Research On Wear Resistant Coatings Of Ni Base Alloy Reinforced By WC By Plasma Cladding

Under the condition of soft abrasive wear,nickel base alloy coating can show higher wear resistance,which has some heat resistance,corrosion resistance and oxidation resistance,but the wear resistance of the coating under the condition of hard abrasive and complex abrasive wear is lower.In order to improve the wear resistance of Ni base alloy coating under the condition of hard abrasive wear,Ni base alloy Ni25,Ni45 and Ni60 are selected as the cladding matrix materials,cast tungsten carbide and single-crystal tungsten carbide are used as reinforcement phases,and plasma cladding technology is used to prepare Ni base tungsten carbide cladding on Q235 steel plate.Mainly for the preparation process of Ni base tungsten carbide cladding layer,the appropriate addition amount of tungsten carbide,and no The influence of WC on the microstructure and properties of Ni based alloy cladding layer was studied.The microstructure and properties of the cladding layer were characterized and tested by optical microscope,scanning electron microscope,energy dispersive spectrometer,X-ray diffraction,three-dimensional microscope,hardness tester,abrasive wear tester and other related methods.The influence of the structure change of the cladding layer on the wear resistance of the cladding layer is analyzed.The results show that when 60% mass fraction of cast tungsten carbide is added to Ni45 alloy powder,the optimized preparation process parameters of nickel-based tungsten carbide cladding layer are: plasma cladding current 120 A,powder feeding speed 25g/min,ion gas flow 4L/min.In the Ni45 alloy powder,50%,60% and 70% cast tungsten carbide are added respectively.The results show that: because the density of the reinforcing phase tungsten carbide is much higher than that of the nickel-based alloy,the cast tungsten carbide particles appear delamination in the cladding layer.With the increase in the amount of tungsten carbide,the hard phase in the cladding layer increases,and the protective effect on the nickel matrix is enhanced.However,when the amount of tungsten carbide is 70%,the bonding degree of tungsten carbide and the nickel matrix is weaker.Under the hard abrasive wear,part of the tungsten carbide and the nickel matrix are cut out by the abrasive,which cannot effectively protect the nickel matrix.Under the two abrasive abrasive wear conditions,the nickel-based cladding layer with60% mass fraction of cast tungsten carbide showed the best wear resistance.Because tungsten carbide dissolves in the cladding layer,part of the tungsten carbide is smaller in size after dissolution,and it cannot effectively prevent the abrasive from cutting the nickel matrix under the rough abrasive wear.The abrasive wears the nickel matrix and tungsten carbide more,so the cladding The abrasion loss of the layer under the coarse abrasive is significantly increased compared with the fine abrasive,and the wear resistance is significantly decreased.In order to further study the strengthening effect of cast tungsten carbide on different nickel base alloys,60% of cast tungsten carbide was added to Ni25,Ni45 and Ni60 Alloy Powders respectively.The results show that the dissolution of WC particles in Ni25 alloy cladding layer is relatively small,and they are well combined with nickel matrix.There is a large amount of chromium in Ni45 and Ni60 Alloy,which promotes the dissolution of WC during the cladding process,and a large number of brittle secondary carbides are formed in the cladding layer,which seriously affects the wear resistance of the cladding layer.Therefore,under the abrasion of two kinds of abrasive particles,Ni25 alloy cladding layer The layer with cast WC shows the best wear resistance.In order to study the strengthening effect of WC on Ni based alloy,60% WC was added into Ni25,Ni45 and Ni60 alloy powder respectively.The results show that the dissolution of WC is very small in the cladding layer of Ni base alloy,and the combination with the Ni base is weak.After the Ni base is cut by hard abrasive in the process of wear,the exposed WC particles lack the effective support of the base and are pulled out by the hard abrasive as a whole,which weakens the protection of the Ni base and makes the wear resistance of the cladding layer more serious than that of the cast WC Down.Because there is no carbide forming element chromium in Ni25 alloy,the volume fraction of WC in the cladding layer is larger,and the wear resistance is higher than that of Ni45 and Ni60.