Coating systems for metal substrates and a method for protective metal substrates using the coating systems

A method of treating a metal to improve the metal's corrosion resistance, said method comprising:

• applying, to the surface of the metal, a coating which consists essentially of magnesium powder and an inorganic binder,
• wherein the inorganic binder comprises a tetraalkyl orthosilicate;
• or
• wherein the inorganic binder comprises one or more trialkoxy monoalkyl silanes and one or more tetraalkyl orthosilicates;
• or
• wherein the inorganic binder comprises two or more trialkoxy monoalkyl silanes and one or more tetraalkyl orthosilicates and wherein at least one of the trialkoxy monoalkyl silanes is an amine-containing trialkoxy monoalkyl silane;
• or
• wherein the inorganic binder comprises two or more trialkoxy monoalkyl silanes and one or more tetraalkyl orthosilicates and wherein at least one of the trialkoxy monoalkyl silanes is an acrylate-containing or methacrylate-containing trialkoxy monoalkyl silane;
• or
• wherein the inorganic binder comprises two or more trialkoxy monoalkyl silanes and one or more tetraalkyl orthosilicates and wherein at least one of the trialkoxy monoalkyl silanes is an amine-containing trialkoxy monoalkyl silane and wherein another of the trialkoxy monoalkyl silanes is an acrylate-containing or methacrylate-containing trialkoxy monoalkyl silane.