The Research Of The Nanoporous Copper Preparated By Dealloying

In metallurgy, dealloying is defined as selective corrosion of the less noble constituent from an alloy in a corrosive environment. Dealloying is by far the most often applied method to generate macroscopic 3D as well as 2D (thin film) and 1D (nanowire) samples of low-density nanoporous metal foams for nanomechanical testing.Nanoporous metals made by dealloying display novel properties in a wide range of applications such as catalysis, chemical and biosensors, fuel cell electrodes, and so forth, and they are a rapidly growing class of high-porosity materials. The present research concentrates on preparations of multi-nanoporours metals from different alloys, and is driven by the desire to create functional materials with unique physical, chemical, and mechanical properties where the material properties emerge from both morphology and the material itself. The strong connection between mechanical behavior and the characteristic internal length scale of the structure as determined by pores and ligaments. Cellular metals exhibit low densities, high surface area, high specific stiffness and strength, high energy-absorbing capabilities and novel thermal properties comparing to solid metals. They have been widely used in many fields for their multi-functionality, such as aircraft, spacecraft, automobile and offshore oil production platforms. So we reviewed preparation of nanoporous copper .Two kind of fabricating methods of copper-zinc alloy for nanoporous copper have been developed. The conclusions of the thesis can be listed as follows:(1)The thin films has been successfully deposited on the float glass and monocrystalline silicon by magnetron sputtering system. The influence of the different power, deposition pressure and time on the element distribution, the thickness , surface topography,surface roughness, crystal structure, resistivity change and stability of films has studied, and get the best process parameters.(2)The Cu62Zn38 alloy films were deposited by the DC magnetron sputtering. Porous copper materials have been fabricated by dealloying of Cu62Zn38 alloys films in H₂SO₄ solution.The composition of precursor Cu62Zn38 alloy, porous structure and fracture surface morphology of porous copper have been investigated by means of X-ray diffraction,scanning electron microscopy and the energy dispersive X-ray spectrum analysis. In deposit process formed amorphous structure because of atoms cannot obtain enough energy to rearrange. The films were dealloyed in H₂SO₄ solution etching of zinc component, resulting in formation of nano-scale porous copper films, in 2 mol/L H₂SO₄ solution and 7 mol/L H₂SO₄ solution respectively, the corrosion way of Cu62Zn38alloy is nonuniform.Dealloyed under free corrosion in concentration 2mol/L H₂SO₄ solution, formed the pore with a lower density, the alloy films were corroded drastically in 7mol/L H₂SO₄, the films peeled off the substrate and became crisp, could not been corroded enough due to their overlap structure decreased the corrosion area. So it was possibly difficult to form uniform pore surface. In 5 mol/L H₂SO₄ solution,the corrosion way of Cu62Zn38 alloy is uniform.Under free corrosion in solution 5mol/L H₂SO₄ solution formed a three-dimensional network structure, including smooth ligaments with an average diameter of around 92.7nm and disorderly pore diameter of approximately 94 nm.(3)Monolithic nanoporous copper (NPC) ribbons can be fabricated through chemical dealloying of melt-spun Zn-Cu alloys with 10-20 at % Cu under free corrosion conditions. The microstructure of these NPC ribbons was characterized using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. The experimental results show that the melt-spun Zn -Cu alloys with 10-20 at % Cu are composed Cu0.64Zn0.36and ZnCu intermetallic compounds. Cu0.64Zn0.36 can be fully dealloyed, and the synergetic dealloying ZnCu in the two-phase Zn-Cu alloys results in the formation of NPC with a homogeneous porous structure. The NPC ribbons exhibit an open, bicontinuous interpenetrating ligament-channel structure. NPC is a promising high strength/low density material due to its high porosity .In addition, bulk NPC rods and slices can also be synthesized using the same strategy.Two kind of fabricating methods of copper-zinc alloy for nanoporous copper have been developed,and nanoporous copper had been made and investigated in this paper.It will be helpful to extend application of nanoporous copper.