What should be done when flash rust occurs during the phosphating process?

Phosphating is a commonly used pretreatment technology, fundamentally classified as a chemical conversion coating process. It is primarily applied to steel surfaces but can also be used on non-ferrous metals such as aluminum and zinc. Its main purposes include: providing protection to the base metal to prevent corrosion to a certain extent; serving as a primer before painting to enhance paint adhesion and corrosion resistance; and acting as a friction-reducing lubricant in metal cold working processes.

Low-temperature phosphating is a process where phosphate conversion coatings are formed through chemical and electrochemical reactions. The resulting phosphate conversion layer is termed a phosphating film. While convenient and energy-efficient, it exhibits poor salt spray resistance and limited inherent rust prevention—typically lasting only about a week. Additionally, flash rusting often occurs during drying, compromising subsequent coating applications.

The solution is relatively straightforward: adding a small amount of flash rust inhibitor to the phosphating solution addresses flash rust during drying. This inhibits oxidation reactions on the phosphating film surface, effectively preventing the spread of minor rust spots and reducing flash rust risk. The inhibitor forms stable chemical reaction products with the metal surface, further enhancing the phosphating film's rust prevention capability. In phosphating processes, selecting a highly effective, practical product that offers corrosion resistance, salt spray resistance, and superior flash rust prevention is crucial.

We have specifically developed a flash rust inhibitor tailored for phosphating applications. It excels in performance, quality, cost-effectiveness, environmental compatibility, and safety, making it suitable for various systems and different metal substrates. Additionally, our dedicated R&D team can provide customized solutions tailored to your specific requirements.