| 摘要 |
An aqueous liquid combination of simple and complex fluorides, citric acid and/or its salts, phosphate ions, a hydroxylamine source, and an oxidizing agent selected from among water soluble nitroaromatic organic compounds, molybdates, and tungstates, provides good quality protective phosphate conversion coatings on ferrous, zinciferous, aluminous, and magnesium and magnesium alloy metal surfaces, without needing any divalent or higher valent metal cations such as are generally used to produce high quality phosphate conversion coatings. These combinations that contain citric acid produce less sludge than otherwise similar combinations in which gluconic acid is used instead of citric acid. If the combination includes suitable surfactants, no prior chemical cleaning of the metal to be treated is required for good results. |
