Rustvorm

Rustvorm, literally “rust form” in Dutch, is a term used in materials science and conservation to categorize the morphology of rust on iron and steel. It describes the distinctive patterns and structures that rust can assume as corrosion progresses under varying environmental conditions. The concept helps distinguish the history of exposure, such as humidity cycles, salt presence, and temperature fluctuations, from simple surface oxidation.

Dendritic rust forms are tree-like arrays of iron oxides that grow in rapid diffusion processes and are often observed in high humidity. Lamellar rust produces layered, sheet-like deposits indicating cyclic wetting and drying. Ring or concentric rust can develop around localized pits due to diffusion-limited corrosion. Nodular rust forms are spherical or globular patches often seen on rough or pitted surfaces.

Key factors shaping rustvorm include alloy composition, protective coatings, water activity, oxygen availability, chloride content, temperature, and microstructural features such as grain boundaries. The interaction of these factors yields specific forms and growth rates that can be diagnostic of the exposure history.

Applications include conservation of artifacts, forensic metallurgy, and predictive modeling of corrosion. Rustvorm analysis can help assess deterioration risk, inform stabilization strategies, and support restoration planning.

See also: rust; corrosion; patina; oxide layer; materials science; conservation.