| 摘要 |
PURPOSE:To form a zinc calcium phosphate film having excellent crystallinity in short time by setting the total acidity of a phosphate treating liquid to a value in a specific range in the stage of forming the zinc calcium phosphate film on the surface of iron or steel. CONSTITUTION:A liquid which contains 20-100g/l phosphate ion and 20-120g/ lnitrate ion, contains calcium ion and zinc ion at 0.2-2.0 ratio by weight of the calcium ion with respect to the zinc ion and 0.1-1.0 ratio by weight of the zinc ion with respect to the phosphate ion, contains, if necessary, nitrite ion and chlorate ion and has 50-150 point total acidity thereof is used in the stage of forming a phosphate film of zinc calcium phosphate on the surface of an iron or steel wire rod. The film of the zinc calcium phosphate having excellent crystallinity is formed in short time by an inline system on the surface of the iron or steel wire rod. |
