FeB-Ni Cemented Carbide Was Prepared By Electroless Plating And Electrospark Sintering

The traditional cemented carbide WC-Co system combines the characteristics of high hardness,high wear resistance,good toughness,etc.,and is widely used in the field of cutting tools.However,it currently has problems such as insufficient resources and high cost.FeB is expected to become a candidate material for the hard phase due to its advantages such as higher hardness and wear resistance.The combination of FeB and Ni can not only improve the brittleness of FeB,but also can improve the corrosion resistance of the alloy.In this project,FeB-Ni cemented carbide was prepared by powder electroless nickel plating and spark plasma sintering,and the best powder electroless nickel plating and sintering process was obtained.The surface morphology,crystal structure and nickel content of the composite powder and sintered body were tested by SEM,XRD,ICP and other equipment.In addition,the mechanical properties of the sintered body were measured by means of microhardness tester,electrochemical workstation,DSC,the corrosion resistance and oxidation resistance were tested.The formula of electroless nickel plating solution I(purchased plating solution)obtained in the experiment is:defoamer concentration 1 ml/L,powder loading capacity3 g/L.The process parameters of electroless nickel plating bath I are:electroless plating time 15 min,temperature 40?,bath pH=9±0.1,stirring speed 200 r/min.The formula of electroless nickel plating bath II(self-prepared bath)is:main salt nickel sulfate concentration 32 g/L,reducing agent sodium borohydride concentration 1.2 g/L,complexing agent sodium citrate 100 g/L,buffering agent Borax 6 g/L,active agent sodium lauryl sulfate 0.004 g/L,stabilizer thiourea 0.004 g/L,powder loading capacity 3g/L.The process parameters of electroless nickel plating bath II are:electroless plating time 30 min,temperature 55?,bath pH=12±0.1,stirring speed 200 r/min.In these two kinds of baths,a uniform nickel plating layer was obtained.The electroless plating bath I has a faster deposition speed,but the electroless bath II has a wider temperature range.Finally,the FeB-Ni composite powder was sintered,and the process parameters were obtained:sintering temperature 1000?,holding time 10 min,initial sintering pressure 20MPa,reaction sintering pressure 50 MPa.The results of the study found that the density of FeB-20 Ni cemented carbide at 1000?is about 98.12%,the hardness value is 1257.2 HV,the toughness value is 9.38 MPa·m^-1/2,also obtain good corrosion resistance and oxidation resistance.