| 摘要 |
<p>To prevent the deterioration in water-resistant secondary adherence that occurs during prolonged use of a fluoride-containing phosphate conversion coating liquid composition to form a conversion coating on metal surfaces that are at least partly aluminiferous, the aluminum compound-containing sludge produced in the phosphate conversion coating liquid composition as it is used is coagulated and sedimented by adding at least one cationic polymeric coagulant to the sludge-containing phosphate conversion coating liquid composition.</p> |
