Chromate Conversion Coatings

Zinc is typically used for the electrodeposited coating for iron and steel when prevention of atmospheric corrosion is the primary objective.   However without a subsequent treatment, typically chromate, electrodeposited zinc becomes dull and grey and will quickly develop white corrosion products after exposure to air.  Chromate conversion coatings impart both an aesthetically pleasing finish as well as varying degrees of corrosion protection. The use of Chrome VI in the conversion coatings as the passivation agent for zinc deposits are endowed with numerous advantages.  These include: High … [Read more...]

Functional Zinc Processes

Zinc is one of the most widely used functional sacrificial coatings to inhibit corrosion of ferrous metals. Over the years a variety of Zinc plating and post treatment chemistries (chromates –hexavalent and trivalent-- and seals) have been developed to improve the aesthetics and functionality of zinc coatings. Over the years there have been three types of zinc processes: Cyanide based chemistry – seldom used today because of safety issues, waste treatment and disposal cost—but still it is needed in some applications. These processes were very forgiving and easy to control. Environmental … [Read more...]