The Preparation And Performance Analysis Of Cu/Ni And Cu/Ag Metal Multilayers

Cu/Ni and Cu/Ag multilayers with different modulation wavelength wereprepared by electrochemical method including a single bath electrodeposition and adual bath electrodeposition. Cu/Ag multilayers with different modulation wavelengthwere prepared by magnetron sputtering. The microstructures, microhardness of themultilayers were investigated. Nano indentation experiments and surface XRD testwere performed.The results indicated that Cu/Ni multilayers prepared by a single bathelectrodeposition have smooth layers and clear lamellar structure. Microhardnessmeasurement show that when the modulation wavelength is greater than100nm, themicrohardness increases with the decrease of modulation wavelength, and thechanging regularity of microhardness matches the Hall-Petch principle, while less than100nm, the microhardness decrease with the decrease of modulation wavelength. Thepeak microhardness occurs at the modulation wavelength about100nm. XRD testingshows that the stress in nanoscale multilayers is pressure stress and the strong (110)texture is formed.in Ni layers, in Cu layers there is no obvious texture formed.Cu/Ag multilayers prepared by a dual bath electrodeposition have a little unevenlayers but the lamellar structure is clear and the modulation cycle is obvious.Microhardness measurement show that when the modulation wavelength is greaterthan100nm, the microhardness increases with the decrease of modulation wavelength,while less than100nm, the microhardness decrease with the decrease of modulationwavelength. The peak microhardness occurs at the modulation wavelength about100nm. XRD testing shows that the stress in nanoscale multilayers is pressure stress.Cu/Ag multilayers prepared by magnetron sputtering have smooth layers andclear lamellar structure, each cycle of layer thickness keeps consistent Nano creasingtest show that when the modulation wavelength is in the experiment test range(15~120nm), the hardness increases with the decrease of modulation wavelength. When the modulation wavelength is greater than45nm, the changing regularity ofmicrohardness matches the Hall-Petch principle. The nano indentation experimentsshows that the elasticity modulus of multilayers have no obvious change with thechange of modulation wavelength.Based on Cheng’s electron theory, the starting softening points of Cu/Nimultilayers prepared by a single bath electrodeposition is explained. In Cu/Agmultilayers prepared by magnetron sputtering, when the modulation wavelength is15nm, there still has no hardness softening phenomenon appeared. Based on thedifferences of layers boundary structure between the multilayers prepared byelectrochemical methods and physical methods, the strengthening mechanism of themultilayers are discussed.