Carbothermic formation of boron nitride

Aydogdu, A
Sevinc, N
Formation of boron nitride by reaction of boric oxide with carbon and nitrogen was studied. It was found from the results of experiments conducted by holding BA-activated C mixtures under a flowing nitrogen atmosphere that formation of boron nitride was complete in 120 min at 1500 degreesC. After cleaning the reaction product from the ash of the activated carbon and from the unreacted B2O3 pure BN powder was obtained. B4C was found to exist as an intermediate species in the reaction products of the experiments in which BN formation was not complete. The results of experiments conducted with the objective of gaining an insight into the reaction mechanism by using different geometrical arrangements show that liquid 13,03 and solid carbon need not be in contact in the formation of BN from B2O3, C and N-2 and indicate that the reaction proceeds through a gaseous boron containing species which is most probably B2O3(g)


Effect of calcium carbonate addition on carbothermic formation of hexagonal boron nitride
ÇAMURLU, HASAN ERDEM; SEVİNÇ, NACİ; Topkaya, Yavuz Ali (Elsevier BV, 2008-01-01)
Effect of CaCO3 on formation of hexagonal boron nitride (h-BN) was investigated by holding CaCO3 free and CaCO3 added activated carbon-boric oxide mixtures under nitrogen atmosphere at 1500 degrees C for 30-120 min. Amount of CaCO3 addition was varied in the range of 0-50 wt.% of the initial mixture. Products were characterized by powder X-ray diffractometry, FT-IR analysis, quantitative chemical analysis, scanning electron microscopy and BET specific surface area analysis. It was observed that calcium carb...
TIMUCIN, M; MUAN, A (Wiley, 1992-06-01)
Activities of NiO were measured in the oxide and spinel solutions of the system MnO-NiO-Al2O3 at 1300-degrees and 1400-degrees-C with the aim of deriving information on the thermodynamic properties of the spinel phases. Synthetic samples in selected phase assemblages of the system were equilibrated with metallic nickel and a gas phase of known oxygen partial pressures at a total pressure of 1 atm. The data on NiO activities and directions of conjugation lines between coexisting oxide and spinel phases were ...
Kinetic model for alpha-tricalcium phosphate hydrolysis
Durucan, Caner (Wiley, 2002-08-01)
A mechanistic model for the kinetics of hydrolysis of alpha-tricalcium phosphate (alpha-Ca-3(PO4)(2) or alpha-TCP) to hydroxyapatite (Ca10-x(HPO4)(x)(PO4)(6-x)(OH)(2-x) or HAp) has been developed. The model is based on experimental hydrolysis rate data obtained using isothermal calorimetry. Analysis of the kinetic data according to the general kinetics models in terms of the fractional degree of reaction and time suggests the hydrolysis to be controlled by different rate-limiting mechanisms as reaction proc...
Combustion synthesis of calcium phosphate bioceramic powders
Tas, AC (Elsevier BV, 2000-12-01)
Calcium phosphate (hydroxyapatite and tri-calcium phosphate) bioceramics closely resembling, in chemical composition, those found in vivo in human bones have been synthesized by using novel synthetic body fluid solutions via the self-propagating combustion synthesis (SPCS) method. Powder characterization was performed by XRD: ICP-AES, FTIR and SEM.
Solid-state synthesis and X-ray diffraction studies of Na2S
Kizilyalli, M.; Bilgin, M.; Kizilyalli, H.M. (Elsevier BV, 1990-4)
Na2S was synthesized by a new solid-gas reaction of Na2CO3 with a sulfidizing gas mixture and a solid-solid reaction of carbon with Na2SO4. The reaction products were analyzed by X-ray powder diffraction and IR methods. Two new crystal modifications of Na2S were identified in addition to the previously reported antifluorite structure. They were designated as cubic Form II and orthorhombic Form III. The approximate unit cell dimensions were found to be a = 11.29 Å for the cubic form and a = 15.94, b = 16.00,...
Citation Formats
A. Aydogdu and N. Sevinc, “Carbothermic formation of boron nitride,” JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, pp. 3153–3161, 2003, Accessed: 00, 2020. [Online]. Available: