accurately. The applied voltage, solution flow rate, and integral time of PMT were set to 1080 V, 1.2 mL/min and 800 ms, respectively. In this work, slurry sampling was combined with SCGD-AES by a 6 port 2-pos valve. Powder Si3N4 was tested by this way and the limits of detection for all nine elements were 0.2-53.0 mg/kg. The RSDs were 1.1% - 5.0%. The detection result of trace impurities in standard reference material ERM-ED101 agreed with that obtained from inductively coupled plasma atomic emission spectrometry. This method was proved to be accurate, reliable and valuable.