Study On Preparation And Friction Properties Of Low Pressure Cold Sprayed High Aluminium Bronze Coatings

Wear is one of the main forms of mechanical damage and failure.The use of spray technology?coating technology?to repair worn parts can extend the life of the parts and save the company considerable energy and costs.The low-pressure cold sprayed layer has the characteristics of tight coatingstructure,lowporosity,andsimplepreparationprocess.Low-pressure cold spray powders and substrates are also widely used,and the directional repair capability has significant advantages in industrial production.High-aluminum bronze is a new type of hypereutectoid copper alloy,which has excellent antifriction and wear resistance.The powder coating also has good wear resistance and friction reduction properties.If low-temperaturecold-sprayingtechnologyisusedtoprepare high-aluminum bronze alloy powder on the surface of easily worn parts(such as Cr₁₂Mo V alloy steel rolls),the wear resistance of the parts can be improved,and the service life can be extended.In this paper,the high-alumina bronze powder was modified by temperature pretreatment and mixed with hard phase Al₂O₃.The modified powder was used as a low pressure cold spray powder and sprayed on a Cr₁₂Mo V alloy steel substrate to prepare a coating.The hardness,thickness and bond strength of the coating were tested using an HV-1000 hardness tester,Shimadzu AG-10TA universal material testing machine,and vernier caliper.The field emission scanning electron microscope observes and analyzes the coating,stretching the surface and the profile.The effects of Al₂O₃ content and pretreatment temperature on the coating properties were studied.Then select the method with better heat treatment temperature,treat the high-aluminum bronze powder,and mix it with different Al₂O₃powders to prepare a low-pressure cold spray coating on the Cr₁₂Mo V alloy steel substrate.The HT-1000 friction tester was used to test the friction and wearpropertiesofthecoating.Fieldemissionscanningelectron microscopes,XRD and 5000DX surface roughness analyzers were used to examine friction and wear surfaces,wear components and wear surface roughness.The role of Al₂O₃ in the friction process was studied,and the influence of its content on the friction properties of the coating was analyzed.The results show that:1.The modified high-aluminum bronze powder material can be used to prepare low-pressure cold spray coating.2.When the preheating temperature is 400°C,the content of Al₂O₃ in the powder is 29%,and the mechanical properties of the coating are the best.3.The effect of the content of Al₂O₃ on the mechanical properties of the coating is:as the content of Al₂O₃ in the powder increases,the coating The mechanical properties of the first increase and then reduce the trend;4.Al₂O₃ content on the coating's influence on the mechanical properties of the layer is:With the increase of Al₂O₃ content in the powder material,the friction coefficient of the coating The amount of wear and wear decreased first and then increased.