高频燃烧红外吸收法测定钒铝合金中碳

控制样品粒度为100～160目(即96~147 μm),称取0.10～0.20 g样品,选择1.8 g钨粒、0.30 g纯铁、0.15 g锡为助熔剂,用碳质量分数为0.006%~0.069%的钛合金标准物质建立校准曲线,建立了高频燃烧红外吸收法测定钒铝合金中碳含量的分析方法。在优化的实验条件下,以碳质量分数为横坐标,以其对应的峰面积为纵坐标绘制校准曲线,其线性回归方程为y=5.878+859.4 x,相关系数r=0.999。方法检出限为0.001 1%,测定下限为0.003 8%。称取一定量的铝屑和钒铁标准样品,按照AlV55钒铝合金的成分配比混合配制成钒铝合成样品,按照实验方法进行测定,测定值与理论值基本一致。将方法应用于铝钒合金实际样品(AlV55、AlV65、AlV75和AlV85)中碳的测定,结果的相对标准偏差均小于10%(n=7)。钛合金中碳的加标回收率为92%～107%。对于碳质量分数为0.040%的铝钒合金(AlV55),其扩展合成不确定度为0.002 6%。

Determination of carbon in vanadium-aluminum alloy by high frequency infrared absorption method

The particle size of sample was controlled at 100-160 mesh (96~147 μm), and 0.10-0.20 g of sample was fused with 1.8 g of tungsten particle, 0.30 g of pure iron and 0.15 g of tin as flux. Then, the certified reference material of titanium alloy with carbon mass fraction of 0.006%-0.069% was used to create the calibration curve.Consequently, an analysis method of carbon content in vanadium-aluminum alloy was established by high frequency combustion infrared absorption method. Under the optimized conditions, the calibration curve was plotted with the mass fraction of carbon as abscissa and its peakarea as ordinate. The linear regression equation of calibration curve was y=5.878+859.4x with correlation coefficient of r=0.999. The detection limit and lower limit of quantitation was 0.001 1% and 0.003 8%, respectively. Certain amounts of aluminum scrap and vanadium-iron certified reference materials were used to prepare synthetic vanadium-aluminum samples according to the composition of AlV55 vanadium-aluminum alloy. The synthetic samples were determined by the proposed method, and the results were basically consistent with the theoretical values. This method was applied to the determination of carbon in actual vanadium-aluminum alloy actual samples (AlV55, AlV65, AlV75 and AlV85). The relative standard deviations (RSD, n=7) were less than 10%. The recoveries of carbon in titanium alloy were between 92% and 107%. For thevanadium-aluminum alloy sample(AlV55) with carbon content of 0.040%, the expanded combined uncertainty was 0.002 6%.