The Research On Electrophoretic Deposition Technology And Film Formation Test Of Nano-alumina

In recent years,thin films prepared by electrophoretic deposition of nanomaterial have attracted much attention due to their excellent protective properties.As a key part of the technology,the condition,process and film forming technology for electrophoretic deposition will all have an impact on the protective effect of thin films.Therefore,theoretical analysis,simulation and experimental exploration of electrophoretic deposition technology are carried out to clarify the mechanism of electrophoretic deposition and the characteristics of film formation.The technology of reinforced electrophoretic coating by electrodeposition is also studied in order to perfect nano-composite electrophoretic deposition technology.It will promote its engineering application value.Theoretical analysis is carried out around the theory of particle suspension,electrophoresis process and deposition process.The charging mechanism and stable suspension theory of nano-alumina particles are clearly defined.Then,the force and velocity of particles and the flow are theoretically analyzed.The relationship between electric field intensity and particles motion is confirmed,and so is the flow characteristics of suspended particles.Finally,the deposition mechanism is determined,and the reasonable deposition mathematical model is established.The theoretical analysis results provide theoretical support for simulation modeling.According to theoretical analysis results,in COMSOL multiphysics simulation environment,simulation analysis model for electrophoretic deposition is established,results are solved,and characteristics of electric field,particle-fluid coupling field and deposition field are analyzed.Simulation results of electric field show that the distribution of electric field intensity is more favorable for homogeneous deposition after the deposition of insulating nanoparticles.Results of particle-fluid coupling field show that voltage is an important parameter affecting the movement of particles and the flow.As voltage is too large,particles motion will have a significant disturbance effect,which is detrimental to uniform deposition of particles.Simulation results of deposition field show deposition voltage and time are important control parameters.When extending the time or reducing the voltage appropriately,the uniformity and controllability of film forming will be improved.Based on theory and simulation results,electrophoretic deposition experiments of nano-alumina are carried out.A test platform is built up,and electrophoretic solution of nano-alumina and film forming process are prepared.Deposition mass and surface morphology will be characterized after experiments.Experimental results show that macroscopical distribution of the deposition is relatively uniform.It is obvious thicker at the edge of the electrode,which is highly consistent with simulation results.Electrical conductivity,aging time,deposition voltage and deposition time are selected as the main control parameters,whose influence on electrophoretic deposition will be characterized by deposition mass and surface topography.Comparing experimental results of deposition voltage and time with simulation results,the validity of simulation analysis model and the feasibility of simulation analysis of electrophoretic deposition are validated.The electrodeposition technology was applied to reinforce electrophoretic deposition coating and perfect the nano-composite electrophoretic deposition technology.The composition and surface morphology of composite films were tested to confirm the deposition of metal nickel and its positive effects on thin films.The micro-hardness test of composite film and pure nickel coating proved that composite films had better protective properties.Films with different control parameters of electrophoretic deposition were contrastively tested,which were combined with test results of electrophoretic deposition,to analyse and confirm the influence of parameters on composite films.Theoretical and experimental results confirmed that nano-composite electrophoretic deposition film had better protective properties than those prepared by conventional electrophoretic deposition and electrodeposition.The results of this research lays the foundation of theoretical simulation and experimental research for the popularization and application of nano-composite electrophoretic deposition technology.