| The palladium-based alloy membrane has unique permeability and high permeability to hydrogen,and has broad application prospects in the fields of hydrogen production,application,recovery and detection.The ruthenium metal has high hardness,strong corrosion resistance,and high melting point.The addition of ruthenium helps to improve the mechanical properties and thermal stability of the palladium alloy,and can improve the working life of the alloy film at high temperatures.The palladium ruthenium membrane has excellent tolerance to various impurities such as HCl,SiHCl3,CO,CO2,CH4,and its application in membrane reactors has also received extensive attention from researchers.In this paper,a porous 316L stainless steel tube modified by a titanium oxide ceramic barrier layer is used as a substrate,and a dense continuous palladium film and a ruthenium film are sequentially deposited by sequential chemical plating,and the palladium-ruthenium film layer is heat-treated to alloy it.Using X-ray diffraction(XRD),scanning electron microscopy-energy spectroscopy(SEM-EDX),Auger electron spectroscopy(AES),and hydrogen penetration test,the structure,micro-morphology and composition distribution of the palladium-ruthenium film were studied The hydrogen permeation flux of the palladium-ruthenium membrane was tested,and the thermodynamic and kinetic mechanism of hydrogen infiltration in the palladium-ruthenium membrane was discussed.Obtain the following research results:(1)A stainless steel anti-porous layer and a titanium oxide ceramic layer were prepared on the surface of porous 316L stainless steel tube by dipping-pulling-sintering method.The activation technology is optimized,and the palladium acetate impregnation activation method is used to obtain uniform palladium particles on the modified substrate surface.A palladium film with a thickness of about 2.5-3 ?m is deposited on the surface of the activated sample by using electroless plating technology.The surface of the palladium film is smooth,and the structure is dense and defect-free;(2)The preparation technology of electroless ruthenium plating is optimized,and the deposition rate of ruthenium is improved under the conditions of a temperature of 75,a?pH value of the plating solution of 12 and a hydrazine concentration of 15%.The thickness of the palladium-ruthenium composite film is about 3 ?m,the surface is flat,the thickness of the ruthenium layer is about 40-60 nm;(3)The process of alloying heat treatment of the palladium-ruthenium composite membrane was carried out by using the process of heating up to 450? in Ar atmosphere,followed by heat preservation in H2 atmosphere for 24 hours.The results of XPS etching showed that the interdiffusion components of palladium and ruthenium tended to be uniform,and XRD results showed that the characteristic peak of ruthenium disappeared,and palladium and ruthenium were partially alloyed;(4)At 450?,the hydrogen transmission rate of the pure palladium membrane is 6.04×10-9 mol·m-1·s-1·Pa-0.5;the hydrogen transmission rate of palladium-ruthenium composite membrane is 8.09×10-9 mol·m-1·s-1.Pa-0.5,which is 1.3 times that of pure palladium membrane;the hydrogen permeability of alloyed palladium ruthenium membrane is 7.31 ×10-9 mol·m-1·s-1·Pa-0.5,which is between pure Between the values of palladium and palladium-ruthenium composite membranes;(5)In the first cycle of 96-hour hydrogen permeation test,the hydrogen permeability of the palladium-ruthenium composite membrane at 450? was 9.72×10-9 mol·m-1·s-1·Pa-0.5.The hydrogen permeability of the membrane was reduced by 22%in the second cycle.With the extension of the test time,the hydrogen flux of the palladium-ruthenium composite membrane slowly recovered,and during the 96-hour hydrogen permeation cycle,the hydrogen permeability of the palladium-ruthenium composite membrane was always higher than that of the pure palladium membrane. |
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