Study On Preparation Of Al-Ti Alloy By Electrodeposition

Ti element has fineness effect on Al and Al alloy.And Ti can effectively improve the strength,wear resistance,workability,castability and thermal conductivity of the alloy.And ir reduce the expansion coefficient.In the preparation method of the Al-Ti alloy,traditional preparation methods require heating and high energy consumption.In the method Al-Ti alloy has the disadvantages of composition segregation,hydrogen evolution and high cost.Electrodeposition can effectively avoid these shortcomings.Moreover,it has the advantages that the prepared plating layer has high purity and the substrate is not limited by the shape.Electrodeposition is commonly used to prepare metal coatings with special functions.It can effectively improve the properties of metal surfaces.Such as oxidation resistance,corrosion resistance,electrical conductivity and non-magnetic properties.The AlCl₃-LiAlH₄-C₆H₆-THF organic solvent system has a mature preparation process and high current efficiency.And the organic solvent system does not affect the mechanical properties of the matrix material during the preparation of the Al-Ti alloy coating layer.And it does not produce hydrogen and corrosive products.The prepared coating is of high purity.Based on the research of electrodeposition preparation of Al-Ti alloy by scientific researchers in various countries.In the AlCl₃-LiAlH₄-C₆H₆-THF organic solvent system,there are two different ways of introducing Ti ions.Al-Ti alloy coating was prepared by using Ti wire as anode electrodeposition and Al-Ti alloy plating by adding anhydrous TiCl₄.First the cyclic voltammetry and chronoamperometry were used to study the processes of electrodeposited Al-Ti alloy.And then the conductivity of electrolyte in electrodeposited Al-Ti alloy was studied by alternating current impedance method.Then study on the effects of different factors on the quality of Al-Ti alloy coating.Finally study on the morphology,grain size and Ti content of electrodeposited Al-Ti alloy coating by SEM scanning electron microscopy,EDS energy spectrum analysis and X-ray diffraction.Preparation of Al-Ti alloy coating were studied by adjusting the influencing factors?Ti ion introduction mode,current density,deposition time,anhydrous AlCl₃ addition amount and anhydrous TiCl4 addition amount?.Cyclic voltammetry studies have shown that the reduction process of Al ions in the AlCl₃-LiAlH₄-C₆H₆-THF system is Al³⁺?Al.The reduction process of Ti ions in lCl₃-LiAlH₄-C₆H₆-THF-Ti system is Ti⁴⁺?Ti³⁺?Ti²⁺?Ti.There is a single step of Al³⁺?Al before co-depositing the Al-Ti alloy.The reduction reaction of Ti ions in the AlCl₃-LiAlH₄-C₆H₆-THF-TiCl₄ system is Ti⁴⁺?Ti³⁺?Ti²⁺?Ti.The deposition difficulty of Al becomes larger and larger.The electrochemical window widens in turn.The conductivity of the electrolyte was analyzed under Ti ion introduction by alternating current impedance methodand different amounts of anhydrous TiCl₄.It is found that the AlCl₃-LiAlH₄-C₆H₆-THF-TiCl₄ system has the best electrical conductivity.When Al-Ti alloy was prepared by using Ti wire as anode electrodeposition,the main components of the coating were Al and AlTi.The grain size of the Al-Ti alloy coating decreases with increasing current density.The amount of Ti increases as the current density increases.The Ti content of Al-Ti alloy coating increases first and then decreases with the increase of deposition time.The optimum deposition time range is2³h.The Ti content of Al-Ti alloy coating increases first and then decreases with the increase of anhydrous AlCl₃.The optimum amount of anhydrous AlCl₃ is 7.80⁸.01g.When the Al-Ti alloy coating was prepared by electrodeposition with anhydrous TiCl4.The main components of the coating were AlTi3,Al5Ti2 and Al3Ti.The grain size of Al-Ti alloy coating decreases with the increase of current density.And the Ti content increases with the addition of anhydrous TiCl4.When the amount of anhydrous TiCl4 is2.85g?anhydrous AlCl3 and The molar ratio of anhydrous TiCl4 was 4:1?.The amount of Ti contained in the Al-Ti alloy coating layer was 42.87wt%by weight.The grain size of the Al-Ti alloy coating decreases with increasing current density.The amount of Ti increases as the current density increases.Within the scope of the study,the optimum current density was 37.00mA/cm².Alcoating grains have angular edges and large crystal grains.The Al coating layer refined by the Ti is elongated and the crystal grains are small.The Al-Ti alloy coating has a spherical shape and a small crystal grain.