GB/T 15076.13-2017 in English

《GB/T 15076.13-2017钽铌化学分析方法 第13部分：氮量的测定 惰气熔融热导法》由TC243（全国有色金属标准化技术委员会）归口，TC243SC3（全国有色金属标准化技术委员会稀有金属分会）执行，主管部门为中国有色金属工业协会。

GB/T 15076.13-2017 Methods for chemical analysis of tantalum and niobium - Part 13: Determination of nitrogen content - Inert gas fusion thermal conductivity method

1 Scope

This part of GB/T 15076 specifies a method for the determination of nitrogen content in tantalum and niobium.

This part is applicable to the determination of nitrogen content in tantalum and niobium. Determination range: 0.0005%–0.400%.

2 Principle

The test portion and flux are added to the high-purity graphite crucible, heated and fused in the atmosphere of inert gas (helium), in which oxygen combines with the carbon in the crucible to generate a mixture of carbon monoxide and carbon dioxide, with nitrogen released in the form of nitrogen gas. Carbon monoxide is partially oxidized into carbon dioxide. Then carbon monoxide and carbon dioxide in the gas pipeline are absorbed and separated respectively, and the remaining nitrogen gas enters the thermal conductivity detector with the carrier gas (helium). The detector outputs a signal, and the calculation system calculates the nitrogen content with the mass of the sample.

3 Materials

3.1 Helium, with a volume fraction of not less than 99.995%.

3.2 Argon gas/ nitrogen gas, with a volume fraction of not less than 99.9%.

3.3 High-purity nickel foil/nickel basket: ωN ≤ 0.000 2%, nickel foil thickness ≤ 0.10 mm.

3.4 High-purity graphite crucible.

3.5 Reference material/standard sample: Appropriate reference materials, which, in principle, shall have similar chemical composition to that of the analytical sample.

Foreword i
1 Scope
2 Principle
3 Materials
4 Instruments and apparatus
5 Specimen
6 Analytical procedures
7 Precision
8 Test report