Corrosion inhibitors in breakable microcapsules to passivate scratched metals

Abstract

Microencapsulated chemical(s), as water-soluble solid particles, are embedded in at least one the paint layers on the surface of a magnesium article used in an automobile. If the protective paint film is scratched or otherwise mechanically disturbed to expose the surface of the magnesium article the capsules will be ruptured. This will expose the encapsulated chemical(s) to ambient water enabling them to dissolve and form an aqueous solution capable of reacting with the exposed magnesium to form a protective passivating layer on the exposed magnesium to resist corrosion. In a second embodiment the encapsulated chemicals include a deliquescing compound for extraction of moisture from the atmosphere sufficient to induce dissolution of the passivating layer-forming chemical(s) and trigger the formation of the passivating layer in the absence of ambient water.