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...

Nanocomposites based on boron carbide B4C are hard materials with wide field of applications in modern technologies. A system first-order ordinary differential equations that simulates the process chemical synthesis nanopowders B4C–TiB2 compositions containing titanium diboride (TiB2) as an additional phase is suggested and resolved numerically for a typical ratio reaction constants. Reagents p...

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...

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...

Disordered structures of boron nitride (BN), graphite, boron carbide (BC), and boron carbon nitride (BCN) systems are considered important precursor materials for synthesis of superhard phases in these systems. However, phase transformation of such materials can be achieved only at extreme pressure-temperature conditions, which is irrelevant to industrial applications. Here, the phase transitio...

The properties, applications and methods for producing titanium vanadium diborides are considered. These oxygen-free refractory metal-like compounds. As a result, they characterized by high values of thermal electrical conductivity. Their hardness is relatively high. Titanium exhibit significant chemical resistance in aggressive environments. For these reasons, have found application modern tec...

The study presents a possible mechanism to produce carbides and diborides of transition metals, such as titanium, vanadium, chromium zirconium. carbothermal synthesis metal has defined the direct dependence between thermodynamic stability oxides temperature range reduction onset (the stronger oxide, higher value is). It reaches 2000-2100, 1500-1600, 1300-1400 2100-2200°C for TiC, VC 0,88 , Cr 3...