Research on the Sorption Performance Test Method of NEG by Constant Pressure Method Based on the New Constant Conductance Element

In this work,we use the improved constant pressure method to test the sorption performance of non-evaporable getter (NEG) for hydrogen.The new constant conductance element is installed between the gas chamber and the inspiratory chamber to provide controllable air inlet flow with a needle valve while maintaining the constant sorption pressure during the sorption test.By measuring the pressure changes in the gas chamber,we can calculate the sorption performance parameters of NEG.The new constant conductance element used in the experiment is a glass-silicon molecular flow leak,and the conductance of H₂ at 25℃is about 5×10^-12 m³/s.It can achieve molecular flow at an atmospheric pressure.During several hours of testing,the sorption pressure rose by 2.843×10^-5Pa/h.The system can test the sorption capacity of different getters under different sorption pressures and temperatures.The results show that when the sorption pressure is constant,the hydrogen absorption performance of the Zr-Fe getter is the best at about 50℃.When the temperature is constant,the higher the sorption pressure,the better the performance.Besides,under the same test conditions,the hydrogen absorption performance of the Zr-Fe getter is better than that of the Zr-Al getter.