杜马斯燃烧法测定钒氮合金中氮

氮含量是钒氮合金质量的重要技术指标之一,目前国内主要采用湿法分析氮,结果可靠但效率低,因此有必要建立快速测定钒氮合金中氮含量的方法。实验探讨了采用杜马斯燃烧法测定钒氮合金中氮的方法,对样品粒径、称样量、燃烧时间、助熔剂用量进行了优化。实验选定条件为:样品粒径不大于0.074mm,称样量0.0400~0.0600g,燃烧时间270s,采用0.1g纯镍和0.1g纯钨作助熔剂。结果表明:在优化实验条件下,氮含量为13.14%~16.64%(质量分数,下同),氮的质量分数与对应的峰面积呈线性关系,校准曲线的线性相关系数r为0.9996。按照实验方法测定钒氮合金有证标准物质中氮,测定值与标准值的相对误差为0.21%~0.38%。方法用于实际样品中13.55%~15.56%氮的测定,结果的相对标准偏差(RSD,n=10)为0.42%~0.50%。

Determination of nitrogen in vanadium-nitrogen alloy by Dumas combustion method

Nitrogen content was one of the important technical indicators for the quality of vanadium-nitrogen alloy. At present, the content of nitrogen was usually determined by wet method in China. The analysis results were reliable, but the efficiency was low. Therefore, it was necessary to establish a rapid method for the determination of nitrogen content in vanadium-nitrogen alloy. The determination of nitrogen in vanadium-nitrogen alloy by Dumas combustion was explored in experiments. The particle size, sample mass, combustion time and flux dosage were optimized. The following conditions were selected: the particle size was not larger than 0.074mm; the sample mass was in range of 0.0400-0.0600g; the combustion time was 270s; 0.1g of pure nickel and 0.1g of pure tungsten were used as flux. The results showed that under the optimized experimental conditions, the mass fraction of nitrogen showed a linear relationship with the corresponding peak area when its content was in range of 13.14%-16.64% (mass fraction). The linear correlation coefficient (r) of the calibration curve was 0.9996. The content of nitrogen in certified reference materials of vanadium-nitrogen alloy was determined according to the experimental method. The relative error between the measured value and the standard value was 0.21%-0.38%. The proposed method was applied to the determination of nitrogen (13.55%-15.56%) in actural samples. The relative standard deviation (RSD, n=10) of the determination results was 0.42%-0.50%.