以硝酸和磷酸(V(HNO3)∶V(H3PO4)=5∶1)作为消解试剂,采取高压密闭微波加热方法对钨钴或钨镍类钨基硬质合金样品进行消解,消解液用水定容后直接以电感耦合等离子体原子发射光谱法(ICP-AES)测定0.005％～10％ Co、Ni和0.005％～1％ Fe、Nb、Ta、V、Cr、Mo的含量.考察了消解试剂中的硝酸和磷酸量对试样消解的影响以及微波控制参数等最佳消解条件,建立了微波消解-无机试剂络合基体钨的样品消解方法,从而避免了因钨酸沉淀析出而导致部分待测元素损失和使用有机络合剂对光谱测定的干扰影响.实验结果表明:采用以5 min升温至130℃并保持5 min,再以5 min升温至190℃并保持15 min的消解程序,样品的消解效果较好.试验通过优选元素分析谱线,基体匹配和同步背景校正法消除了高钨基体的影响和光谱干扰,确保了方法的可靠性.背景等效浓度值从5 μg/L (Nb)至18 μg/L(Fc),元素检出限从4 μg/L (Nb)至13 μg/L (Fe).方法用于钨基硬质合金样品中上述合金或杂质元素的测定,RSD＜3％,加标回收率在97％～104％之间,测定结果与国家标准方法检测结果对照一致.%The tungsten-based hard alloy samples (such as tungsten-cobalt and tungsten-nickel) were digested by high pressure closed microwave heating method using nitric acid-phosphoric acid (V(HNO3) : V(H3PO4)=5 :1) as digestion reagent. After dilution with water, the content of Co, Ni (0.005%-10%), Fe, Nb, Ta, V, Cr and Mo (0. 005%-l%) in digestion solution was directly determined by microwave digestion-inductively coupled plasma atomic emission spectrometry (ICP-AES). The effect of nitric acid and phosphoric acid concentration on sample digestion was investigated. The optimal digestion conditions such as microwave control parameters were studied. The sample digestion method by microwave digestion was established. The matrix tungsten was complexed with inorganic reagents, avoiding the loss of some elements due to the precipitation of tungstic acid and the spectral interference due to the use of organic complex reagents. The results showed that the following digestion procedure was good : the temperature was increased to 130 ℃ within 5 min and kept for 5 min; then, it was increased to 190 ℃ within 5 min and kept for 15 min. The effect of high content matrix tungsten and spectral interference were eliminated by selecting analytical lines, matrix matching and synchronous background correction. The reliability of method could be guaranteed. The background equivalent concentration was from 5 μg/L (Nb) to 18 μg/L (Fe), and the detection limit was from 4 μg/L (Nb) to 13 μg/L (Fe). The proposed method was applied to the determination of alloy or impurity elements in tungsten-based hard alloy samples. The relative standard deviation (RSD) was less than 3% , and the recovery rate of standard addition was 97%-104%. The determination results were consistent with those obtained by national standard method.
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