Nanocrystalline materials and coatings

Abstract

In recent years, near-nano (submicron) and nanostructured materials have attracted increasingly more attention from the materials community. Nanocrystalline materials are characterized by a microstructural length or grain size of up to about 100 nm. Materials having grain size of $0.1 to 0.3 mm are classified as submicron materials. Nanocrystalline materials exhibit various shapes or forms, and possess unique chemical, physical or mechanical properties. When the grain size is below a critical value ($10-20 nm), more than 50 vol.% of atoms is associated with grain boundaries or interfacial boundaries. In this respect, dislocation pile-ups cannot form, and the Hall-Petch relationship for conventional coarse-grained materials is no longer valid. Therefore, grain boundaries play a major role in the deformation of nanocrystalline materials. Nanocrystalline materials exhibit creep and super plasticity at lower temperatures than conventional micro-grained counterparts. Similarly, plastic deformation of nanocrystalline coatings is considered to be associated with grain boundary sliding assisted by grain boundary diffusion or rotation. In this review paper, current developments in fabrication, microstructure, physical and mechanical properties of nanocrystalline materials and coatings will be addressed. Particular attention is paid to the properties of transition metal nitride nanocrystalline films formed by ion beam assisted deposition process. #

Effect of TiO 2 addition on the microstructure and nanomechanical properties of Al 2 O 3 Suspension Plasma Sprayed coatings

“…In particular, nanostuctured coatings are expected to provide several industries with enhanced components leading to better properties and longer lifetime [7][8][9].…”

Deposition of Al2O3-TiO2 Nanostructured Powders by Atmospheric Plasma Spraying

“…Nanostructured materials represent an enhanced version of their conventional counterparts (Ref 1, 2) and usually exhibiting better performances (Ref [3][4][5]. Bulk nanomaterials are being extensively studied but also nanostructured coatings on conventional materials are investigated as they have the potential of providing several industries with novel materials with improved properties and prolonged lifetime .…”

Are Sintered Silver Joints Ready for Use as Interconnect Material in Microelectronic Packaging?

“…Compared to the literature concerning nanocrystalline materials, 75,76 similar studies that relate the density and porosity (including pore shapes) to the elastic modulus for sintered Ag joints are lacking. One common technique for characterizing these pores is to consider the ratio of the annular flaw size to the pore radius.…”