惰气熔融-热导法测定高含氮量碳氮化钛粉末中氮含量

由于传统碳氮化钛中氮元素的测量方法有一定局限性，仅在氮含量5%及以下时才能保证测量精度，基于此，建立了一种惰气熔融-热导法测定高含氮量碳氮化钛粉末中氮含量的方法，可有效解决传统方法的不足，检测上限可增加至14%。检测设备使用ONH分析仪，测试条件优化为试样称取0.1 g，助熔剂采用0.65 g镍囊与0.16 g锡囊组合形式，将试样与助熔剂混合置于高温石墨坩埚内，载气可将熔融状态下释放的氮气输送至热导池进行含量测定。此外，采用“分段式升温”方法，调节仪器分析功率，由1.5 kW梯度增加至3.8 kW，可有效增加试验样品中氮元素的释放率及测量稳定性。测量结果采用钒氮合金与氮化钒铁标样确定样品中氮的校正参数，测定结果的相对标准偏差为0.3%，分析结果与蒸馏滴定法的测定结果一致，该方法的准确度及稳定性完全能满足5%～14%的高含氮量碳氮化钛的测定需要。

A method for determining nitrogen in Ti (C,N) powder with high nitrogen content by inert gas melting thermal conductivity method

Since traditional methods can only measure Ti (C, N) with a nitrogen content of less than 5%, it cannotbe applied to Ti (C, N) with a high nitrogen content. Therefore, a method for determining the nitrogen content ofhigh nitrogen content Ti (C, N) powder by inert gas melt-thermal conductivity method was established, which couldeffectively solve the shortcomings of traditional methods, and the upper limit of detection could be increased to14%. Using an ONH analyzer, the experimental conditions were finally optimized to 0.1 g of the sample mixedwith 0.65 g of nickel and 0.16 g of tin, and then placed into a high-temperature graphite crucible. Carrier gas transportsnitrogen released in the molten state to a thermal conduction tank for determination. In this paper, the“segmentedheating”method was used, the analysis power was gradually increased from 1.5 kW to 3.8 kW. Comparedwith direct heating, the“segmented heating”method can effectively increase the release rate and stability of nitrogen.Under the above conditions, the relative standard deviation of the Ti (C, N) determination results with high nitrogencontent is 0.3%, and the analysis results are consistent with the results of distillation titration. Therefore, theaccuracy and stability of the method can fully meet the needs of the determination of 5% to 14% high nitrogen contentTi (C, N).