MICROSTRUCTURES AND MICRO-HARDNESS OF TiN/AlON NANOMULTILAYERS SYNTHESIZED BY REACTIVE MAGNETRON SPUTTERING

Ti and Al_2O_3 targets are used to prepare a series of TiN/AlON nanomultilayers in the gas mixture of Ar and N_2 with reactive magnetron sputtering method.The formation conditions of AlON and the effects of thickness of AlON on microstructures and mechanical properties of the multilayers are evaluated and characterized by EDS,XRD,HRTEM and nanoindentation.The in- vestigations show that O atom in Al_2O_3 will be partially replaced by N atom when sputtering Al_2O_3 target in the gas mixture of Ar and N_2,forming amorphous AlON.In TiN/AlON nanomultilayers, when thickness of AlON is less than 0.6 nm,AlON,due to the template effect of TiN crystal layer, is forced to crystallize and grow epitaxially on TiN,and the multilayers begin to show superhard- hess effect with a highest HV value of 40.5 GPa.With further increase of the thickness of AlON,its growth mode changes from crystal to amorphous,therefore the epitaxial structure of multilayeres was destroyed and the hardness of multilayers decreased.