Oxidréteget

Oxidréteget, commonly translated as an oxide layer, is a thin film of oxide that forms on a material's surface when it reacts with oxygen. It can arise spontaneously when metals are exposed to air or moisture, or be produced deliberately by processes such as anodization, thermal oxidation, or chemical deposition.

The composition and structure of an oxide layer depend on the base material and the environment. Layers can be amorphous or crystalline and typically range from a few nanometers to several micrometers in thickness. A protective oxide layer adheres to the substrate and slows further oxidation by acting as a diffusion barrier for metal ions and reactants.

Oxide layers serve several roles. They provide corrosion resistance, influence mechanical properties, and can affect optical or electronic behavior. Notable examples include aluminum oxide (Al2O3) on aluminum, chromium oxide (Cr2O3) on stainless steels, and titanium oxide (TiO2) on titanium. Silicon dioxide (SiO2) is a widely used oxide in electronics and optics.

Formation and growth are governed by oxidation kinetics. Native oxide forms at ambient conditions; deliberate oxide growth uses thermal oxidation or anodization. Growth often follows parabolic or logarithmic kinetics, depending on diffusion through the layer and the environment.

Characterization techniques include X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and ellipsometry, among others, to determine composition, structure, and thickness.