Preparation of BN coating on quartz fibers by a low-temperature reaction

Turbostratic boron nitride (BN) coatings (amorphous with some microcrystallinity) were successfully deposited on quartz fibers and quartz fabrics by dip-coating using boric acid and urea nitriding in a nitrogen gas. The samples were characterized by means of XRD, SEM, IR, Raman, TEM, etc, indicating that the coating layer was composed mainly of amorphous and nano-sized BN particles with a pebble-like structure nitriding in a nitrogen gas flow at 850°C for 5 h. The quality of the coating changed with the dipping times. The surface of the fibers existed a quantity of holes by one dipping, and the holes disappeared with the increasing dipping times. The surface of the fibers was smooth and glassy, and stripping or cracking at the surface have not been observed after third dipping. Many agglomerates have been observed as dipping more than three times.