Preparation And Hydrogen Sorption Performance Of Ti-Based Hydrogen-absorbing Materials Without Activation

The residual hydrogen in the vacuum working cavity would cause serious harm to GaAs-based power amplifiers.The effective way to solve this problem is to preset the hydrogen getters inside the devices.Due to the low melting point solder used in the GaAs devices,it is required to avoid high temperature activation when using the hydrogen getters.This material used titanium foil with a large hydrogen absorption capacity as the base material.After the surface of titanium foil was treated by acid cleaning,the palladium film was deposited on its surface by magnetron sputtering to prepare the Pd/Ti hydrogen getter without activation before use.The microscopic morphology and cross section of Pd film and crystal structure of the Pd/Ti sample were characterized by SEM and XRD.The chemical states of elements on the surface and inside of Pd film were analyzed by XPS.The depth distribution of elements in the material was analyzed by ToF-SIMS.The hydrogen absorption property of the material was tested by the Sievert’s method.The main contents of the research work are as follows:(1)The oxide layer on the surface of Ti foil was removed by the acid treated.The effect of pickling time on the surface roughness of titanium foil was investigated.The oxidation layer could be effectively removed by pickling for 2 minutes in the acid solution of 1wt%HF and 5wt%HNO3 and 94wt%H2O,and the hydrogen absorption activity on the surface of titanium foil could be restored.(2)The structure of Pd film was optimized by adjusting the process parameters of magnetron sputtering,including sputtering pressure,sputtering time,sputtering power,substrate temperature.The relatively dense columnar structure of Pd film was obtained under the condition that the sputtering pressure was 0.2 Pa,the sputtering power was 150 W,and sputtering time was 150 s.And the Pd film had played a relatively good role of hydrogen permeation layer and protective layer.Under the test temperature of 27℃ and hydrogen pressure of 1000 Pa,the hydrogen absorption of the samples after being exposed to atmosphere for 24 hours can reach 1.44 Torr-L/cm2 in 12 hours.(3)The mechanism of the recovery activity after vacuum annealing was analyzed by XPS.The kinetics of hydrogen absorption was studied by ToF-SIMS and XRD.The results show that the properties of the material were improved significantly after the vacuum annealing treatment,and the surface of Ti foil covered by Pd film had changed from oxidation state to active metal state.(4)The environmental resistance of the Ti-based hydrogen absorbing materials was carried out.The changes of the hydrogen absorbing properties of the samples after exposure to the atmosphere for different days were studied.The hydrogen absorbing properties of the samples under different test conditions were studied.The results show that the hydrogen absorption of the samples exposed to the atmosphere for 8 days can reach 1.2 Torr-L/cm2 when the test time reaches 12 hours.Pd film as a protective layer plays a good role.With the increase of hydrogen absorption pressure and test temperature,the hydrogen absorption performance of the sample becomes stronger.