Research On Electronical Explosion Spray Deposition In Protective Atmosphere

With the development and innovation of surface modification technology,in order to obtain different special properties on the surface of metal materials,such as wear resistance and corrosion resistance,surface modification technology has higher and higher requirements for various process methods.As a new method in surface modification treatment,the wire electrical explosion spray deposition method has many obvious advantages compared with the traditional spray deposition method.In this paper,based on the gas discharge method,the current is introduced into the wire to explode.The method of wire electrical explosion spray deposition in protective atmosphere is proposed.The deposition layer of aluminum wire on the arc surface after electrical explosion is explored and studied.The optimum process parameters for the depositionlayer of aluminum wire by electrical spray are determined.In this paper,a set of wire electrical explosion spray deposition test equipment for protective atmosphere was developed.The equipment is mainly composed of high-voltage generating device H.V.,carrying hub and its moving mechanism,base transmission mechanism,electrode and pressing mechanism.The wire is fed to the two fixed electrodes through the wire hub and its moving mechanism,and the high voltage generating device H.V.introduces the pulse current into the wire by gas discharge to cause electric explosion,and deposits under the action of the wire hub restraining groove.Forming a deposition layer on the substrate.The electrical explosion spray deposition test was carried out using the wire electric explosion spray deposition test apparatus in the above-mentioned protective atmosphere.The test material was made of high-purity aluminum wire.The initial voltage of the capacitor was 8kV,9kV,10kV,and the diameter of the aluminum wire was 0.3mm,0.4mm,0.5mm,and the spray deposition distance was 35mm.The cross section characteristics were observed and analyzed by SEM,energy dispersive spectrometer?EDS?,and the bonding strength and hardness of the deposition layer were tested.Finally,the theoretical model of the wire electrical explosion in the protective atmosphere was proposed.The test mainly obtained the following results:the width of the deposition layer after electric explosion was 4mm-4.5mm,the deposition layer was symmetrical on both sides of the center line of the substrate,and the thickness was the highest in the middle,and the thickness of the deposition layer gradually became thinner on both sides.After three depositions,the thickness of the deposition layer has tended to be uniform throughout the cylindrical surface.Observed the cross section of the deposition layer obtained under various parameters,when the diameter of the aluminum wire is 0.5mm and the charging voltage of the capacitor is 8kV,there are many holes in the deposition layer,and the size of the hole is about 10?m;when the diameter of the aluminum wire is 0.3mm,and the charging voltage of the capacitor is 9kV,a deposition layer having a small hole ratio and a uniform cross sectional thickness can be obtained;however,when the aluminum wire diameter is 0.3mm and the charging voltage is 10kV,the hole ratio in the cross section suddenly increases.For samples under other parameters,the higher the voltage applied to the ends of the wire,the smaller the wire diameter,that is,the higher the energy deposition in the wire,the smaller the particles in the surface of the deposition layer and the cross section,and the smaller the porosity in the cross section.The Vickers-hardness test of the hardness of the deposition layer under the test parameters was carried out.It was found that when the diameter of the aluminum wire was 0.3mm and the charging voltage of the capacitor was 9kV,the hardness of the deposition layer was the highest,the average value reached 171.9HV_0.1.When the diameter of aluminum wire 0.5mm and a capacitor charging voltage of 8kV,the lowest average value is 133.7HV_0.1.By using the indentation test to analyze the bond strength of the deposition layers obtained under different parameters,no obvious cracks were found around the deposition layer laminate marks,and compared with the standard indentation map,the strength of the deposited layer was HF-1.