6. TiN-PVD film
With the development of multilayer coating, the most popular method concentrates on utilising the PVD-arc technique to deposite the TiN thin film on the thick RPS substrate. This type of substrate consists of a TiN dispersion of a Ti matrix’s internal. Generally, an essential characteristic of the multilayer coating is the bonding of TiN to Ti/TiN substrates, mainly depending on the morphology and composition of the TiN substrates.
There are some experimental results indicated an extraordinary phenomenon (Casadei F,2006), the TiN-PVD films are able to fill the surface porosity of the Ti/TiN-RPS films. By contrast with the general process of PVD position, the PVD film and the RPS film will produce chemical reactions, which can make relatively large donation to the gradient properties and the excellent adhesion of the multilayer systems.
Additionally, it is worth to notice that the RPS plus PVD-arc coating will induce an nonstop damage by the increasing imposed load.