| Jet electrodeposition is a branch of electrochemical deposition. As a technology of local highspeed electrodeposition, it has lots of advantages such as high quantity of heat and mass transfer rate,high limiting current density and deposition efficiency. Nano-multilayer films can be preparedtheoretically by controlling current density and deposition time reasonably. Based on the preliminarywork on the metal substrate, multilayer film on silicon surface is prepared and studied in this paperconcentrating on the giant magnetic resistance and dielectric properties. Due to the implementation ofalternating multilayer films technology on metal, a lot of work has been done focusing on the study ofsilicon/multi-layer interface in order to develop the bonding strength, as follows:(1)The flow field of the nozzle was simulated and the experiment was done. To the nozzle widthas1mm, the flow field was simulated by FLUENT in conditions of different inlet flow velocity (flowcapacity) and electrodes distances (△).Take the1mm area under the nozzle as research subject, resultshows the uniformity of the flow field is best when the distance is2mm. fixed-point jetelectrodeposition is studied on△=2mm, practical situation is reflected well by simulation. Theuniformity is best when inlet flow velocity is0.40m/s (Q=485L/h).△=2mm, Q=485L/h is chosen asthe parameter of the subsequent experiment.(2)Proposing a new method for preparation of metal nanoparticles (applied for national inventionpatent) by jet electrodeposition on polished silicon. The process is simple, economical andenvironmental-friendly. The granularity and distribution uniformity is studied by SEM. The resultshows that, with the decrease of the roughness of silicon, the particle shape is mainly of idealspherical and the size decreases, the uniformity has been gradually improved. When the roughnessdecreases under0.023μm, particles reaches to nanometer scale, and distribution uniformity improvedfurther. For current density is300A/dm2and scanning speed is360mm/min, the nanoparticles deposituniformly and well-dispersed.(3)Bonding force between Cu/Co multilayer film and silicon substrate is studied under differentroughness and etching process from the perspective of interface design. It shows that the adhesionbetween silicon and metal multilayer film is mainly consist of mechanical force. Based on this, thisstudy use research group’s special processing technology to design a special riveting structure onsilicon substrate(invention patent:CN101101937A), namely to use EDM-ECM composite process to obtain special surface morphology of overlapped holes. Compared with etching technique on silicon,this kind of special structure make the interface have more mechanical connection spots, multilayertest research shows that the interface bonding strength increased by more than two times.(4)In addition, Corrosion resistance of Co/Cu multilayer is tested by electrochemical method.Study shows, the influence of current density and scanning speed to the corrosion resistance iscorroding to the law to the surface topography. The increase of current density contributes to theimprovement of corrosion resistance, corrosion resistance is best when the Jcuis300A/dm2and Jcois100A/dm2;When scanning speed is360mm/min, the leveling effect of deposits to the Sisubstrate is best, which at this point make the corrosion resistance the best. |
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