Disclosed are methods of anodizing a metal component. In the methods an anodization bath includes an organic acid.

The present invention relates to a process for the at least two-stage coating of an electrically conductive substrate, the at least two-stage coating being carried out in a single dip-coating bath, the dip-coating bath comprising a coating material composition which comprises at least one cathodically depositable film-forming polymer and also an anodically depositable component, the anodically depositable component comprising anions of at least one phosphorus oxoacid; in a first stage, the electrically conductive substrate for coating is connected as anode in said dip-coating bath, and in a subsequent stage the now precoated substrate is connected as cathode in said dip-coating bath. The invention further relates to a substrate coated by the process of the invention.

A heat releasing pipe includes a metal pipe and a surface coating layer. The metal pipe has an outer circumferential surface. The surface coating layer is provided on the outer circumferential surface of the metal pipe. The surface coating layer contains an inorganic glass base material and has concave portions and convex portions on an outer surface of the surface coating layer. The concave portions and the convex portions are constructed using electrocoating with an electrocoating resin. The concave portions have a virtually circular shape when seen in a direction perpendicular to the outer circumferential surface of the metal pipe and are lower than a first reference surface. The first reference surface has an average height of the outer surface of the surface coating layer. The convex portions are located on peripheral edge portions of the concave portions and surround the concave portions.