Study On Corrosion And Electrodeposition Of Cathode Plate Interface For Electrolytic Copper Powder

Electrolytic copper powder has dendritic morphology,large specific surface area,good conductivity,excellent molding and sintering properties.It is an indispensable industrial metal raw material.In the process of industrial production,the copper cathode plate is in the environment of high temperature,strong acid and strong current for a long time in the process of industrial production.The place 1?3 cm above the liquid level presents serious linear local corrosion characteristics.However,the theoretical research on the corrosion mechanism of copper cathode plate above the liquid level in the electrolytic process is basically blank,which can not effectively guide the relevant corrosion protection,resulting in a short life of copper cathode in industry.Therefore,the corrosion mechanism of copper cathode interface under electric field is systematically studied by using self-designed experimental device,combined with machine learning analysis,finite element simulation,density functional theory and other computer-aided technologies.On this basis,the protective measures of dynamically repairing three-phase interface corrosion grooves by electrodeposition environment are proposed,and improved the study of three-phase interfacial corrosion under the action of electric field.The global corrosion characteristics of copper cathode interface were studied in this paper.Combined with the self-designed periodic electrolytic corrosion device and three regression algorithms of random forest,k-nearest neighbor and multilayer perceptual neural network,the prediction model and weight analysis model of copper cathode global corrosion behavior with model accuracy of 97%are established.The results of weight analysis model show that the current density(weight 1)has the greatest influence on the corrosion of full immersion area;The corrosion process in the gas phase near the liquid surface is mainly affected by the synergy of current density(weight 0.174),electrolyte temperature(weight 0.203)and liquid level fluctuation period(weight 0.153);The corrosion process in the far liquid surface vapor area is mainly affected by the current density(weight 0.575).The influence mechanism of environmental characteristics on the corrosion process of copper cathode interface is proposed in this paper.Based on the corrosion rate distribution curve and electrochemical characterization,the corrosion mechanism of copper cathode at three-phase interface under electric field was proposed.It is found that there is a certain degree of cathodic protection in the gas phase area near the liquid level.When the current density increases from 600 A/m2 to 1400 A/m2,the corrosion rate in the gas phase area near the liquid level decreases by 55.4%;Constant potential experiments show that the reaction rate of hydrogen evolution will change the area and corrosion range of the gas phase area of the liquid surface.The distribution law of physical field in full immersion area and three-phase interface area is analyzed.The coupling models of electric field,flow field and concentration field in the full immersion area and three-phase interface area are established by using the finite element method.The research shows that the electric field direction in the three-phase interface area has a larger deflection than the normal direction of the cathode surface,and the electric field intensity of the cathode plate gradually decreases with the increase of the height above the liquid.When it is 3?4 mm away from the liquid surface,the electric field intensity decreases from 1000 A/m2 in the full immersion area to 20?50 A/m2.The resulting concentration difference makes the copper ion in the far liquid surface gas phase area migrate to the near liquid surface gas phase area.The synergistic effect of special electric field and concentration field has a significant impact on the electrochemical reaction and mass transfer process.The competitive corrosion mechanism and electrodeposition dynamic process in the three phase interface area were revealed.The influence of powder growth in continuous liquid layer environment was studied by a self-designed three-phase interfacial liquid layer control device.The results show that the powder deposition morphology and particle size distribution are related to the variation trend of three-phase interface physical field,and the variation trend of current density and copper ion concentration is basically consistent with the analysis results of electric field and concentration field model;The hydrogen atom adsorption energy at different adsorption sites and different coverage of each crystal surface is calculated by density functional theory,which generally exceeds the bond energy existing in the double hydrogen atom structure(2.35 eV).It is confirmed that at the thin liquid layer,hydrogen has the possibility of dissociation adsorption on the copper crystal surface and selective growth of the crystal surface;The corrosion evolution mechanism in the process of alternating wetting and drying at three-phase interface under the action of electric field was proposed,and the competition mechanism between electrodeposition process and oxygen concentration battery in different stages of corrosion process was clarified;Based on the dynamic mechanism of powder nucleation growth at three-phase interface,the protective measures of dynamic repair of corrosion gullies at three-phase interface by electrodeposition environment were proposed.And a new method for preparing micro nano powder by using the similar environment of three-phase interfacial electrodeposition,which can control the preparation of spherical like powder with narrow particle size distribution from tens of nanometers to several microns without additives.