Synthesis And Characterization Of B-C-N Ternary Compounds

One of the key areas that have attracted a lot of attention in current lightelement materials research field is the experimental synthesis of novelmaterial BCN. On the basis of summarizing the theoretical and experimentaldevelopment of BCN ternary compound, we study the experimentalsynthesizing of B-C-N ternary compounds by the catalytic pyrolysis oforganic precursors and mechanical alloying method. Using Fe and MgO ascatalyst, Trimethylamine borane(DMAB) as raw material, we synthesizeB-C-N compounds through catalytic dehydrogenation. Using graphite andh-BN as raw material, selecting different ball-to-powder ratio, we synthesizeB-C-N compounds through mechanical alloying method. The morphology,phase forms, chemical compositions and bond structures of synthesizedproducts are characterized by scanning electron microscope (SEM),transmission electron microscope (TEM), X-ray diffraction (XRD), fouriertransform infrared spectroscopy (FTIR), laser Raman spectroscopy (Raman),X-ray photoelectron spectroscopy (XPS), Uv-vis absorption spectrum (Uv-vis) and BET.The B-C-N compounds with random layer graphite structure aresynthesized by mechanical alloying method of graphite powder and h-BNpowder with different ball-to-powder ratio. The products are a series ofB-C-N compounds from amorphous to turbostratic structure. When themilling time lasted240h, products appear amounts of hexagonal B-C-Ncrystalling phase. Further Fourier transformed infrared measurementindicates that B-C, C-N, B-N and B-C-N bonds exist in the products. Inadditional, the products contains C=N bond when the ratio of ball-to-powderis20:1. UV-visible spectra showed that there is a strong absorption peak ofthe products in the UV range. The results of specific surface area show thatthe specific surface area of a single port of the products is3.6035m2/g, porevolume for0.019187cm3/g, Pore Size for200.5122nm.The B-C-N compounds by mechanical alloying method possess goodthermostability and strong inoxidizability whether in the nitrogen or atmospheric environment.At pyrolysis temperature of the500℃for0.5h, the B-C-N compoundsare synthesized by the catalytic pyrolysis of organic on the action of Fe andMgO catalysis in the vacuum condition. BCN’s diffraction peaks are notfound in the X-ray diffraction analysis of the synthetic products. X-raydiffraction analysis of trimethylamine borane showed that the diffractionpeaks at19.14°,26.82°,33.46°,43.28°. Further Fourier transformed infraredmeasurement indicates that B-N, C-N, N-H, C-H and B-H bonds exist intrimethylamine borane. The FT-IR of the pre-dehydrogenation product showsthat after pre-dehydrogenation treatment, the B-H, C-H and N-H bonds intrimethylamine borane weakened or disappear, that may be an obviouschemical reaction, the old bonds rupture and then new bonds formation.At pyrolysis temperature of the500℃for0.5h，the B-C-N compoundsare synthesized by the catalytic pyrolysis of organic on the action of MgOcatalysis in the vacuum condition. X-ray diffraction analysis shows that MgOand an unknown phase to the product under the conditions. The diffraction peaks of BCN are not found. This indicates that MgO plays a catalytic role inthe experiments.