SUPERHARDNESS EFFECT IN AU NI MULTILAYERS

The presence of an enhanced hardness, that is, a 'superhardness effect ', is found as a behavior parallel to the supermodulus effect in Au/Ni multilayer structures. The submicron-thick Au/Ni coatings are prepare d by magnetron sputter deposition. A microindenter is used to measure load as a function of indentation depth. An increase in hardness is me asured as the Au/Ni layer pair spacing decreases. A local maximum in h ardness occurs for samples with layer pairs consisting of 4-6 atomic p lanes of each metal component.