Electrodeposition And Properties Of Aluminum Based Alloy

Aluminum alloy has the characteristics of light weight,excellent ductility,decoration,corrosion resistance,and rich reserves.It is an ideal construction protection material and it is widely used in aerospace,marine transportation,automobile lightweight and other fields.And aluminum alloy has a broad development prospect.The theoretical hydrogen storage capacity of Al based magnesium alloy is high,which is widely used in hydrogen storage materials.In order to make aluminum alloy be used more widely,it is necessary to prepare ultra-fine pure alloy.Electrodeposition is one of the effective methods to obtain high purity alloy.In the experiment of electrodeposition of aluminum base alloy,the microstructure and composition of the alloy can be controlled by controlling the parameters of electrodeposition process and Chemicals composition of electrodeposition bath to prepare high-purity ultra-fine aluminum alloy.AlCl3-LiAlH4 organic solvent system is the first system used in aluminum electrolysis,which can be carried out at room temperature.It has the characteristics of energy saving,simple operation and no adverse effect on the matrix.Based on the research of electrodeposition of Al and Al Mg alloys at home and abroad,AlLa and AlMgLa alloys have been successfully prepared by DC electrodeposition in AlCl₃-LiAlH₄-benzene-THF organic solvent using two electrode system.The corrosion resistance of AlLa and AlMg La alloy coating was studied by polarization curve method.The coating morphology and the mass fraction of La and Mg in AlLa and AlMgLa alloy were examined by SEM,EDS,XRD.Aluminum lanthanum and aluminum magnesium lanthanum alloy coatings were successfully prepared by direct current electrodeposition.The effects of current density,deposition time,lanthanum chloride content,experimental environment and conditions on the composition,morphology,crystal structure and the mass fraction of effective components in the coatings were studied.The experimental results show that when the molar ratio of aluminum chloride and lanthanum chloride is 10:1,the current density is 10mA/cm²,and the deposition time is180 minutes,the morphology of the deposited aluminum lanthanum coating is granular crystal,the alloy grain is small,the coating is fine and flat,the combination with the substrate is good,the coating does not crack,and the mass fraction of lanthanum in the prepared aluminum lanthanum alloy is high,which is 7.33wt%.When the molar ratio of aluminum chloride,magnesium chloride and lanthanum chloride is 10:1:1,the current density is 20mA/cm²,and the deposition time is 60 minutes,the grain size of the deposited aluminum magnesium lanthanum alloy is the smallest,the average grain size is 2-3μm,and the minimum grain size can reach 500 nm,and it is expected to prepare aluminum magnesium lanthanum alloy with grain size of about 100 nm or less;the coating is compact and flat,with good combination with the substrate;The highest content of magnesium in the coating is 2.76wt%,and the highest content of lanthanum is 1.19wt%.The results show that the average grain size of AlMgLa alloy is smaller than that of AlLa alloy.Through calculation of polarization resistance value,it is found that when the mass fraction of lanthanum is high,the polarization resistance value is large,and the corrosion resistance of aluminum lanthanum alloy coating is good.For AlMgLa alloy coating,the smaller the grains and the higher the polarization resistance,the better the corrosion resistance of AlMgLa alloy coating.Comparing the polarization resistance of AlMgLa alloy with that of AlMgLa alloy,it is found that the polarization resistance of AlMgLa alloy is relatively high,and the corrosion resistance of AlMgLa alloy is better.This is because the grains of AlMgLa alloy are relatively small and dense,and it is easier to form passive rust film,which plays a good role in protecting AlMgLa alloy.