Abstract: A coating composition for use in protecting metallic substrates from corrosion, comprising in weight percent, based on the total weight of the composition; from about 10% to 20% of a film forming substance; from about 45% to 55% of zinc powder, from about 25% to 35% of zinc dust; from about 1.5% to 2.5% of hollow glass microspheres having diameters ranging from 1 to about 150 microns and a true density of 0.3 to 1.1; from about 2% to 15% by weight of the film forming substance, of a hardener, about 1% to 2% by weight of the film forming substance, of an amorphous silica; and about 0.3% to 1% of a flow control agent.