CHARACTERIZATION OF THE NITRIDATION PROCESS OF BORIC-ACID

Boric acid B(OH)(3) has been thermally nitrided under flowing ammonia into a boron oxynitride. This reaction has been followed using various structural techniques: X-ray photoelectron spectroscopy (XPS), infrar ed spectroscopy (IR), X-ray diffraction and chemical analyses. Reactio n of boric acid with ammonia began at 155 degrees C. The weight percen t of nitrogen increases with the temperature of the pyrolysis process. Formation of B-N bonds is observed at 400 degrees C by infrared spect roscopy. Two boron species are observed by XPS and identified as boron linked mostly to oxygen atoms and as boron linked mostly to nitrogen atoms, denoted BOx and BNx, respectively. The intensity of the BNx sig nal increases with the pyrolysis temperature.