| According to the incomplete statistics,at present,about 30%-40%of the energy is consumed in various forms of friction in the world.For the friction system,the wear resistance is our first consideration,and the friction materials play a decisive role in the friction sysyem,At present,nations are increasing investment on materials of high hardness,high wear resistance and low friction coefficient,which can be applied to various rotating and recipr-ocating friction conditions.Research on AlMgB14 material has been nearly 50 years.AlMgBl4 material crystal structure consists of four B12 icosahedra and Al,Mg and B atoms exist between the icosahedral units.TiB2dispersed in AlMgB 14 matrix,can greatly improve the mechanical properties of materials,Al-Mg-Ti-B coating has high hardness,low friction coefficient,low density and high thermal stability,and has wide application prospect in friction system.The effect of bias on the composition,structure,roughness and hardness of Al-Mg-Ti-B coatings prepared by DC magnetron sputtering is lack of systematic study,The friction behavior and wear mechanism of Al-Mg-Ti-B coating under oil lubrication conditions are not clear.In this work,the Al-Mg-Ti-B target required for DC magnetron sputtering was prepared by mechanical mixing and hot-pressing.By SEM,EDX,XRD means to characterize,It is found that the prepared Al-Mg-Ti-B target has a dense structure,good crystallinity and little impurity content,which can meet the requirements of DC magnetron sputtering target.Al-Mg-Ti-B coatings were prepared by DC magnetron sputtering.The Al-Mg-Ti-B coatings were prepared by using the different bias voltages with single crystal Si as substrate.Analysis the Composition,roughness,hardness and other properties of Al-Mg-Ti-B coating.The AES spectra show that the Al-Mg-Ti-B coating is homogeneous and has the same composition from the coating surface to the inside.XRD results show that the bias voltage does not affect the crystallization of Al-Mg-Ti-B coating,which is amorphous structure.Using XPS to analyze the composition and chemical state of the coating,increasing the bias voltage is beneficial to reduce the content of C O impurity in the coating,the B-B bond content in the coating increases,thus increasing the hardness of the coating,while the bias to promote the oxidation of metal Ti;SEM showed that the bias increased the density of Al-Mg-Ti-B coating and the column structure gradually disappeared.The surface roughness of the coating increases first and then decreases with the increase of the bias voltage.The increase of bias will increase the fracture toughness and mechanical properties of the coating.However,with the increase of the bias voltage,the residual stress of the coating will increase,and the bonding ability with the substrate will be weakened.The effect of bias voltage on the tribological behavior of Al-Mg-Ti-B coating prepared by DC magnetron sputtering was also systematically studied.Different Al-Mg-Ti-B coatings were prepared by DC magnetron sputtering changing the different bias voltage with bearing steel as the substrate.Using oil lubrication(PAO+MoDTC)ball-type rotating friction test,Under the condition of oil-lubricated room temperature,the friction coefficient of Al-Mg-Ti-B coating can reach the ultra-low friction coefficient of 0.04,May be due to form a MoS2 friction film in the friction test process,in contact with the grinding ball on the grinding surface.As the bias increases,the coefficient of friction increases.The morphological analysis and composition analysis of the wear marks show that the wear rate of the coating during the friction process is extremely low,Did not form a clear wear marks and the emergence of peeling phenomenon in the coating with the ball on the surface contact,The increase in the content of Fe is due to the fact that the Fe element is transferred from the surface of the grinding ball to the surface of the coating during the friction test. |
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