Microstructure And Properties Of Laser Cladding New Designed Ni-based Coatings With Corrosion Resistant And Wear Resistant

Fretting wear and corrision can cause serious damage on surface of mechanical equipment components,making it completely ineffective and unable to continue to serve.The failed parts can be repaired by adding a layer of material with better surface characteristics(ie,a more corrosion-resistant surface coating)to the surface of the mechanical equipment component.The key component of the short-stress line mill is typical mechanical equipment used for corrosive and wear conditions,and its failure will cause the entire mill to be scrapped.Furthermore,laser remanufacturing technology,a well-known and powerful repair engineering process,enables manufacture the new low-friction materials to repair failed components.Ni-based alloys are widely used in laser repair and remanufacturing of failed parts under various corrosive and wear conditions due to their good corrosion and wear resistance.At present,the Ni-based wear-resistant alloy Ni60 used in the industry has good wear resistance,but has poor corrosion resistance and formability,and has many cracks,which is difficult to meet the repair requirements of parts after extensive corrosion and wear.To solve the problems in remanufacturing of failed key parts of short stress wire mill serving in fretting wear and corrosion conditions,Ni16Cr5Fe4.5Si6B3W-CeO₂ alloy powder,a new Nickel-based alloy with higher corrosion resistance and wear resistance used in laser remanufacturing was designed by JMatpro based on the phase diagrams theory,and a new NiCrFeSiBW-CeO₂ composite coating was successfully cladded on 45#steel under different laser energy density 166 J/mm2,125 J/mm2,100 J/mm2 and 83 J/mm2.The microstructure and evolution of the alloy composite coating were studied by OM,SEM,XRD,EPMA,EBSD,TEM,and its wear-resistance and corrosion-resistance properties were characterized using wear tester and the electrochemical workstation,respectively.The results show that the NiCrFeWSiB-CeO₂ composite coating prepared under the optimized laser energy density of 100 J/mm2 has no crack and pore defects.The hardness of the coating prepared under the optimized energy density(100 J/mm2)is 561 HV0.1,the average friction coefficient is 0.44,the Ecorr is improved to-0.1738 V,and the Icorr is 1.81×10-7 A/mm2 The structure of the coating are composed of y-Ni and some fine in-situ generated compound particles.In-situ generated B₃Cr₅,CrB₄,(Cr,Ni)₃C₂,Cr₇C₃,W₃Cr₁₂Si₅ and(Fe,Ni)₅Si₃ compound particles reinforcing wear properties of the coatings,and the B₃Cr₅,CrB₄ and W₃Cr₁₂Si₅ compound particles enhancing the corrosion resistance.Furthermore,a 180 mm × 75 mm × 1.5 mm repair scale was prepared by printing with a YAG laser,and the alloy powder can repair the failure surface of the rack column in a large area with a reasonable ratio of 1:10.This new Ni-based alloy coating not only has good wear-resistance but also has great corrosion-resistance.