| 摘要 |
A metallic surface is coated by reaction with one or more metallic oxides and/or hydroxides and is then phosphated by a buring-in process. The oxide or hydroxide is applied in solution or in suspension and burnt-in by heating at 800-1300 DEG C., if desired in an atmosphere of nitrogen or in vacuo. Oxides and hydroxides of the following metals may be applied:- Mg, Ca, Cr, Fe, and Al and Mn; alternatively a metallic compound which forms an oxide or hydroxide when burnt-in, e.g. carbonate, sulphate, acetate, oxalate or nitrate, may be used. Materials which may be employed in conjunction with the oxide or hydroxide are silicon, carbon in organically combined form e.g. cane sugar, SiO2, graphite, polyethylene powder and polyacrylic acid. Phosphating is effected by applying a solution containing e.g. ammonium phosphate alkaline earth (especially calcium) phosphate, magnesium phosphate, aluminium phosphate, urea phosphate or phosphoric acid, and burning-in at 200 DEG -800 DEG C. Other ingredients which may be included in the phosphate solution are wetting agents and inert fillers such as silicates, mica, Cr2O3, TiO2 and ZrO2. Surfaces of Fe, Fe alloys and steel may be coated. |
