IMPROVEMENT OF BORON-RICH BORONITRIDE ADHESION THROUGH TITANIUM BORONITRIDE ON GLASS SURFACES AND OPTICAL FIBERS BY DIAMMONIUM HEXAFLUOROTITANATE(IV) AND BORAZINE

Titanium boronitride (Ti-B-N) films have been produced by solid-gas re action in the temperature range 600-700 degrees C using [(NH4)(2)TiF6] and B3N3H6 (borazine) as precursors. The resulting material is deposi ted on SiO2 substrates and on optical fibers, respectively. Films with thicknesses ranging from 0.3 to 1 mu m possess a characteristic black color. They are stable over a wide temperature range, exhibit strong adhesion to glass and quartz glass and show resistance to mechanical d eformation (i.e., fracture toughness). Furthermore, the ceramic films are not oxidized at room temperature even by strong oxidizing acids su ch as concentrated HNO3. Auger electron spectroscopy (AES) depth profi le analyses indicate that the Ti concentration decreases progressively from the interface to the surface of the film. Results obtained by Ru therford backscattering spectroscopy (RES) studies agree well with tho se of AES. Moreover, the decomposition products of [(NH4)(2)TiF6] are involved in the reactions at the surface of the substrate, enhancing t he adhesion of the film. AFM analyses show a columnar type film growth with grain sizes ranging from 200 to 700 nm. The films possess electr ical resistivity and hardness on the order of 6000 mu Omega cm and 22 Gpa (Vickers), respectively.