Mechanical Properties and Deformation Behavior of Ni Nanodot-Patterned Surfaces

Abstract

Surface nano-texturing has attracted great attention due to its potential for significantly reducing adhesion and friction in micro-electro-mechanical systems (MEMS) and nano-electro-mechanical systems (NEMS). However, severe deformation of the nano-textures was also observed during tribological testing of nano-textured surfaces (NTSs). Therefore, understanding the mechanical properties and deformation behavior of nano-textures and nano-textured surfaces is of critical importance to the development of durable NTSs for MEMS/NEMS applications. Here, we review our recent work in understanding the mechanical properties and deformation behavior of Ni nanodot-patterned surfaces (NDPSs) on silicon substrates. First, the benefit of nanoscale surface-texturing for MEMS/NEMS application and the size-dependent mechanical properties of nanostructures are introduced. Second, various experimental techniques are described, which include methods of fabricating and characterizing Ni NDPSs as well as studying the mechanical properties and deformation behavior of NDPSs using nanoindentation. Third, methods of determining mechanical properties of Ni nanodots from nanoindentation experiments are presented. Fourth, a multi-asperity contact model for studying the nanoindentation deformation behavior of the Ni NDPSs is described. Fifth, simulation results from the multi-asperity contact model are compared to nanoindentation experiments and validated by the experimental results. Finally, the model is used to study effects of substrate, surface roughness, elastic modulus, and yield strength.