Abstract: A coating composition for a metal substrate having excellent adhesion, corrosion resistance and welding property which comprises (A) an epoxy resin, (B) an organic phosphorus compound, (C) zinc powder, of which a portion being replaceable by (E) a solid electroconductive material, and (D) a magnesium compound dispersed in a liquid medium, the weight proportion of the components (A) and (B) being from 45:55 to 95:5, the content of the component (C) corresponding to from 30 to 95% by weight based on the total weight of the non-volatile components in the composition and the content of the component (D) being from 0.1 to 5% by weight based on the total weight of the non-volatile components in the composition.

Abstract: A process for preparing metal salts of alkyl phosphate of either one of the formulae: ##STR1## WHICH COMPRISES REACTING AN ALKYL PHOSPHATE OF EITHER ONE OF THE FORMULAE: ##STR2## in the form of its alkali metal salt with a metal salt of the formula: M.sub.n X.sub.m in an aqueous medium at a temperature of from about 50.degree. to 80.degree. C. (wherein R is an alkyl group of not less than 12 carbon atoms, M is an alkaline earth metal, aluminum or zinc, X is halogen ion, sulfate ion or nitrate ion, l is an integer corresonding to the atomic valency of M, r is an integer of 0, 1 or 2, m is an integer of 1, 2 or 3 and n is an integer of 1 or 2).