Functional and Decorative Coatings onto Metal Strips Deposited by Plasma-Activated High-Rate Electron beam Physical Vapor Deposition (EbPVD)

摘要

A great variety of coating materials can be obtained by methods of physical vapor deposition (PVD). Nearly all coating materials composed of metals, alloys and compounds can be realized. For instance high-quality oxide or nitride coatings can be produced by plasma-activated electron beam evaporation. The paper gives an introduction to the latest developments in relevant PVD technologies and presents some results for decorative and functional purposes. Titanium dioxide thin films were deposited on stainless steel strips. The process is based on generation of titanium vapor and chemical reaction in a pure low-pressure oxygen atmosphere. Crystalline titanium dioxide thin films, especially layers with predominantly anatase phase, exhibit super-hydrophilic and photo-catalytic activities after exposure to ultraviolet light. Refractive index of titanium dioxide coatings was measured in the range of 2.3 to 2.5. This relatively high refractive index causes strong color effects based on thin film interference. Interesting decorative effects were also obtained by nitride or carbide coatings. Such compounds have a high hardness and a characteristic color. Gold-colored and well-adherent titanium nitride coatings with a micro-hardness up to 30 GPa could be deposited onto stainless steel strip by plasma-activated electron beam evaporation. It could be shown that scratch resistance of steel surface was remarkably increased by deposition of thin fused quartz layers. These transparent coatings were prepared by evaporation of silicon dioxide.