| abstract |
PROBLEM TO BE SOLVED: To reliably impart a high rust preventive effect to a metal substrate for a long period of time even when a rust preventive film is formed with a chromium-free rust preventive agent. A rust-preventing coating composed of an inorganic composition containing a metal powder and substantially not containing chromium is formed on a rust-preventing base layer on the surface of a metal substrate treated with a rust-preventing base agent. Prepare a rust-proof coating. The rust preventive underlayer may be a metal phosphate coating such as an iron phosphate coating. The corrosion potential of the rust preventive coating may be, for example, -1100 to -800 mV (particularly about -1100 to -900 mV). The inorganic composition may contain at least a plate-like zinc powder (for example, a plate-like zinc powder and a binder component, in particular, a plate-like zinc powder, a plate-like aluminum powder and a silicon-containing binder). The rust preventive film may be composed of a plurality of layers. The antirust coating may have a structure in which plate-like metal powders are laminated. [Selection figure] None |