Inorganic film forming composition for coating

Claim 1

An inorganic film forming composition particularly adapted for use as a coating over a zinc rich coating which consists essentially of: (A) colloidal silica dispersed in water in an amount of about 10-50% by weight as SiO 2 ; (b) at least one water soluble organic amine selected from the group consisting of monoethanolamine, diethanolamine, isopropanolamine, ethylenediamine, isopropylamine, diisopropylamine, morphorine, triethanolamine, diaminopropane and aminoethyl ethanolamine in a weight ratio of amine to silica of 1:100 to 2:1; (C) at least one powdery aluminum compound selected from the group consisting of aluminium oxide, aluminum hydroxide, aluminum silicate, potassium aluminium silicate, calcium aluminum silicate, calcined products of other metallic oxides and inorganic pigments treated by aluminum compounds on the the surface thereof, in a weight ratio of SiO 2 to powdery aluminum compound of 1:50 to 5:1; (D) powdery glass having an average particle size of 1 to 100 microns; (E) up to 15 weight percent based on the weight of the water of at least one water soluble amino acid selected from the group consisting of glycine, alanine, aminobutyric acid, valine, norleucine, norvaline and serine; (F) up to 10% by weight based on the weight of water of thiourea; (G) up to 55% by weight based on the weight of water of urea; and (H) up to a molar ratio to silica of 1:50 of at least one water soluble salt of a transition metal or potassium, sodium or ammonium salt of said transition metal wherein said transition metal selected from the group consisting of chromium, molybdenum, tungsten, iron, cobalt, manganese and vanadium.