We have investigated the changes in the electronic structure of molecu larly adsorbed orthocarborane fi lms, as a function of Hg co-adsorption, using photoe mission. The interaction between Hg and molecular orthocarborane is weak and results in the formation of some small aggregates of Hg. This behavior is very different from alkali metals interaction with molecular carborane fi lms and the int...

Sintering with low frequency rf power (-50 M H z ) is a new technique with unique capabilities that has been used to sinter a variety of ceramic materials, including zirconia-toughened alumina, alumina, silicon carbide, and boron carbide. Processing with low frequencies offers many advantages compared to processing with conventional microwave frequencies (915 MHz and 2.45 GHz). Because of the l...

Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes is capable of storing hydrogen with a mass density higher than 6.0 weight% and a volumetric density higher than 45 g/L. The boron substitution in carbon nanotube greatly enhances the binding energy of Li atom to the nanotube, and this binding energy (~ 2.7 eV) is greater than the cohesive energ...

Recent observations of planar defects in boron carbide have been shown to deviate from perfect mirror symmetry and are referred to as "asymmetric twins." Here, we demonstrate that these asymmetric twins are really phase boundaries that form in stoichiometric B(4)C (i.e., B(12)C(3)) but not in B(13)C(2). TEM observations and ab initio simulations have been coupled to show that these planar defec...

In this study, mechanochemcical process(MCP) is applied to synthesize ultrafine TaC powders. In this research, nano powder composite TaC-TaB2 was produced using mixtures of tantalum carbide and boron carbide as raw materials via mechanochemical process. The phase formation characterization during process was utilized by X-ray diffractometry (XRD). The morphology of synthesized powder was studie...

In this paper, new various morphologies of boron carbide were successfully synthesized using carbon black, activated carbon and boron oxide precursors as well as using cobalt nanoparticles as catalysts. Almost the whole morphology of synthesized boron carbide are consisted of smooth nanowires and nanobelts. With decreasing the carbon black particles size from 29 nm to 13 nm (29, 23, 17 and 13),...

The discoveries of superconductivity in heavily boron-doped diamond, silicon and silicon carbide renewed the interest in the ground states of charge-carrier doped wide-gap semiconductors. Recently, aluminium doping in silicon carbide successfully yielded a metallic phase from which at high aluminium concentrations superconductivity emerges. Here, we present a specific-heat study on superconduct...

boron carbide is one of the hardest materials. the combustion method was used to synthesize b4c-tib2 nanocomposite powder in a b2o3-mg-tio2-c system. an experimental study of the formation of b4c–tib2 nanoparticles was conducted in the thermal explosion mode. a mixture of b2o3:tio2:mg:c at a molecular ratio of 3:1:12:1 was chosen to obtain the b4c–tib2. this powder mixture was milled for differ...