Oxidfilme

Oxidfilme, or oxide film, are thin layers of oxide that form on a material surface as a result of oxidation. They are common on metals, semiconductors and ceramics and can arise naturally in air or water, or be produced deliberately by processes such as anodizing, thermal oxidation or chemical passivation.

Formation occurs when oxygen from the environment reacts with the substrate material. Thickness ranges from a few angstroms for native films to tens or hundreds of nanometers for deliberately grown layers. Growth depends on temperature, oxygen availability, time, humidity, and the presence of other species. The structure can be amorphous or crystalline and may be uniform or graded.

Properties and function: Oxide films often act as barriers to diffusion, reducing ongoing oxidation and corrosion. They can impart electronic or optical properties and, in some metals, form a protective passive film that limits further attack. They may be color-tinted through interference effects (such as anodized aluminum) or serve as dielectric layers in electronics. Mechanical integrity and strong adhesion influence protective performance; breakdown or porosity can lead to local corrosion or wear.

Examples: Aluminum forms Al2O3; stainless steels develop a chromium-rich Cr2O3 passive film; titanium forms TiO2; silicon forms SiO2 used as a dielectric in microelectronics.

Measurement and applications: Oxide films are characterized by XPS, ellipsometry, TEM, and other surface techniques. Applications include corrosion protection, microelectronics, optics, and protective coatings.