Preparation And Properties Of Ni-cBN Composite Coating

The blade tip and seal coating of various types of aero-engine in service in our country are grinding,and the wear size of blade tip is too large,which seriously affects the engine dynamic performance,so it is urgent to use wear-resistant coating under high temperature condition.According to the requirements of high-performance wear-resistant and corrosionresistant coatings for the key components of aero-engine turbine blades such as blade tip and seal grate at high temperature,the coating design was carried out,and cBN particles were selected as the strengthening phase.The Ni-cBN composite coating was prepared by electrodeposition of nickel aminosulfonate with low stress as binder.The cBN particles were suspended by stirring electrodeposition solution.During electrodeposition,nickel particles were deposited into the coating,nickel and cBN particles were co-deposited.Find the suitable surfactant,reduce the interfacial tension between particles and solution,the interfacial tension between matrix and solution,reduce the retention time of hydrogen bubble at the solid interface,and increase the density and interfacial bonding strength of the composite coating.The influence of particle concentration in solution and stirring intensity on composite content were studied,and the sand coating method was used to further improve the composite content of coating.The effects of cBN content and particle size on hardness,friction and wear properties of coating at room temperature and high temperature were studied.A pure nickel layer of about 5 ?m was deposited on the surface of TC4,DZ125,then the composite coating was prepared to improve the adhesion of the coating.The pre-treatment technology of TC4 and DZ125 was studied.The main findings are as follows: Compared with sodium dodecyl sulfate,cetylammoNium bromide and polyethylene glycol,it can be found that the composite coating with higher content can be obtained by plating in the bath contaiNing sodium dodecyl sulfate and the coating quality is better.It is suitable for the wetting agent of cBN in the system of Nickel aminosulfonate.The composite plating process of Ni-cBN in Nickel sulfamic acid system was studied.The particle sizes were 0.5 ?m,3 ~ 5 ?m and 10 ?m.When the stirring speed was 320 rmin and the concentration of particles in the plating solution was 70 g/L,the particle size was 0.5 ?m,3 ~ 5 ?m,and the particle size was 0.5 ?m,3 ~ 5 ?m,respectively.The composite amounts of 10 ?m,77.38 v% and 75.85 v% were 36.05%,77.38 v% and 75.85 v%.respectively.The content of cBN in the coating was further increased by sand coating.The composite coating content of cBN with 3 ~ 5 ?m particle size was 82.30% and 85.37% respectively by sand coating method.Compared with sodium dodecyl sulfate,cetylammonium bromide and polyethylene glycol,it can be found that a higher composite coating can be obtained by plating in the bath containing sodium dodecyl sulfate,and the coating quality is better.It is suitable for the wetting agent of cBN in the system of nickel aminosulfonate.The composite plating process of Ni-cBN in nickel sulfamic acid system was studied.The particle sizes were 0.5 ? m,3 ~ 5 ?m and 10 ?m.When the stirring speed was 320 rmin and the concentration of particles in the plating solution was 70g/l,the particle size was 0.5 ? m,3 ~ 5 ?m,and the particle size was 0.5 ?m,3 ~ 5 ?m,respectively.The composite amounts of 10 ?m were 36.05 v%,77.38 v% and 75.85 v%,respectively.The content of cBN in the coating was further increased by sand coating method.The particle size of 3 ~ 5 ?m cBN composite coating prepared by sand coating method was 82.30 v%,and 10 ? m was up to 85.37 v%.The study of TC4,DZ125 pretreatment process shows that the coating with qualified adhesion can be obtained by secondary leaching of zinc,leaching of nickel and hydrogenation of three kinds of pre-treatment of TC4,and the adhesion of the coating is the best after the treatment of secondary leaching of zinc.The adhesion force of the coating was calculated by scratch formula after pickling on the surface of 94 MPa.DZ125,and the adhesion of the coating prepared by heat treatment was increased by 144.6% Compared with the untreated coating at 90 MPa,.The adhesion of the coating was better than that of the untreated coating.