Design And Synthesis Of TiAlN/Al₂O₃Nanoscale Multilayered Coatings By Magnetron Sputtering Techueque

TiAlN/Al2O3multilayers were synthesized on alumina substrates and Si substrates by magnetron sputtering. The layered and multilayer structure of the TiAlN/Al2O3multilayers were investigated by a glancing angle X-ray diffraction (XRD) and scanning electron microscopy(SEM). The crystalline and multilayer structures of the multilayers were determined by X-ray diffractometer (XRD). A nanoindenter was used to evaluate the hardness, the elastic modulus and scratch scan of the multilayers. The chemical bonding was investigated by a X-ray Photoelectron Spectroscopy (XPS). Residual stress generated during the coating growth process were calculated according to the curvature measured using an XP-2profiler.The influence of modulation periods and ratios, Ar/N2ratios, work pressure and substrate bias on structure and properties of the TiAlN/Al2O3multilayers was discussed. Meanwhile, we have also measure oxidation resistance and the thermal stability of TiAlN/Al2O3multilayers.The change on hardness and elastic modulus of TiAlN/Al2O3multilayers was dependent on modulation periods and modulation ratios. With increasing A, the hardness and elastic modulus of the multilayers decreased before increase. Meanwhile, Hardness and elastic modulus of the TiAlN/Al2O3multilayers increased firstly and then decreases with decreasing tTiAlN:tAl2O3. The maximum hardness is about36.6GPa, when the multilayers have the modulation period (10.4nm) and modulation ratio (10:1).The influence of work pressure, Ar/N2ratios and substrate bias on structure and properties of the TiAlN/Al2O3multilayers was obvious. Optimal deposit condition was obtained. The hardness and elastic modulus of the TiAlN/Al2O3multilayers were up to maximum value (39.8GPa and546GPa) when Ar/N2ratio, work pressure and substrate bias were18:1,0.4Pa and-140V, respectively. All TiAlN/Al2O3multilayers have appeared crystallized with orientations in the TiAlN (111). In different condition, TiAlN/Al2O3multilayers showed different crystal structure, such as TiAlN(200), TiAlN(220), TiAlN(222), TiAlN(311), AlN(111) and so on.In order to measure the thermal stability and oxidation resistance, TiAlN/Al2O3 multilayers were heated to500℃and700℃in vacuum and air. Annealing is that the temperature of the samples increased to the desired temperature (500℃or700℃) in specific surroundings and maintaining the desired temperature for30min. Heating rate was2℃/min. Subsequently, the samples were cooled down to room temperament at a rate of2℃/min. Compared with as-deposited multilayers, the annealed multilayers exhibited increased hardness. The structure also showed good high temperature stability.We have obtained the optimal technologic parameter to synthesis TiAIN/Al2O3multilayers that had the high hardness, elastic modulus, well adhesion, thermal stability and oxidation resistance and so on. Therefore, TiAlN/Al2O3multilayers have great potential in application of industry.