Study On Preparation,Microstructure And Properties Of MAX Phase Reinforced Ni-based Superalloy Coating

Strict environment in the field of aerospace and gas turbines,a higher requirement,especially the frictional wear problem in the wide temperature of the material represented by the nickel-based high temperature alloy,anti-wear and high temperature resistance Its significant characteristics,conventional solid lubricants have been difficult to adapt to harsh usage environments,and the current solution is mainly to achieve continuous lubrication of a wide temperature domain by adding different lubricants from low temperatures to high temperatures,or by forming a compound or the like Oxidation.The membrane or other high temperature lubricant acts as a synergistic lubrication.For the traditional lubricant,the traditional lubricant continuously lubricated in high temperature and high speed conditions,this study uses a new type of three-membered compound Cr₂AlC(MAX phase)with excellent characteristics,design and prepared different Cr₂AlC.The content of the Ni5Al/Cr₂AlC composite coating was studied in detail the effect of Cr₂AlC on the tissue and performance of nickel-based high temperature alloy,and the tough integration of nickel-based high temperature alloy and continuous lubrication of the wide temperature domain were discussed.(1)This article first prepared Cr₂AlC powder material by powder metallurgy,with a purity of 99.5%,and prepared nickel-based superalloy coatings with different Cr₂AlC contents by plasma spraying,and studied its mechanical properties,mechanical properties and high temperature resistance.Oxidation performance.The results showed that the microhardness value increased from 141.47HV_0.2(0wt.%Cr₂AlC)to 214.24HV_0.2(30wt.%Cr₂AlC),an increase of 51.4%;the high temperature oxidation resistance test showed that the addition of Cr₂AlC would increase the coating Anti-oxidation performance,NC₁coating has the best effect,NC₂(20wt.%Cr₂AlC)and NC₃(30wt.%Cr₂AlC)have decreased oxidation resistance due to internal microcracks;three-point bending test study of the coating under 1300N pressure It was found that with the increase of Cr₂AlC,the mechanical properties of the coating at room temperature deteriorated,resulting in longitudinal cracks.(2)The effect of the addition of Cr₂AlC on the tribological properties of the composite coating in a wide temperature range(room temperature to 800°C)was studied.The results show that the NC₁(10wt.%Cr₂AlC)composite coating has the lowest friction coefficient and wear rate.The friction coefficients of NC₁and NC₀(0wt.%Cr₂AlC)have basically the same changing law,decreasing at 200?and slightly increasing at 400?,and then the NC₁coating continues to decline,thanks to the wear resistance of the surface composite oxide film Reduce the wear effect,the fatigue wear of the wear machine gradually becomes slightly adhesive wear;the friction coefficient of NC₀gradually increases,and the oxidation wear and brittle fracture of the wear machine gradually become plastic deformation;NC₂(20wt.%Cr₂AlC)and NC₃(30wt.%Cr₂AlC)The coefficient of friction of the coating decreases as the temperature increases,and the wear machine gradually becomes abrasive wear due to fatigue wear.The four sets of coating wear rates have shown the trend of decline before rising.(3)After the tribological performance test of the 800?isothermal heat treatment coating,it is found that the wear rate is greatly reduced due to the increase of the coating hardness.The NC₁coating is due to the hard phase The pinning effect and the smooth surface of the enamel layer have good friction properties.The friction and wear of the composite coating in the seawater corrosive environment is simulated.The study shows that the wear rate of the four groups of coatings is an order of magnitude lower than that under dry friction conditions.The addition of Cr₂AlC will significantly improve the tribological properties of the coating.With the increase of Cr₂AlC With the increase,the passivation layer of the coating is gradually complete and smooth,indicating that Cr₂AlC has certain electrochemical corrosion resistance.