Preparation And Applications Of Hydrogen Storage Films

The hydrogen storage film is the core material used for the tritium target for neutron generators,and its hydrogen storage capacity is a key indicator that determines the performance of the tritium target.In addition,the energy conversion efficiency can be improved by introducing hydrogen storage film into the explosive foil of laser initiating explosive devices to realize the combination of hydrogen explosion energy and chemical energy.In this thesis,aiming to solve the problems such as small hydrogen storage,easy pulverization and low operating temperature in the tritium target for neutron generator,the tritium target of TiMo alloy film was prepared by magnetron sputtering.The effects of substrate temperature,Mo content and operating temperature on the hydrogen storage performance of TiMo film tritium target were studied.In addition,in order to improve energy conversion efficiency of laser initiating explosive devices,it is proposed to use hydrogen storage films as laser-driven flyer transducers.The magnetron sputtering method was used to prepare MgAl thin films.The effects of different Al contents on the hydrogen absorption properties of MgAl thin films and the effects of hydrogen contents on the speed of laser flyers were mainly investigated.The main work of the thesis is as follows:1.A tritium target structure for neutron generator is designed.The structure is mainly composed of 4 parts,which are Cu base,Au barrier layer,TiMo alloy hydrogen storage layer,and Ta protective layer.The Cu substrate has a diameter of 15 mm,a thickness of 2 mm,and a 200 nm thick Au barrier layer is deposited to prevent the hydrogen in the hydrogen storage layer from diffusing to the Cu substrate.A 20 nm thick Ta protective layer can generate a dense layer of Ta₂O₅ in the air,which can effectively prevent the diffusion of water vapor and oxygen in the atmosphere to the hydrogen storage layer.Au barrier layer,TiMo hydrogen storage layer and Ta protective layer were deposited by magnetron sputtering method.The prepared samples were subjected to hydrogen storage treatment by high-temperature pressurization.The static volume method was used to test the hydrogen absorption of the tritium target.The results show that the surface of the TiMo film is smooth and free of defects,and the TiMo alloy films with Mo content of 40 wt.%and 55 wt.%have a stable?-Ti phase structure.As the Mo content increases,the hydrogen storage of the TiMo film tritium target decreases.The hydrogen storage of the film samples with Mo content of 0 wt.%,23 wt.%,and 40 wt.%are 7 wt.%,6.23 wt.%and 1.8 wt.%,respectively.As the substrate temperature increases,the hydrogen storage of the sample increases gradually.The TiMo thin film tritium target with a Mo content of 40%has a hydrogen storage capacity of 1.81 wt.%and 3.01 wt.%at a substrate temperature of room temperature and 300 ^oC,respectively.The hydrogen storage capacity of the tritium target sample with a Mo content of 40 wt.%increased gradually with the increase of the operating temperature,and the hydrogen storage capacity of the tritium target reached 12.95 wt%at the working temperature of 280 ^oC after five hydrogen absorption and emission experiments,and the sample did not show any pulverization and crack.Ti₃₈Zr₃₆Mo₂₅ and Ti₇₂Al₁₃Mo₂₅ ternary alloy films are formed by doping Zr and Al metals in TiMo alloy film.The maximum hydrogen absorption content of Ti₃₈Zr₃₆Mo₂₅ film tritium target is 1.36 wt.%.And the maximum hydrogen absorption content of Ti₇₂Al₁₃Mo₂₅ film tritium target is 2.87 wt.%.The anti-pulverization performance and hydrogen storage capacity of the tritium target of the multilayer film structure are effectively improved.2.Five kinds of hydrogen storage films for laser flyers,such as Mg,Mg₈₇Al₁₃,Mg₅₉Al₄₁,Mg₂₅Al₇₅ and Al,were prepared on sapphire substrate with a diameter of 5.8 mm by magnetron sputtering technology.During the deposition process,the hydrogen storage film was deposited by argon hydrogen mixture with a gas flow ratio of 3:1.The XRD diffraction spectrum results were used to calculate the hydrogen content in the sample.The research results show that the film deposited in the argon-hydrogen mixture is rougher and has more defects than the film deposited in the pure argon atmosphere.The XRD test results show that the hydride phase is formed in Mg₈₇Al₁₃ and Mg₅₉Al₄₁ film.The relative content of MgH₂ in the Mg₈₇Al₁₃ film is 30 wt.%,and the content of MgH₂in the Mg₅₉Al₄₁ film is 30.5 wt.%.Compared with the non-hydrogen storage film,the thermal conductivity of the hydrogen storage film is reduced,and the higher the hydrogen storage content,the worse the thermal conductivity of the film.At the light wavelength of 1064 nm,the light absorption rates of Mg and MgH films are 23%and 32%,respectively.The light absorption rates of Mg₈₇Al₁₃ and Mg₈₇Al₁₃H films are 25.7%and43.5%,respectively.It shows that the absorption rate of the hydrogen storage film to the laser is higher,which is conducive to improving the energy conversion efficiency of laser-driven flyer.The deposited film samples were assembled into a laser impact plate detonator,and PDV was used to test the speed of the flyer speed.The flyer material is 50?m thick Al foil.The test results show that the maximum speed of the flyer driven by pure Mg film is 1800 m/s,the maximum speed of the flyer driven by pure Mg film after hydrogen absorption is 2006 m/s,and the speed of the flying plate is increased by 11.4%.The highest flying speed of the Mg₈₇Al₁₃ film is 1381 m/s,and the highest speed of the Mg₈₇Al₁₃ thin film after hydrogen absorption is 1589 m/s,which is about 15%higher.The flyer speed of the Mg₅₉Al₄₁,Mg₂₅Al_75,and Al films after hydrogen absorption are1741 m/s,1627 m/s,and 1968 m/s,respectively.Compared with the explosion film without hydrogen storage,the flying speed of the laser impact detonator has been significantly improved,indicating that the combination of hydrogen detonation energy and explosion energy has been realized by introducing hydrogen into the laser detonator,and the energy conversion efficiency of the detonator has been significantly improved.