摘要 |
A manganese modified low zinc phosphate conversion coating is applied to a metal substrate by forming a coating composition having zinc ions, phosphate ions, nickel ions, manganese ions, and, optionally, iron ions, with a free acid range of 0.7 to 1.5 for spray applications, and 3.5 to 5.5 for immersion applications. The nitrate concentration is very low, generally less than 2000 ppm. The coating is applied with generation of minimal sludge, at lower temperatures, generally 120-160° F.
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