| In the broad research field of multilayered films, devoted to study more about hard/hard multilayered films. Because there is a big problem such as residual stress in this type of multilayered films, the film can easily be detached from the based body, thereby limiting its practical application. Based on the actual production in the field of industrial application, the design of soft/hard multilayer system has been the trend of The Times. Al2O3coatings are concerned widely because of its high strength, high hardness and good abrasion resistance. However, because of its intrinsic brittleness, it often breaks due to brittle fracture in the process of fraction, seriously affected the ware life of Al2O3coatings. So Al/Al2O3soft/hard alternate multilayered films were designed in this article, expect to improve their applied potential in the automotive industry, tooling industry and aerospace or in the other fields.In this paper, DC and RF magnetron sputtering method were adopted to prepare Al film and Al2O3film, through orthogonal test, determine the preparation conditions of Al film and Al2O3film respectively, ultimately alternating deposited AI/Al2O3multilayered films with modulation period for80nm,100nm,120nm, modulation ratio for0.25,0.5,1,2,3. And the structure of these multilayered films were characterized by modern testing techniques such as XRD, SEM, AFM and XPS, observed the cross-section shape and surface topography, combined with the Nano Indentation and Multi-functional Tester for Material Surface Properties to test the mechanical properties and friction and wear properties of Al/Al2O3multilayered films. The results show that soft phase Al layer is fcc-centered cubic structure, while hard phase Al2O3layer is amorphous characteristic. Under the same modulation period, the peak of Al (111) broadens with the decrease of modulation ratio, grain size decreases gradually, show that Al phase has ultrafine crystalline structre. Under the same modulation ratio, with the decrease of modulation period, the peak angle of Al (111) offset to the high angle, and it stays away from the standard peak gradually. Cross section morphology observation shows that multilayered films have good layer structure. AFM test results show that the surface layer Al2O3is a typical island mode of growth. Under the same period, the surface roughness of Al2O3layer increase with the decrease of modulation ratio, make the smoothness of the surface improved. Under the same modulation ratio, with the increase of the modulation period, the surface roughness of Al2O3layer decreases, increase the surface smoothness of the film. XPS results show that the stoichiometric of Al2O3layer is close to the theoretical cacilation value.Performance testing results show that the bonding force of Al/Al2O3multilayered films with modulation ratio for0.5is the best under the same modulation period, under the same modulation ratio, the bonding force is the best for multilayered films with the modulation period forlOOnm. For the same modulation period, hardness and elastic modulus show a trend of increasment with the decrease of modulation ratio. For the same modulation ratio, hardness and elastic modulus show a trend of increasment with the decrease of modulation period. Under the same modulation period, exception for multilayered films with the modulation ratio for0.25, there have a linear relationship between the hardness of multilayered films and the reciprocal of the square root of the thickness of metal layer, and approximate with Hall-Patch relationship. Under the same modulation period, the friction coefficient decrease with the decrease of modulation ratio, wear resistance is improved. Under the same modulation ratio, the friction coefficient decrease with the decrease of modulation period. Though comprehensive analysis, multilayered film which modulation period is100nm, modulation ratio is0.25has the best comprehensive performance, the value of its bonding force is30.40N, the value of hardness, elastic modulus and friction coefficient is10.18GPa,178.28GPa,0.119respectively. |
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