From precursors to novel polymeric and ceramic coatings with tailored properties. The first review on coatings based on silicon preceramic polymers.

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Polysilazanes are excellent coating materials, because of their self‐crosslinking in air at low temperatures, high chemical and thermal stability, elevated hardness, and excellent adhesion to many different substrates. Therefore, coatings of two chemically different polysilazanes (crosslinked Durazane 1800 (HTTS)/perhydropolysilazane (PHPS)) are deposited by either dip or spray coating and crosslinked at 200 or 300 °C in air to investigate the chemical composition, surface energy, and coating adhesion in dependency on the precursor type and crosslinking temperature. The silazane HTTS possesses a higher amount of nonpolar organic groups resulting in a lower surface free energy. The anti‐adherence properties are investigated by using a phenolic resin via pull‐off adhesion, which is slightly reduced from 13 MPa for uncoated aluminum to less than 10 MPa for HTTS coated substrates. The addition of different amounts of poly(tetrafluoroethylene) (PTFE) particles causes a remarkable reduction of the surface free energy leading to a strongly reduced pull‐off adhesion of less than 4 MPa of the phenolic resin from the HTTS/PTFE coated substrates. The anti‐adherent properties remain even after repeated pull‐off tests. Because of the excellent properties, the HTTS/PTFE coatings are a very suitable system for easy mold release of plastic parts from metal molds and to replace commercial nonstick PTFE coatings.

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Polyacrylics have been widely used in coatings. However, their application is limited by low corrosion resistance. One way to enhance their properties is the addition of fillers with adequate properties. In this study, composite materials of PMMA and hBN were developed and deposited on steel by dip-coating. The influence of the amount of hBN in the PMMA coating regarding corrosion resistance was investigated. The surface and cross-section of the coatings were characterized by SEM, the porosity was investigated by systematic manual point count and the adhesion was classified according to the tape test standard. The produced coatings were submersed in NaCl and HCl solutions to analyze corrosion resistance. The results showed that the PMMA/hBN composite coatings improved the corrosion resistance in comparison with pure PMMA. Additionally, the coatings are crack free and well bonded to the metallic substrate.

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