ZINC PHOSPHITE COMPOSITION, RUST PREVENTIVE PIGMENT AND PRODUCTION THEREOF

PURPOSE:To improve the rust preventing performance by reacting an electroless plating aged solution with a Zn compound, using the resultant ZnHPO3 as a principal component and then including one or more of salts of specific acids with a metal selected from Zn, Ni and/or Co therein. CONSTITUTION:An electroless plating aged solution (containing 4-7g/l Ni ions, 30-55g/l hydroxycarboxylate ions, 25-55g/l hypophosphite ions, 80-100g/l phosphite ions, 30-45g/l sulfate ions, etc.) is added to a Zn compound slurry of ZnO2, etc., dispersed in water and a pH adjustor such as Na2B4O7 is added to the obtained mixture solution at 40-80 deg.C while stirring the mixture solution. Na2 MoO4.2H2O and H2O2 are subsequently added to carry out the oxidizing treatment and the resultant solution is then aged. The formed precipitate is subsequently filtered and washed with water and then dried to afford the objective ZnHPO3 composition, consisting essentially of ZnHPO3 having 0.5-15mum average particle diameter and containing a hypophosphite, a phosphite, a phosphate, a borate, a silicate, a molybdate and a hydroxycarboxylate of a metal selected from Zn, Ni and/or Co.