Nanoindentation and microtribological behavior of Fe–N/Ti–N multilayers with different thickness of Ti–N layers

Fe–N/Ti–N multilayers with different thickness of Ti–N layers were deposited on Si(1 1 1) wafer by using magnetron-sputtering technique. For comparison, Fe–N and Ti–N single-layered films were prepared under the same condition. The microhardness and the reduced modulus of the multilayer were measured by using a nanoindentor with a diamond tip (Berkovich) 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. For applied normal force <1500 μN, the hardness of the multilayer increases with the thickness of Ti–N layer, but the reduced modulus of the multilayer does not change much with the thickness of Ti–N layer. The trend of friction coefficient of the multilayer does not change with the thickness of Ti–N layer, but the depth of microscratch scar decreases with the thickness of Ti–N layer. The results indicate that the Fe–N/Ti–N periodic multilayer has better mechanical properties than Fe–N single-layered film. Among all the samples studied, Fe–N (10 nm)/Ti–N (10 nm) multilayer has the highest hardness and the highest microscratch resistance.