Sealer

We call it materials that are used to improve the properties of phosphate coatings and increase their durability. Sealer is used after phosphate coatings, which improves the corrosion resistance of phosphate coatings and increases paint adhesion.We divide them into two types: chrome-containing and chrome-free.

Chrome sealer

These sealers contain hexavalent chromium compounds, which are highly toxic. These compounds react with the metal to form a thin, corrosion-resistant layer. Their advantages are that they provide a highly corrosion-resistant coating and have better adhesion to the metal surface than non-chrome sealers. Their disadvantages are that they are toxic and hazardous to the environment and human health.

Chrome-free sealer

These sealers use alternative chromium-free compounds such as phosphates, silicates, or organic compounds. These materials react with the metal and form a protective layer, but with less toxicity. Their advantages are that they are environmentally friendly and non-toxic. Their disadvantages are that they may not be as corrosion resistant as chromium-based sealers and they provide less adhesion in some cases.

Overall, despite the higher strength benefits of chrome-containing sealers, the use of chrome-free sealers is preferred due to environmental risks.