Functionalized polysiloxane coatings on hot-rolled and high-strength Fe 430 B steel: Analysis of mechanical response and resistance to chemicals

Hybrid organic-inorganic coatings can be extremely beneficial to improve the performance of steel substrates as their outstanding adhesion strength, scratch resistance, and chemical endurance. However, the design and manufacture of the appropriate coating systems on the different metal alloys can be troublesome. Defective coatings can cause the deterioration of their performance, especially the resistance to aggressive chemicals. In this work, the deposition of functionalized methyl phenyl polysiloxane resins on hot rolled and high strength Fe 430 B steel substrates with and without an intermediate layer of a hybrid organic-inorganic grafting polymer (vinyltriethoxysilane) is comparatively evaluated. Visual appearance, scratch and wear resistance of the coatings as well as their attitude to act as chemical proof barriers are investigated. Proper functionalization of methyl phenyl polysiloxane resins with hydroxyl and alkoxy groups can lead to coatings that are well adhered to the underlying substrates, thus exploiting all the performance they were designed for. In this case, the use of an organo-silane interlayer can further increment the final properties of the overall coating systems.