Abstract-Currently, a very popular method to reduce the corrosion on zinc is to use chemical conversion coating layers based on Cr +6 . However, certain issues must be overcome to use chromium salts due to restrictions resulting from legislation targeting environmental protection. This study investigates the optimum conditions to form high-strength steel sheets (SPFC780) using an organic/inorganic solution containing Si. The curing duration for the coating solution was of 1, 2 and 3 minutes at a temperature of 463 K. Seven types of coating solution were used, and the corrosion resistance improved as the heat treatment time increased. The optimal coating solution was the urethane of 21 wt.%, the SiO 2 polysilicate of 7 wt.% and the melamine of 3 wt.%.