Deposition of Hexagonal Boron Nitride from N‐Trimethylborazine (TMB) for Continuous CVD Coating of SiBNC Fibers

Abstract

Bonding strength between fibers and matrices of ceramic matrix composites (CMCs) is of great importance for the fracture behavior and can be adjusted by appropriate fiber coatings. In this study, the continuous coating of SiBNC fibers with hexagonal boron nitride (h‐BN) by CVD from TMB in an atmospheric pressure reactor is presented. Prior to fiber coating, the effects of deposition parameters, e.g., deposition temperature, concentration of the precursor and ammonia addition, and gas‐flow rate are investigated on flat Si substrates, and the results are utilized for the fiber coating. Ammonia concentration has no influence on the deposition rate. A maximum deposition rate of 0.044 kg m−2 h−1 for static conditions and 0.040 kg m−2 h−1 for continuous conditions can be achieved, which is comparable to the literature. The depositions are characterized for their composition and structure. Smooth homogeneous coatings with a thickness of 180–250 nm are found on the fibers. High‐resolution transmission electron microscopy (HRTEM) of the coated SiBNC fibers reveals that the hexagonal BN with 5 nm basal planes is mainly randomly oriented.

A Review on the Preparation of Borazine-Derived Boron Nitride Nanoparticles and Nanopolyhedrons by Spray-Pyrolysis and Annealing Process

“…BZ offers the advantage of being a colorless liquid with an adequate vapor pressure. As a consequence, it can be used in a second strategy in various vapor-phase processes [48,[59][60][61][62][63][64][65]. In the present section, the preparation of BZ-derived BN NPs by spray-pyrolysis is reported from the synthesis and characterization of BZ to the characterization and high-temperature thermal behavior of BN NPs.…”

Effect of coating on the color and surface hardness of the surface of dental ceramics

“…In another study, to increase the bond strength between fibers and ceramic matrix composites, coating of fibers with h-BN by chemical vapor deposition is presented. [ 30 ] One recent study found that CNT-reinforced Cr oxide coatings (reinforced with 8% CNT by weight and 92% Cr oxide by weight) increased microhardness by 30% and reduced porosity by 20%. [ 31 ] In a recent study, the physical properties of nickel-chrome (Ni–Cr) spinel infrared radiation coating, plasma spraying on metal substrate were investigated.…”

Chemical vapour deposition of sp2-hybridised B-C-N materials from organoborons

“…Some of them are derivative of borazine: B-trichloroborazine (B-TCBA, B3Cl3H3N3), hexachloroborazine (HCBA, 3Cl6N3), N-trimethylborazine (N-TMBA, B3H3(NCH3)3), B-trimethylborazine (B-TMBA, (BCH3)H3N3), N-triethylborazine (N-TEBA, B3H3(NCH2CH3)3) and N-tripropylborazine (N-TPBA, B3H3(NC3H7)3) are simple examples from the literature. Amorphous sp 2 -BN films were deposited from B-TCBA even above 1100 °C 282,283 , t-BN from HCBA at 900 °C 284 and t-BN from N-TMBA between 980 and 1080 °C 285 . Interestingly, the pyrolysis of N-TEBA and N-TPBA yielded amorphous films whose EELS spectra were similar to B4C 286 .…”