Effects of various fillers on the sliding wear of polymer composites

Short fibre reinforced polymer composites are nowadays used in numerous tribological applications. In spite of this fact, new developments are still under way to explore other fields of application for these materials and to tailor their properties for more extreme loading conditions. The references given at the end of this review describe some of these developments. In the present overview further approaches in designing polymeric composites in order to operate under low friction and low wear against steel counterparts are described. A particular emphasis is focused on special filler (including nanoparticle) reinforced thermoplastics and thermosets. Especially, the influence of particle size and filler contents on the wear performance is summarised. In some of the cases, an integration of traditional fillers with inorganic nanoparticles is introduced and presents an optimal effect. Furthermore, some new steps towards the development of functionally graded tribo-materials are illustrated.     

Block Copolymer Nanocomposites: Perspectives for Tailored Functional Materials

Heterogeneous materials in which the characteristic length scale of the filler material is in the nanometer range—i.e., nanocomposites—is currently one of the fastest growing areas of materials research. Polymer nanocomposites have expanded beyond the original scope of polymer–nanocrystal dispersions for refractive‐index tuning or clay‐filled homopolymers primarily pursued for mechanical reinforcement, to include a wide range of applications. This article highlights recent research efforts in the field of structure formation in block copolymer‐based nanocomposite materials, and points out opportunities for novel materials based on inclusion of different types of nanoparticles. The use of block copolymers instead of homopolymers as the matrix is shown to afford opportunities for controlling the spatial and orientational distribution of the nanoelements. This, in turn, allows much more sophisticated tailoring of the overall properties of the composite material.     

Mechanical Behavior of Multilayered Nanoscale Metal‐Ceramic Composites

Single and multilayered structures at nano‐length scale are very attractive materials due to their high strength, toughness, and wear resistance relative to conventional laminated composites. In this study, single layered Al, SiC, and multilayered Al/SiC composites were synthesized by DC/RF magnetron sputtering. The microstructure of the multilayered structures was characterized by scanning electron microscopy (SEM). The elastic and plastic behavior of single and multilayered materials was investigated by nanoindentation and tensile testing. For nanoindentation, an analytical model was employed to subtract the contribution of the Si substrate, in order to extract the true modulus of the films. Finite element simulations were employed to confirm the analytical predictions and to investigate the anisotropic elastic behavior of the multilayered composite. It was concluded that while indentation provides reasonable Young's modulus and hardness values in monolithic layers, it does not provide the true modulus of the multilayered materials because of their inherent anisotropy.