Study On Properties Of Fe-ni Alloy Prepared By Laser And Magnetic Field Assisted Electro-deposition

As an important soft magnetic material,iron-nickel alloy is widely used in the electronics industry,communication industry and other fields due to its excellent soft magnetic properties and mechanical properties.With the rapid development of science and technology,the demand for high-performance iron-nickel alloys is increasing rapidly,so many researchers have focused on the research of new iron-nickel alloy preparation processes.Electrodeposition technology is an important way to prepare iron-nickel alloys due to its advantages of simple process,low cost,high controllability,and so on.However,the coating has defects such as pinhole,pit,crack,and slow processing rate,which limit the further improvement of iron-nickel alloy material properties.Multi-energy field composite processing technology is an effective means to improve the performance of materials,while laser and magnetic field,as non-contact processing,can significantly improve the performance of the prepared metal coating when combined with electrodeposition technology.In this dissertation,the method of preparing iron-nickel alloy by introducing laser and magnetic field into electrodeposition technology was proposed.First,a laser assisted electrodeposition experiment platform was built to study the effect of laser parameters on the surface quality,structure and properties of iron-nickel alloy coating.Secondly,a magnetic field-laser-assisted electrodeposition test platform was built on the basis of laser action,and the effect of increasing magnetic field on the coating surface quality,microstructure and properties of the coatings was analyzed.Finally,the effect of magnetic field direction on the preparation of Fe-Ni alloy was studied under the condition of no laser irradiation.The main research contents are as follows:1.The mechanism of electrodeposition assisted by laser and magnetic field was studied.The basic theory of metal ion electrodeposition was analyzed,including the conditions of alloy co-deposition and the electrode process of metal ion reaction.The effects of thermal effects such as temperature rise and micro-stirring on the improvement of electrodeposition and the impact of force effects on ion reduction,crystallization and hydrogen evolution which generated by laser irradiation were discussed.The effect of magnetohydrodynamic effects and magnetic effect on the electrodeposition process and the effect of magnetization force on the crystallization process were analyzed and summarized.2.The preparation of Fe-Ni alloy coating by laser-assisted electrodeposition was studied.The effects of laser parameters on the surface morphology,microstructure,microhardness,corrosion resistance,tensile properties and wear resistance of the alloy coating was studied.The study found that,laser irradiation could significantly improve the surface quality of the coating,reduce the grain size,and enhance the performance of the coating,moreover the iron content in the coating was increased by laser irradiation,but the grain structure of the coating was still face-centered cubic crystal.The control variable method was used to study the laser parameters.The properties of alloy coating reached the best when the single pulse energy was 15.0 ?J;the properties tended to be stable when the frequency was greater than 2.0 MHz;the deposited layer had the best performance when the scanning line spacing was 30 ?m;the performance of the coating was best when the scanning speed was 4000 mm/s.3.The effect of magnetic field on the surface quality,microstructure,hardness,corrosion resistance,tensile properties and wear resistance of the coating was studied on the basis of laser-assisted electrodeposition.The result showed that,the introduced magnetic field could further enhance the performance of the alloy coating.And changing the magnetic field intensity,the properties of the alloy coating showed a trend of increased first and then decreased.When the magnetic field intensity was 15 mT,the properties were best.When the magnetic field was too large,the solution would be over-stirred,and the surface of the coating would have obvious flow pattern,which would reduce the surface quality and properties of the coating.4.The effect of magnetic field direction on the preparation of alloy coatings was studied without laser irradiation.The experimental results show that both magnetic field directions produce macroscopic magnetohydrodynamic effects.The solution produced the horizontally flow when the transverse magnetic field was applied,and the rotational flow when the vertical magnetic field was applied.The alloy coatings prepared in the two magnetic fields had excellent surface quality and properties,but the properties of the coatings in the transverse magnetic field were slightly better than those in the vertical magnetic field.The results of this study showed that laser and magnetic fields have effcts on the mass transfer process,electron transfer process and crystallization process,which could significantly improve the properties of iron-nickel alloys.The results of this study have important reference significance for the preparation of high-performance Fe-Ni alloys.