Nanocomposites Allow Rust Proofing Without Chromium

Paint and Coatings Industry: "Researchers at the Fraunhofer Institutes for Silicate Research ISC in Wurzburg and for Machine Tools and Forming Technology IWU in Chemnitz,Germany, along with colleagues at the Institute for Corrosion Protection Dresden GmbH, have developed an alternative that is based on nanocomposites. 

'The new nanomaterials we developed using the sol-gel method adhere very well to most types of galvanization that we examined,' reports ISC project manager Dr. Johanna Kron. To produce them, the researchers dipped galvanized steel sheets into a coating sol and applied a powder coating. They subjected the coated sheets to a variety of load tests. One such test was to keep scratched steel sheets in a chamber filled with atomized brine for 360 hours, or 15 days, at a temperature of 35 degrees. 

They also placed the metal sheets in an environment chamber with a relative humidity of 100 percent for 240 hours, or 10 days. 'These coatings protect most galvanized materials almost as well as commercial yellow chrome plating. Indeed, the new coatings are often even more effective than the chromium-free system and chromium(III) passivation currently on the market,' says Kron."