| The corrosion resistance of carbon steel can be improved by adding nickel in steel,but its expensive price makes a substantial increase in the cost of material production,nickel containing carbon steel / carbon steel gradient materials can effectively solve the contradiction.Some basic problems of preparing nickel containing carbon steel / carbon steel graded materials by electro deposition diffusion method were studied.Firstly,the molten salt deposition method for preparing nickel containing carbon steel / carbon steel gradient materials in Na Cl-KCl-Na F-Ni O molten salt system with carbon steel as the cathode,pure nickel as the anode.The results showed that the molten salt electro deposition diffusion method can prepare the gradient material,but the gradient layer is thin,and the component distribution is not easy to control.In the condition of the composition of the molten salt as x Na Cl=0.36,x KCl=0.36,x Na F=0.25,x Ni O=0.02,deposition temperature of 750℃,time is 50 min,the current density for about3030 m A/cm2,bidirectional pulse as current waveform,can prepare better containing nickel carbon /carbon gradient materials.The Fe-Ni diffusion couple was prepared by the water solution deposition method,and the gradient material can be prepsred by diffusion annealing method.The results show that the diffusion mechanism of nickel in carbon steel is in line with the vacancy diffusion mechanism and the atomic exchange mechanism.The relationship between nickel content,the time and the depth and the relationship between diffusion coefficient and temperature is obtained,the diffusion activation energy is Q=5.2159×104J/mol.In the range of the content of nickel in the 0~100% the corrosion resistance of gradient material increased firstly and then decreased,the best corrosion resistance of nickel content is about 81.426%,at the same time,the corrosion potential is-0.005 V.In the case of nickel content is certain,the corrosion resistance increases with increasing temperature. |
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