Study of the effect of praseodymium and neodymium on adsorption properties for active gases in non-evaporable Zr-Co base chemical getter and comparing them with yttrium

In this research, a chemical getter with 75%wt zirconium, 22% cobalt, 1.5%wt of praseodymium and 1.5%wt neodymium was synthesized by ball milling. The effect of these elements on the adsorption/desorption properties of the getter was compared with the effect of yttrium. Due to the high activity of non-evaporable getters, oxide layers are formed on the surface. So, for activating a getter these layers must be removed. For this purpose, the samples were first placed at 100 °C for 30 minutes and then were activated at 360 °C for 80 minutes. The results of the adsorption tests in terms of pressure and temperature variations versus time indicated that the activation temperature for the yttrium sample was reduced by about 60 degrees and reached from 260 to 200 °C. The start pressure of the adsorption test in the getter chamber for all samples is 1.5 × 10-5 mmHg. While in the case of Y the final pressure of the reactor was reached to 1.3 × 10-6 mmHg. After completion of the activation process, the connection between the reactor and the vacuum pumps was disconnected to determine the time of vacuum preserving from 0.001 to 0.2 mmHg. The required time to break the vacuum for yttrium containing sample was 4955 seconds, which has the highest value. According to the results, the performance of the Pr, Nd and Y is close to each other, and all of the  these elements reduced the pressure of the system by about ten times and increased the vacuum breaking time to more than 4000 seconds.