The Study Of Ni-Co-P Alloy Pulse Plating Technology And Performance

Because of stable plating solution,easily control and the preparation of the excellent performance of alloy plating.Dc plating nickel base alloy was become the hot research.Despite direct current deposition of alloy can improve crystallization,the plating hardness,corrosion resistance,But through the long-term,lots of research,scholars found The efficacy of direct current deposition has been close to the limit.Choose a new technique of alloy electrodeposition plating become inevitable.Using pulse technology to replace the traditional DC deposition is an effective and foreseeable way.In the paper,Based on the Ni-Co-P alloy plating,Using DC electroplating,single pulse electroplating,periodic reversal pulse plating technology,Ni-Co-P alloy plating was prepared.corrosion resistance of Ni-Co-P alloy plating was studied by electrochemical test,The hardness of alloy plating was tested by hardness tester,The microstructure of alloy plating was analyzed by SEM.the elements composition and phase composition of the alloy plating were analyzed by EDS and XRD.Studies show that Ni-Co-P DC alloy plating optimum process is Nickel sulfate:250 g/L,Nickel sulfate: 250 g/L,nickel chloride: 40g/L,cobalt sulfate: 25g/L,Sodium hypophosphite: 4 g/L,boric acid: 35 g/L,SDS: 0.1 g/L,the density of plating: 5 a/dm2,temperature: 50 ?,pH: 3.5 to 4.5,t: 30 min.The performance of the alloy plaing is best,hardness is 629 HV(200gf),the corrosion current is 9.56 ?A,linear polarization resistance of 4377 ohm.Ni-Co-P alloy single pulse plating optimum process is Nickel sulfate: 250 g/L,nickel chloride: 40g/L,cobalt sulfate: 25g/L,Sodium hypophosphite: 4g/L,boric acid: 35 g/L,SDS: 0.1 g/L,the density of plating: 5 A/dm2,temperature:50 ?,pH: 3.5 to 4.5,t: 30 min Positive duty ratio is 80%,the positive average current density is 4 A/dm2,pulse frequency of 1 KHz.The hardness of Ni-Co-P alloy single pulse plating is 675 HV(50gf),the corrosion current is 17.9 ?A,linear polarization resistance of 2407 ohm.Crystallinity is 69.23%,the particle diameter of 20.92 nm.Ni-Co-P alloy cycle reverse pulse electroplating optimum process is Nickel sulfate: 250g/L,nickel chloride: 40g/L,cobalt sulfate: 25g/L,Sodium hypophosphite: 4 g/L,boric acid: 35 g/L,SDS: 0.1 g/L,the density of plating: 5 A/dm2,temperature: 50 ?,pH: 3.5to 4.5,t: 30 min Positive duty ratio is 80%,the positive average current density is 4A/dm2,pulse frequency of 1 KHz,negative duty ratio is 8%,negative current density is0.3 A/dm2.The hardness of Ni-Co-P cycle reverse pulse electroplating is 523 HV(50gf),the corrosion current is 15.8 ?A,linear polarization resistance of 2535 ohm.crystallinity is 91.64%,the particle diameter of 22.76 nm.The optimum heat treatment process is heat treatment temperature is 300 ?,the heat treatment time is 120 min.The hardness of Ni-Co-P alloy cycle reverse pulse electroplating which under the optimum heat treatment process is 708 HV(50gf),the corrosion current is 5.10 ?A,linear polarization resistance of 3818 ohm.crystallinity is95.53%,the particle diameter of 27.07 nm.The best cerium nitrate content of Ni-Co-P alloy pulse plating is 0.3 g/L,The hardness of Ni-Co-P alloy cycle reverse pulse electroplating which the best cerium nitrate content is 0.3 g/L is 502 HV(50gf),crystallinity is 91.74%.