Mechanochemical and volume combustion synthesis of ZrB2

Akgun, Baris
Topkaya, Yavuz Ali
Formation of ZrB2 by volume combustion synthesis (VCS) and mechanochemical process (MCP) from ZrO2-Mg-B2O3 was studied. Production of ZrB2 by VCS in air occurred with the formation of side products, Zr2ON2 and Mg3B2O6 in addition to MgO and ZrB2. Zr2ON2 formation was prevented by conducting VCS experiments under argon. Wet ball milling was applied to the VCS products before leaching for easier removal of Mg3B2O6 phase. MgO and Mg3B2O6 were removed from wet ball-milled products by leaching in 5 M HCI for 2.5 h. In MCP, 30-hour ball milling was found to be sufficient for the formation of ZrB2 with no minor phase formation. Leaching of MCP products in 1 M HCI for 30 min was sufficient to remove MgO. Complete conversion of ZrO2 to ZrB2 did not take place in both production methods, even with excess amounts of Mg and B2O3. Therefore, formed ZrB2 contained residual ZrO2.


Molecular dynamics study of random and ordered metals and metal alloys
Kart, Hasan Hüseyin; Tomak, Mehmet; Department of Physics (2004)
The solid, liquid, and solidification properties of Pd, Ag pure metals and especially PdxAg1-x alloys are studied by using the molecular dynamics simulation. The effects of temperature and concentration on the physical properties of PdxÞAg1-x are analyzed. Sutton-Chen (SC) and Quantum Sutton-Chen (Q-SC) many-body potentials are used as interatomic interactions which enable one to investigate the thermodynamic, static, and dynamical properties of transition metals. The simulation results such as cohesive ene...
Effect of swaging on microstructure and tensile properties of W-Ni-Fe alloys
DURLU, NURİ; Caliskan, N. Kaan; Bor, Sakir (Elsevier BV, 2014-01-01)
The objective of this study was to investigate the effect of swaging on the microstructure and tensile properties of high density two phase alloys 90W-7Ni-3Fe and 93W-4.9Ni-2.1Fe. Samples were liquid phase sintered under hydrogen and argon at 1480 degrees C for 30 min and then 15% cold rotary swaged. Measurement of microstructural parameters in the sintered and swaged samples showed that swaging slightly increased tungsten grain size in the longitudinal direction and slightly decreased tungsten grain size i...
Effects of fabrication method on initial powder characteristics and liquid phase sintering behaviour of tungsten
Erol, Mahmut; Erdogan, Metehan; Karakaya, İshak (Elsevier BV, 2018-12-01)
Direct electrochemical production of tungsten involves removal of oxygen in solid state from an important tungsten compound, calcium tungstate, in molten salts. A detailed experimental study was performed to characterize the liquid phase sintering behaviour of the tungsten powder (WE), which was produced by the direct electrochemical reduction technique. All of the tungsten heavy alloy (WHA) compositions covered in this study, contained four parts nickel, one part cobalt and over 90 wt% tungsten. The pellet...
Surface energy and excess charge in (1x2)-reconstructed rutile TiO2(110) from DFT plus U calculations
Unal, Hatice; METE, ERSEN; Ellialtıoğlu, Süleyman Şinasi (2011-09-09)
Physically reasonable electronic structures of reconstructed rutile TiO2(110)-(1x2) surfaces were studied using density functional theory (DFT) supplemented with Hubbard U on-site Coulomb repulsion acting on the d electrons, the so called DFT + U approach. Two leading reconstruction models proposed by Onishi and Iwasawa [Surf. Sci. Lett. 313, 783 (1994)] and Park and coworkers [Phys. Rev. B 75, 245415 (2007)] were compared in terms of their thermodynamic stabilities.
Electrochemical polymerization of 9-fluorenecarboxylic acid and its electrochromic device application
Bezgin, Buket; CİHANER, ATİLLA; Önal, Ahmet Muhtar (Elsevier BV, 2008-09-01)
Poly(9-fluorenecarboxylic acid) (PFCA) was synthesized by electrochemical oxidation of 9-fluorenecarboxylic acid (FCA) using a mixture of nitromethane and boron trifluoride diethyl etherate as the solvent and tetrabutylammonium tetrafluoroborate as the supporting electrolyte. An insoluble and conducting brownish-orange film was deposited on the electrode surface, both during repetitive cycling and constant potential electrolysis at 1.15 V. Characterization of the polymer film has been carried out using Four...
Citation Formats
B. Akgun, H. E. ÇAMURLU, Y. A. Topkaya, and N. SEVİNÇ, “Mechanochemical and volume combustion synthesis of ZrB2,” INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, pp. 601–607, 2011, Accessed: 00, 2020. [Online]. Available: