Development of cost-effective steel coatings promotes the optimization of the press hardening process. The latter utilizes austenite-martensite transition to achieve a high tensile strength of steels. Upon such transition a steel plate is quenched from ca. 950 °C down to 200 °C within a minute and simultaneously stamped by a press. However, intense rust formation hinders further processing of stamped details unless protective measures are applied. In this contribution a strategy for the application of a protective coating using water-based nanoparticle dispersions is presented. While multimodal particle size distribution aimed for low shrinkage of the green biscuit, chemical composition of the applied dispersions was fine-tuned for an optimal temperature cycle for the press hardening process. In contrast to previously reported coatings based on the classical sol-gel process, the protective ability of the particulate silicate coatings reaches up to 950 °C as demonstrated by thermogravimetric analysis. The reported coating system can be compared to the standard Usibor® coating, which is widely used nowadays in industry. To illustrate the issue, results on corrosion potential and corrosion current, as well as on the impedance response are reported here. Although Usibor®-coatings demonstrate better passivation in aqueous media, the temperature treatment cycle of the press hardening can be considerably accelerated in case of the silicate coatings.
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