The Research On Fabrication Technique Of Substrated Palladium-Yttrium Alloy Membrane And Theroy Study Of Surface Adsorption Behavior For Hydrogen Purification

In this paper, the modification technique of microporous stainless steel surface by paste-coating and Sol-Gel mothed was employed to prepare unsymmetrical microporous stainless steel membrane. The property of nano stainless steel powders, TiO2 Gels, micoporous stainless substrate and unsymmetrical microporous stainless steel membranes was determined by TEM and SEM, the dry gas permeation flux was measured by AP90 permeation device. In paste-coating process, the nano-meter stainless steel powder was first deposited on porous stainless steel surface, and a unsymmetrical microporous stainless steel membrane could be obtained, the average pore size of membrane was about 200nm,its dry gas flux was about 200cm -cm" -min" at room temperature and at a pressure difference of 0.1 MPa. The micro-porous steel membrane was further coated with T1O2 membrane by Sol-Gel method, and a composite membrane with pore size of lOOnm was achieved, it had a dry gas flux of 80cm3/cm2-min at room temperature and at a pressure difference of 0.1 MPa.The technique of Ion Beam Assisted Deposition (IBAD) was studied on IBAD device,and the target of Pd,Y,Sn,Pb and Pd-8Y was used as sputtering target,the deposition speed differed with sputtering time was deeply and firstly studied,the mechanism of deposition was discussed. SEM and AFM was used to analysis the appearance and microstructure of the obtained membrane, the step device and RBS was employed to measure the membrane thickness, XRD,SAM and XPS was used to analysis the membrane content and membrane adsorption behavior. The membrane thickness would grow with deposition time at a constant voltage and current. The rate of deposition thickness for Pd was 5.53nm/min, 8.33nm/min and 13.0nm/min at ion beam current of 60mA, 80mA and 100mA,respectively. The rate of deposition for Y and PdY was 8.73nm/min and 10.7nm/min at ion beam current of 100mA. By using Pd-8Y as sputter target,controlled the voltage at 20keV,the current at 100mA , the micoporous stainless steel with pore size of 100nm as substrate,Ar flow rate at 6L/min deposition time as 100min,a Pd-8Y membrane with thickness about lum could be achievedThe influence of deposition technique on the properties of membrane was systematically study, Pd and Y was firstly used to find the feasibility of preparing Pd-Y alloy membrane directly by alternatively depositing pure target. The content of Pd and Y was contrasted by using Ar+ beam assisted deposition with no Ar+ beam assisted deposition.From the experiment,by using Pd and Y as target, Ar+ beam as mixing beam, alternatively depositing nano meter Pd and Y, and a Pd-Y alloy membranes with smooth surface,well-distributed content and good structure could be directly achieved,and the feasibility of preparing Pd-Y alloy membrane directly by alternatively depositing pure target was demonstrated.For the difference of melting point of Sn and Pb with Pd and Y,it is difficult at present to preparing Pd-Y-Sn or Pd-Y-Pb alloy membrane directly by alternativelydepositing pure Sn, Pb,Pd and Y target,but it is capable to obtaine the Pd-Y-Sn or Pd-Y-Pb alloy membrane by directly using Pd-Y-Sn or Pd-Y-Pb alloy as target.The compound metarial structure, chemical adsorption thermodynamics and poisoning mechanism of common impurity gas on alloy membrane was deeply studied by theory computation method to solve the poisoning problems in the appliance of Pd-Y alloy membrane. In the study of molecule structure, the Gaussian-98 process and B3P86 method was used, the basis functional of SDD** for Pd, Y, Sn and Pb, 6-311g** for C,H,O,N and S was set.By study the gaseous and solid molecule structure,the compound structure including the ground states, average bond length, Harmonic frequencies,force constants and decompose energy of H2,D2,T2 and impurity gases with Pd,Y,Sn and Pb was firstly obtained. From the result of structure study, H2,D2 and T2 could form M-X line type molecules with Pd,Y,Sn and Pb, could form M-X2 angle type molecules with Y,Sn and Pb,form M-X3 pyramid type molecules,form M-X4 tetrahedron type...