Synthesis of nanostructural turbostratic and hexagonal boron nitride coatings on carbon fiber cloths by dip-coating

Abstract The fabricating and characterization of boron nitride coating onto carbon fiber cloths via dip-coating process with boric acid and urea as precursors, followed by nitriding in a nitrogen flow were done in this study. Temperature and dip-coating cycles were considered as variables to find out optimum amounts. Dip-coating process has done in 1, 2 and 4 cycles. Also, nitridation process was done in different temperatures of 650 and 1000 °C. The results show that boron nitride coatings exhibited a pebble-like structure. The SEM micrographs indicated that the thickness of nanostructural coatings among 1, 2 and 4 cycles of dip-coating is about 55, 120 and 210 nm, respectively. By increasing dip-coating cycles, smoother surface was developed. The FT-IR and XRD results revealed that the boron nitride film fabricated at 650 °C has turbostratic microstructure and by increasing the nitridating temperature to 1000 °C, hexagonal boron nitride phase was indicated through the film. Thermal analysis revealed that boron nitride crystallization starts at temperature of 600 °C.