Abstract

Advanced hard coating concepts like multilayer coatings, multicomponent solution hardened layer materials, new metastable layer materials, nanocrystalline layer materials or superlattice films become increasingly important for wear protection under extreme and complex loads. Among these advanced coatings, the multilayer concepts seems to be the most versatile and promising with respect to properties and performance in almost all the fields of application. Nanostructured multilayer coatings exhibit outstanding physical, mechanical, and chemical properties, opening a range of new applications in high technologies. These outstanding properties are due to the interface and nanoscale effects associated with structural peculiarities of nanostructured coatings where the volume fraction of the interfacial phase is extremely high, and crystalline size does not exceed 100 nm. Multilayers are extensively used in semiconductor, optical, and metallurgy industries and are becoming of increasing importance in areas such as magnetic recording, superconductors, and, lately, wear- and corrosion-protective coatings.

Titanium and its alloys are widely applied in various fields of human activity including medicine. This is still the most commonly used material for surgical tools and biological devices, like implants and endoprosthesis. The main advantages of titanium-based materials in medical applications is their good biocompatibility, low density, high level of mechanical properties and corrosion resistance. However, one of the important features limiting the application of this material in medicine is its relatively low wear resistance, leading to the release of the material elements into the surrounding cells or tissues in a biological environment. Most processes proceeding in the human body occur at surfaces and interfaces of implant material. The main effective method for overcoming the above mentioned limitation therefore concerns a surface modification, which would improve biological function, with a hard coating. Nowadays, the possibility to modify and control the surface wettability of biological materials has attracted significant scientific and technological interest. For biological systems the nature of hydrophobic and hydration forces plays a key role on the mediation of solute adsorption and cell adhesion.