Effect of sodium carbonate on carbothermic formation of hexagonal boron nitride

Akyıldız, Uğur
Effect of Na2CO3 on formation of hexagonal boron nitride (h-BN) by carbothermic method has been studied by subjecting B2O3-C and Na2CO3-added B2O3-C mixtures to N2 (g) atmosphere. Na2CO3 amount in the mixtures was changed in the range of 0-40 wt. %. Time and temperature were used as experimental variables. Reaction products were analyzed by XRD and scanning electron microscope. Na2CO3 was found to increase both the amount and the particle size of h-BN similar to CaCO3 [1]. Na2CO3 was found to be less effective than CaCO3 in increasing the amount while it was more effective than CaCO3 in increasing the particle size of h-BN forming.


KOCAK, HI; ARAS, L (Elsevier BV, 1990-07-01)
The solution behaviour of Na, Ba, Zn and Al ionomers of methyl methacrylate-methacrylic acid copolymer (P(MMA-MAA)) with different ion contents has been studied by viscosity and dipole moment measurements. Two solvents with different character are chosen for viscosity measurements: dioxane (ε = 2.22) and acetone (ε = 20.7). The expected polyelectrolyte behaviour of the ionomers in acetone is reflected by the viscometric measurements. Mean squared dipole moment 〈μ2〉 values are calculated over a temperature r...
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...
Effect of the number of cycles on the optical and structural properties of Mn3O4 nanostructures obtained by SILAR technique
BAYRAM, ÖZKAN; Simsek, Onder; GÜNEY, HARUN; İĞMAN, ERDAL; Ozer, Mustafa Murat (Springer Science and Business Media LLC, 2018-06-01)
In this study, nanostructured Mn3O4 (manganese oxide) thin films were successfully obtained by successive ionic layer adsorption and reaction (SILAR) method on the soda lime glass substrates using Manganese Nitrate (Mn(NO3)(2)) and Ammonium hydroxide (NH4(OH)) as cationic and anionic precursors respectively. Structural and morphological characterizations of the Mn3O4 films obtained at different cycles were determined using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The crystal structure...
Effect of impact modifier on the properties of poly (ethylene terephthalate)-organoclay nanocomposites
Yılmazer, Ülkü; Alyamac, Elif (2006-11-30)
The effects of component concentrations and addition order of the components, on the final properties of ternary nanocomposites composed of amorphous poly (ethylene terephthalate) matrix, organically modified clay, and an ethylene / methyl acrylate / glycidyl methacrylate (E-MAGMA) terpolymer were studied. All formulations were prepared by melt compounding of the components with a two-step mixing procedure in a corotating twin-screw extruder. Considering the X-Ray Diffraction, SEM, impact and strain at brea...
Effect of pH in an aqueous medium on the surface area, pore size distribution, density, and porosity of montmorillonite
Altin, O; Özbelge, Hilmi Önder; Dogu, T (Elsevier BV, 1999-09-01)
Surface area, pore volume distribution, and porosity of montmorillonite are determined after being exposed to aqueous solutions with various pH values. For measurement, after each pH treatment the clay samples were freeze-dried in order to keep the structure of the clay same as that in the aqueous solution. Surface area and pore size distribution measurements were performed on an unmodified and four pH (2.5, 4.0, 5.5, 9.0)-adjusted clay samples using N-2 and CO2 as adsorbates. The surface area measurements ...
Citation Formats
U. Akyıldız, “Effect of sodium carbonate on carbothermic formation of hexagonal boron nitride,” M.S. - Master of Science, Middle East Technical University, 2010.