NANOMETRIC BORON-NITRIDE POWDERS - LASER SYNTHESIS, CHARACTERIZATION AND FT-IR SURFACE STUDY

Boron nitride powders in the nanometric range were synthesized by lase r driven reactions in BCl3-NH3 mixtures. The gaseous reactants were se parately introduced in the beam of a high-powered continuous wave CO2 laser. The powders with high specific surface area (up to 230 m2 g-1) present the turbostratic structure as characterized by TEM. The evolut ion towards the hexagonal structure by heating the powders up to 1920 K under nitrogen flow was followed by XRD. One BN powder has been full y characterized by infrared and Raman spectroscopies regarding bulk st ructure and identification of surface species as well.