Research On Process Test Of Textured Surface Prepared By Electrodeposition And Laser

With the increasing shortage of global resources and energy,improving the surface properties of materials in the actual production process so as to prolong the service life of materials is of great significance to the strategic goal of sustainable development in China.However,changing the material of the parts or the whole equipment to achieve the purpose of surface strengthening is not economical and desirable.In addition,the key components of many high-end machines have different requirements on the material matrix and surface properties.Surface engineering technology can quickly and efficiently endow superior performance to material surfaces at low energy consumption and cost through physical,chemical and mechanical processes.Compared with a single surface engineering technology,the application of multiple technologies to the surface of the material will bring more excellent performance.In this paper,electrodeposition technique is combined with laser surface texture technique.The electrodeposited Ni-Co-Si₃N₄ nanocomposite coating was prepared on the surface of 45 steel to investigate the effect of electrodeposition process parameters on the surface morphology and properties of the nanocomposite coating.The microstructures were processed on the nanocomposite coating by microsecond pulsed laser to investigate the morphology evolution law of the microstructures.The laser-textured region was prepared on the surface of nano-composite coating to investigate the effect of microstructure morphology and surface density on the performance of laser-textured nano-composite coating surface.It provides reference basis for choosing different process parameters according to different processing requirements in actual production.The main research contents of this paper are as follows:1.Study on the influence of electrodeposition process parameters on Ni-Co-Si₃N₄ nano-composite coatings.The single factor method was used to prepare different Ni-Co-Si3N4nanocomposite coatings by changing the electrodeposition temperature,current density and nanoparticle concentration,and the morphology of the nanocomposite coatings was observed.The element content,phase structure,roughness,hardness,friction coefficient and static contact angle were measured to discusse the effect of the electrodeposition process parameters on the performance of nanocomposite coatings.The test results show that:The electrodeposition temperature,current density and nanoparticle concentration have a certain degree of influence on the surface properties of the materials.When the electrodeposition temperature changes from 40℃to 70℃,the current density changes from 0.5 A/dm² to2.0 A/dm²,and the nanoparticle concentration changes from 4 g/L to 10 g/L,the coating properties will be firstly improved and then decreased.In the range of experimental parameters in this paper,when the electrodeposition temperature is 60℃,the current density is 1.5 A/dm²,and the concentration of nanoparticles is 8 g/L,the Ni-Co-Si₃N₄ nano-composite coating can obtain the best performance.2.Study on the influence of laser processing parameters on the microstructure of nanocomposite coating surface.By using microsecond pulse laser processing device,the laser energy density,pulse width and pulse number were changed for processing microstructure of Ni-Co-Si₃N₄ nano-composite coating.And then the surface microstructure of the samples was observed and characterized.The influence of the machining parameter on the microstructure morphology was analyzed,and the formation mechanism of different morphologies was discussed.The test results show that:The output energy density,pulse width and pulse number of single laser pulse all have a certain degree of influence on the surface microstructure morphology of nanocomposite coating.The laser interacts with Ni-Co-Si₃N₄ composite coating,and the coating formed four typical morphologies:spherical-cap shaped bump,W-shaped crater,crater and crater with double concentric holes.As pulse energy density increased,the surface microstructure changed from spherical-cap shaped bump to crater with double concentric holes.As pulse width increased,the surface microstructure changed from crater to spherical-cap shaped bump.Besides,as pulse number increased,the depth and edge height of the surface microstructure increased.The corresponding relationship between laser parameters and the microstructure of Ni-Co-Si3N4composite coating surface was formed by experiments.3.Preparation and performance study of Ni-Co-Si₃N₄ nano-composite coating by laser textured surface.16 kinds of laser-textured Ni-Co-Si₃N₄ nanocomposite coatings were prepared by using a microsecond laser processing device with 4 kinds of microstructure morphology and 4 kinds of surface densities.The effects of microstructure morphology and surface density on the surface properties of laser-textured nanocomposite coatings were investigated by observing morphology and characterizing the roughness,hardness,friction coefficient,wear mark depth and static contact Angle.The test results show that:In the range of this experiment,as the microstructure changes from W-shaped crater to crater with double concentric holes,the microhardness of the edge of the microstructure increases and the microhardness of the blank area between the microstructures has no obvious change.The change of surface density does not cause the change of microhardness of the edge of microstructure and the blank area between microstructure.As the microstructure changes from W-shaped crater to crater with double concentric holes,the friction coefficient on the sample surface decreases first and then increases,and the wear mark depth also decreases first and then increases.The sample surface has the best friction and wear performance when the microstructure of the sample surface is deep crater morphology.The sample surface density for obtaining the best friction and wear performance is different with different microstructures.The laser-textured surface can obtain the highest static contact angle in the deep crate microstructure morphology under 4 surface densities,and can obtain the highest static contact angle at the surface density of 30%for all the 4 kinds of microstructures.The best wettability is obtained by laser texturing the crater surface at 30%surface density.