Journal of the American Ceramic Society-Leparoux et al. Vol. 82. No. 5 (b) Fig. 10. TEM lattice fringes of the BN coating obtained by classical ICVI ( 28 x 10-6 kg/s)((a)inside the Bn deposit and (b)near the fiber/BN interface); the electron-diffraction result also is shown. (a) (b) (d) Fig. 11. TEM lattice fringes of the BN coating obtained via protected-ICVI ( 28 x 10 kg/s)((a) the external portion of the deposit,(b) tween the external portion and the middle, (c)the middle of the coating, and(d) near the fiber/BN interface), the electron-diffraction result also tions, followed by thermal treatment steps did not permit either the reactant(PBCl, or PNH,, whichever has the process to improve the Bn organization all cases, the deposition conditions at the ga depart very much from the approximate eq between IV. Discussion he gas phase and the solid; i.e., the supersaturation is high. If we suppose that no intermediate precursors are produced via At 700oC, the CVd process is limited either by a homogeneous reactions, a local equilibrium at the interface transfer with the chemical kinetics at low fl would be represented by reaction(1) rates ne chemical kinetics alone at high flow rates where rate is only governed by the partial pressure of BCl3+ NH3 F<BN>+3HCItions, followed by thermal treatment steps did not permit either process to improve the BN organization. IV. Discussion At 700°C, the CVD process is limited either by a combina￾tion of mass transfer with the chemical kinetics at low flow rates or by the chemical kinetics alone at high flow rates where the deposition rate is only governed by the partial pressure of the reactant (pBCl3 or pNH3 , whichever has the lowest value). In all cases, the deposition conditions at the gas/solid interface depart very much from the approximate equilibrium between the gas phase and the solid; i.e., the supersaturation is high. If we suppose that no intermediate precursors are produced via homogeneous reactions, a local equilibrium at the interface would be represented by reaction (1): BCl3 + NH3 →← ,BN. + 3HCl (1) Fig. 10. TEM lattice fringes of the BN coating obtained by classical ICVI (f 4 28 × 10−6 kg/s) ((a) inside the BN deposit and (b) near the fiber/BN interface); the electron-diffraction result also is shown. Fig. 11. TEM lattice fringes of the BN coating obtained via protected-ICVI (f 4 28 × 10−6 kg/s) ((a) the external portion of the deposit, (b) between the external portion and the middle, (c) the middle of the coating, and (d) near the fiber/BN interface); the electron-diffraction result also is shown. 1192 Journal of the American Ceramic Society—Leparoux et al. Vol. 82, No. 5