Percolation Effects in the Mechanical Properties of Granular Ni-A12O3 thin films

Abstract

ABSTRACTThe mechanical properties of sputtered Ni-Al2O3 granular thin films were investigated by low load microharaness testing. It was found that the microhardness of these films displayed a percolation threshold at a nickel volume fraction of about 0.6, below which the hardness is greatly enhanced. This behavior is qualitatively similar to the electrical and magnetic properties of these types of films. A percolation threshold in hardness can be understood as due to a change in the mechanism for plastic deformation.