纯化学物质校准-高频燃烧红外吸收法测定镍铝粉末中的碳

镍基粉末中碳含量的分析质量直接影响材料的性能,但由于碳含量范围较宽,且测定干扰不同,最佳测量条件不一致,更无国家标准方法。高频燃烧-红外吸收法已广泛用于新型材料(如复合碳硅锰铁)中碳和硫的分析,本文基于前期测定镍基钎料以及镍基自熔合金的研究,采用高频燃烧-红外吸收法测定镍铝粉末中的碳,实验中选择纯铁与钨锡作助熔剂,高温燃烧分解样品,通过优化助熔剂用量及其添加顺序、样品称样量等测定条件,获得了较为准确的结果。该方法用于实际样品中碳的测定,相对标准偏差小于1.2%(RSD,n=11),加标回收率为98.0%~105.0%。本方法采用的助熔剂解决了样品导磁性差、燃烧易飞溅等问题,并且针对新型材料缺少标准样品,根据待测样品含量配制相应浓度的基准物质碳酸钠绘制校准曲线,消除了无标准校正的影响,提高了分析结果的准确性。该方法可分析镍铝粉末中含量在0.005%~0.60%范围的碳,也可为制定镍基粉末中碳的标准分析方法提供依据。

Determination of Carbon in Ni-Al Powder by the Pure Chemical Substance Calibration-high Frequency Combustion Infrared Absorption Method

The carbon in Ni-based powder directly influences the property of the material. However, there is no national standard method to determine carbon content in Ni-based powder, according to the wide content range of carbon, different interferences and inconsistent optimal measuring conditions. The High Frequency Combustion-Infrared Absorption Method is already widely used to determine carbon and sulfur in new materials (such as carbon ferro-silico-manganese). Based on the preliminary study on Ni-based brazing material and Ni-based self-fluxing alloy, the high frequency combustion infrared absorption method is used to determine carbon content in Ni-Al powder. The sample is burned at high-temperature and decomposed by adding the flux of Fe and W-Sn fluxes. The measurement conditions such as flux adding amounts, sequence and sample weight have been optimized to obtain accurate results. The method has been applied to the determination of practical samples with the relative standard deviation of less than 1.2% and recovery rate of 98.0%-105.0%. The flux used by the method solves the problems of bad conductivity and splashing during burning. As new materials fall short of standard materials, the calibration curve is prepared by standard sodium carbonate relating to the carbon content, which solves the problem of no reference material and also improves the accuracy. The provided analytical method is not only suitable for the analysis of carbon in Ni-Al power within the carbon content range of 0.005%-0.60%, but also provides the basis for the development of a carbon standard analysis method for nickel-based powder.