Nitrogen in titanium alloys mainly exists in the form of nitrides, such as TiN, VN, FeN, etc., with only a small portion of nitrogen present in atomic form. Excessive nitrogen content in titanium alloys can lead to macroscopic microstructure porosity and even the formation of bubbles. This leads to a decrease in toughness, an increase in hardness, and an increase in notch sensitivity, greatly hindering the application of titanium and titanium alloys. Therefore, in the production of titanium and titanium alloys, it is necessary to accurately analyze the nitrogen content in sponge titanium, titanium and titanium alloys, and strictly control their content to ensure product quality. Due to the high melting point of nitrides in titanium and titanium alloys (such as titanium nitride with a melting point of 2950 ℃), it is difficult to directly determine their content using pulse inert gas melting method. Researchers have achieved the determination of nitrogen content in sponge titanium, titanium, and titanium alloys using LECO's TC600 oxygen and nitrogen combined analyzer pulse inert gas melting thermal conductivity method by selecting and combining different graphite crucibles, fluxes, sample weighing amounts, and heating powers.

The experimental principle is as follows: add flux to the sample and place it in a graphite crucible, protect it with inert gas (helium), and release oxygen and nitrogen at sufficient temperature. Oxygen combines with carbon to form CO, and nitrogen is released in the form of N2. The gas released from the sample is carried by an inert gas and heated with rare earth copper oxide to convert CO into CO2, H2 into H2O, which is absorbed by alkali asbestos and H2O is absorbed by anhydrous magnesium perchlorate. Then, nitrogen enters the thermal conductivity measurement cell in the form of N2, and the output of the Huisi bridge is integrated and compared with the reference material to respond, displayed as the percentage content of nitrogen.

The experimental results are as follows: A graphite high-temperature crucible pre loaded with 0.050g of high-purity graphite powder was used, and a high-purity nickel basket was used as the flux. The optimal measurement conditions for the combined tester were obtained as follows: degassing power of 5600W, analytical power of 5000W, degassing time of 20s, cooling time of 15s, flushing time of 15s, and integration time of 65s. Through the determination of standard samples and comparison with data from other units, as well as the use in production testing, it has been proven that this method is simple to operate, fast in analysis speed, accurate in data, and precise in meeting the needs of scientific research and production.