Nanoindentation and nanotribological behavior of Fe-N/Ti-N multilayers with different thickness of Fe-N layers

Fe-N/Ti-N magnetic multilayers with different thickness of Fe-N layers were deposited on Si (1 1 1) wafer by using magnetron sputtering technique. For comparison, Fe-N and Ti-N thin films were also prepared under the same conditions. Microhardness and reduced modulus of the multilayer were measured by using a nanoindenter with a diamond tip in conjunction with an atomic force microscope (AFM). Microfriction and microscratch tests were performed by using a capacitance transducer with a conical diamond tip used in conjunction with the AFM. The results show that the thickness of Fe-N layer has effects on microhardness and microtribological properties of the multilayer. The microhardness of the multilayer increases with the contact depth. For an applied normal force less than 1250 μN, the hardness of the multilayer decreases with the thickness of Fe-N layer, but the reduced modulus of the multilayer does not change much with the thickness of Fe-N layer. Friction coefficient and microscratch scar depth of the multilayer increase with the thickness of Fe-N layer. The results indicate that the structure of Fe-N/Ti-N periodic multilayer has higher mechanical properties than single Fe-N film. Among all the samples studied, Fe-N (5 nm)/Ti-N (2 nm) multilayer has the highest microhardness, lowest friction coefficient and highest microwear resistance.