Sliding wear study of ion-beam mixing NiMo multilayer films on steel

Abstract

Ion-beam mixing (IBM) process was used to prepare NiMo multilayer film. Monolayer films of nickel or molybdenum films and NiMo double-layer film were also prepared in a similar manner. Microhardness of the multilayer film was investigated. Tribological properties of the deposited films were systematically measured by a precise measurement apparatus of dynamical friction under unlubricated sliding conditions. The rubbing surfaces and wear debris were examined using scanning electron microscopy (SEM). The test results showed that the microhardness of NiMo multilayer film had been improved greatly compared with the monolayer films. The wear rates of the multilayer film were lower than that of substrate, monolayer and double-layer films under low load, and its friction coefficient became more stable than that of monolayer films. The improvement of tribological characteristics of the multilayer film was attributed to its layer structure. The interfaces between layers in the multilayer film improved the microhardness of multilayer film. Consequently, the wear rate decreased. The wear mechanism of NiMo multilayer film was fatigue and delamination wear.