Study On The Preparation And Ytterbium Doped Aluminum Electrodeposited Coating And Micro-arc Oxidation Film

Since steel materials are easily corroded in the air,it is particularly important to protect and reduce the loss of steel materials due to corrosion.Therefore,electrodeposition can be used to protect steel materials.In the development of industrial materials,it is necessary to reduce the cost of materials and at the same time to greatly enrich the various properties of the materials,so the surface modification technology has become particularly important.The micro-arc oxidation process is one of the typical surface modification technologies.The micro-arc oxidation process can give the material more excellent performance.In this thesis,the NaCl-KCl-AlCl₃(molar ratio 1:1:4)three molten salt system is used,and different contents of Yb₂O₃ are added,and electrochemical deposition is carried out under constant temperature conditions to prepare aluminum electrodeposition layers with different ytterbium contents.The influence of different ytterbium content on the properties of the deposited layer.Analyze the phase structure,micro morphology and element composition of the coating by X-ray diffractometer(XRD),scanning electron microscope(SEM)and energy spectrum analyzer(EDS);test the corrosion resistance of the deposited layer by electrochemical methods;pass Micro-hardness meter and micro-thickness meter measure the hardness and thickness of the deposited layer.The results show that the addition of Yb₂O₃ with different molar ratios to the molten salt can effectively improve the microstructure of the deposited layer and improve the electrochemical corrosion resistance of the electrodeposited layer.When the Yb content is 0.29%,the dendritic structure in the grains of the aluminum electrodeposited layer is significantly improved.When the microscopic morphology is the best,the corrosion resistance,hardness and thickness are the highest.Using the pulse oxidation experimental power supply,the prepared electrodeposition layer is subjected to micro-arc oxidation in alkaline electrolyte to obtain aluminum ytterbium micro-arc oxidation film.The performance of the oxide film is tested and analyzed by XRD,SEM,EDS and electrochemical workstation.Discuss the influence of different Yb content in the oxide film and the oxidation time,oxidation voltage,and additives on the performance of the oxide film when preparing the micro-arc oxide film.The results show that when the Yb content is 0.29%,the surface of the micro-arc oxidation film is denser and the corrosion resistance is relatively good;when the oxidation voltage is220 V for 10 minutes,the corrosion resistance of the micro-arc oxidation film achieves the optimal value;When the additive is sodium fluoride,the corrosion resistance of the micro-arc oxidation film is the best.