微波消解-火焰原子吸收光谱法测定氮化铝粉中钾和钠

氮化铝粉体中钾、钠杂质含量对氮化铝陶瓷制品的热导率有重要影响。常温常压下氮化铝无法溶解,而碱熔法不适用于钾、钠的分析。实验以盐酸辅助微波消解分解氮化铝样品,并采用火焰原子吸收光谱法(FAAS)分别于波长766.5nm和589.0nm处测定钾、钠含量,建立了微波消解-火焰原子吸收光谱法测定氮化铝粉中钾和钠的方法。实验研究了铝基体及共存元素对钾、钠测定的影响,优化了微波消解条件、酸度以及消电离剂的加入量。钾、钠校准曲线线性相关系数分别为0.9999和1.000,钾、钠特征浓度分别为0.026μg/mL和0.015μg/mL,钾、钠的检出限分别为0.7μg/g和0.5μg/g。按照实验方法测定氮化铝样品中钾、钠,结果的相对标准偏差(RSD,n=7)均小于4%;加标回收率分别为103%和98%;结果与电感耦合等离子体原子发射光谱法(ICP-AES)分析结果相吻合。方法以高纯铝进行基体匹配有效地解决了基体效应对测定的影响,适用于纯度大于99.9%的氮化铝粉中钾、钠的分析。

Determination of potassium and sodium in aluminum nitride powder by microwave digestion-flame atomic absorption spectrometry

The contents of potassium and sodium impurities in aluminum nitride powder had an important effect on the thermal conductivity of aluminum nitride ceramic products. Aluminum nitride could not be dissolved under normal temperature and pressure, and the alkali fusion method was not suitable for the analysis of potassium and sodium. The aluminum nitride samples were decomposed with hydrochloric acid by microwave digestion in experiments. Then the contents of potassium and sodium were determined by flame atomic absorption spectrometry (FAAS) at 766.5nm and 589.0nm, respectively. The determination method of potassium and sodium in aluminum nitride powder by microwave digestion-flame atomic absorption spectrometry was established. The effects of aluminum matrix and coexisting elements on the determination of potassium and sodium were studied. The microwave digestion conditions, acidity and the dosage of deionizer were optimized. The linear correlation coefficient of calibration curve for potassium and sodium was 0.9999 and 1.000, respectively. The characteristic concentration was 0.026μg/mL for potassium and 0.015μg/mL for sodium, respectively. The limit of detection was 0.7μg/g and 0.5μg/g for potassium and sodium, respectively. The contents of potassium and sodium in aluminum nitride powder sample were determined according to the experimental method. The relative standard deviations (RSD, n=7) of potassium and sodium were both less than 4%. The spiked recovery was 103% and 98%, respectively. The found results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES). The influence of matrix effect on the determination was effectively solved by matrix matching with high purity aluminum. The proposed method was applicable for the analysis of potassium and sodium in aluminum nitride powder with purity higher than 99.9%.