Nanotechnology Lect.9

Nanocoatings
Nanocoatings are a type of nanocomposite. The layer thickness of a nanocoating is
usually 1–100 nm. Nanocomposite films include multilayer thinfilms, in which the
phases are separated along the thickness of the film, or granular films, in which the
different phases are distributed within each plane of the film (Figure 28).
Figure 28: Schematic of possible structures for nanostructured coatings: left: multilayered microstructure
(e.g. TiN/TiC) for nanocomposite coatings; right: homogeneous nanostructured coating (e.g. NiCoCrAlY
alloy)
Nanocoatings make it possible to change the properties of some materials, for
example to change the transmission of visible and IR radiation in glass, or to
introduce new properties such as ?self-cleaning‘ effects. Here, this first type of
nanocoating will be discussed under the umbrella term ?responsive nanocoatings‘.
Another important area of application of nanocoatings is tribological coatings.
Tribology is the science and technology of interacting surfaces in relative motion.
Tribological properties include friction, lubrication and wear. Tribological coatings
are those coatings that are applied to the surface of a component in order to control
its friction and wear. In this area, the term ?thin films‘ is often used as an
alternative to nanocoatings — due to the fact that this is an area of innovation that
has existed for many years and has now reached the nanoscale.