Study On Diamond Barrel Plating Technology With Rotating Electrode And Its Application

As well know,diamond is the hardest substance in the nature.Compared with ordinary abrasive tools,use diamond as a cutting material made of diamond abrasive tool have the advantages of high sharpness,strong processing ability,good shape,surface accuracy retention and high reliability.They are widely used in automobile manufacturing,aerospace,precision parts,optical instruments and many other fields.Using surface coating technology to wrap a layer of metal coating on the diamond surface can effectively improve the bonding strength between diamond particles and bond,and improve the phenomenon of diamond surface oxidation and graphitization caused by high ambient temperature.At present,the commonly plating technologies include electroless plating,electroplating,magnetron sputtering,atomic layer deposition and so on.However,there are still have some problems in the current plating methods,such as difficulty in coating fine-grained diamond,missed coating,thin coating,uneven coating and low efficiency.Therefore,exploration is more efficient,and the more uniform diamond surface plating technology of coating is the goal that has been pursuing.In this project,a diamond barrel plating technology based on rotating electrode is proposed,which makes the cathode rotate in the barrel plating process,so as to increase the dispersing ability of abrasive particles and the uniform conductivity of electricity between particles,so as to improve the efficiency of diamond plating and improve the uneven coating.In this project,the mechanism,device and basic technology of barrel plating were systematically studied.At the same time,the metallization method and technology of diamond surface before barrel plating were also studied.The results show that a complete process system of nickel plating on diamond surface is formed,which has certain significance for promoting the development of diamond grinding material plating technology.The specific research work is as follows:1.The research on the mechanism of rotary electrode rolling plating.The contact model of diamond particles and rotating electrodes and the mechanical model of diamond abrasive particles during the plating process are established.The dynamics and kinematics analysis of grain size abrasive particles are obtained,and the power of abrasive particles in the plating fluid is obtained.Learning equation,revealing the basic laws of rolling mechanism and main factors affecting the rotating electrode.2.Design and manufacture of rotating electrode roll test devices.According to the mechanism of barrel plating,a barrel plating test device was designed and manufactured,in which the electrode can rotate and the bath bottle can rotate.The key process factors such as the rotation speed of the bath bottle,the rotation speed and the direction of the rotating electrode can be controlled,which lays a foundation for the experimental research of barrel plating with rotating electrode.At the same time,it can also be used as a prototype for popularization and application.3.Diamond surface metallization.The experimental study of nickel and silver on diamond surface was carried out by chemical plating.The best combination of the single factor experiment is:temperature is 90℃,p H=4.7,coating time 1.5 h,stirring speed 200 r/min,diamond loading capacity 10 g/l,activator mass fraction 30%,diamond weight gain rate 24.2%and Ni content of 61.25%.The best combination of chemical silver plating technology is:temperature is 20℃,ph=9.0,plating time 2.0 h,sirring speed 200 r/min,diamond loading capacity 10 g/l,activator concentration should be 4 g/l,the diamond weight gain rate is 16.6%,and Ag content of coating is 54.68%.4.Selection and optimization of roll plating plating ingredients.The coating comprehensively performs experimental study on the plating layer of the amino sulfonate,nickel sulfate,sulfate,nickel sulfate-nickel chloride,and nickel sulfate,Based on the analysis of the experimental results,the sulfamate plating solution is the best plating solution for diamond barrel plating.The optimized bath composition and process are as follows:Ni Cl₄·6H₂O（70～90）g/L,Ni（NH₂SO₃）₂·4H₂O（300～550）g/L,H₃BO₃（30～45）g/L;when the current density is 2 A/dm²,temperature is 50℃,p H=4.5,the best coating performance can be obtained,and the hardness,porosity can be improved,HV 257 and 27.8μm/h were the optimal values.5.Experimental study on the basic technology of rolling nickel plating on diamond surface with rotating electrode.The effects of diamond size,rolling current,electrode rotation speed and cathode rotor diameter on the surface of diamonds were studied by orthogonal trial.The results indicate that the main relationship between the factors is:rolling current>Cathode speed>Diamond size>Cathode rotor diameter.Taking about diamonds having a particle size of 70/80 as an example,he rolling current 4A,the cathode rotor 20 r/min,the cathode rotor is 30 mm and the electrode and the vapor are rotated to the optimum process conditions.Under the process conditions,the diamond surface plating is uniform,and the coating deposition rate is 2.42 g/h.At the same time,the coating experiment of rotating electrode and common electrode was carried out.The results show that the effective contact area of rotating electrode on abrasive grains is greatly increased,and more Abrasives can be coated at one time,which greatly improves the efficiency and economy of diamond barrel plating.By analyzing the micro morphology of the coating,it is found that the coating by rotating electrode barrel plating is more delicate and smooth.6.Research on nickel plating of fine-grained diamond grains by rotary electrode barrel plating.On the basis of the preliminary work,the rotating electrode plating technology of fine-grained diamond was carried out.According to the mechanism of rotating electrode barrel plating,the relationship between the rotating speed of the bath bottle and the rotating speed of the electrode,as well as the effect on the weight gain rate of diamond and the surface morphology of diamond were investigated.The experimental results show that:for fine-grained diamond powder,the weight gain rate decreases with the decrease of particle size;with the increase of particle size,the suspensibility of the particles increases,and the rotating speed of the rotating electrode should be increased;The rotating electrode roller plating can detect about 5μm at the particle size range of the galvous particles.