| The amorphous alloys represented by nickel-based alloy have high strength,high hardness,high wear resistance,good corrosion resistance,excellent magnetic and electrical properties,which can be used in many fields such as aerospace,automobile manufacturing,medical devices,electronic communication.Currently,electrodeposition can be used to prepare most amorphous alloys,which has some advantages such as bath stability,cost and equipment operation.However,there are always some shortcomings in amorphous alloys prepared by electrodeposition,such as surface defects,pitting corrosion,porosity,excessive internal stress,difficult maintenance of bath during heating and low processing rate at room temperature.Therefore,the introduction of multi-field recombination in the electrodeposition system has become an important method to solve the deficiency of single electrodeposition.There are two forming conditions for preparing amorphous alloys by electrodeposition:(1)When electrodeposition,the cathode needs to have a large over-potential,which makes the nucleation rate increase to effectively generate small and numerous crystal nuclei;(2)Cathode hydrogen evolution will hinder the regular arrangement of atoms,however,accompanied with excessive internal stress and hydrogen permeation.In this paper,the laser irradiation and magnetic field are introduced into the electrodeposition system.The main research contents and achievements are as follows:1.The mechanism of multi-field(laser,magnetic field and electric field)composite preparation of amorphous alloys was studied.(1)The electro-crystallization process of metals and alloys,and the mechanisms of co-deposition and induced co-deposition were studied;(2)Influence of heat effect,force effect,convection and stirring on deposition process by laser irradiation;(3)Influence of magneto-hydrodynamic effect,magnetic effect and magnetization effect on concentration polarization,growth rate and grain orientation during electrodeposition.2.Effect of different laser parameters on the preparation of amorphous Ni-P coating by electrodeposition was studied,and the surface quality,internal structure and properties were tested.Laser can improve the cathode over-potential and provide favorable conditions for the formation of small size and large number of crystal nuclei.Micro-zone stirring can also remove the bubbles that hinder the regular arrangement of atoms precipitated by cathode in time,so as to improve the surface quality,internal stress,corrosion resistance and wear resistance of the coating.When the laser single pulse energy is 16 ?J,the frequency is 1 MHz and the scanning rate is 3000 mm/s,the comprehensive performance of Ni-P coating is optimal.3.A magnetic field was introduced based on the system of laser enhanced electrodeposition.The effect of laser single pulse energy and magnetic field intensity on surface quality,internal structure and properties of amorphous Ni-Fe-P coating was studied.Laser can form micro-region stirring to facilitate Fe reduction and reduce the activation energy required for the reaction to facilitate the Ni reduction.Magnetic fluid(MHD)effect can inhibit concentration polarization,and the magnetic and magnetization effects generated by magnetic field on electrode and paramagnetic particles affect the growth direction of crystal nucleus and form anisotropy,thereby improving the properties and internal stress of the coating.Under the condition of other parameters are constant,when the laser single pulse energy is 16?J and magnetic field intensity is 15 m T,the comprehensive performance of the coating is optimal.In summary,the introduction of multi-energy fields(laser,magnetic field)in electrodeposition system can effectively improve the shortcomings of electrodeposition to prepare amorphous Ni-P/Ni-Fe-P alloy,which is of great significance to prepare amorphous alloys with excellent properties. |
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