Thermodynamics of Crystallizing Low-Alloy Boron Steel Melt Components Interaction

Thermodynamic analysis of the phase equilibria in the Fe–Mn–Cr–Si–Al–Ti– Ni–V–Mo–B–S–P–C–N–O system at fixed concentrations of boron, manganese, chromium, silicon, aluminum, titanium, nickel, vanadium, molybdenum, sulfur, phosphorus, carbon and nitrogen was performed. Formation of nonmetallic phases upon cooling and crystallization of liquid metal solutions of various compositions was studied. It was established how aluminum and nitrogen content in the liquid metal solution affects the composition and amount of separated excess phases. Calculations demonstrated that boron nitride was not formed in the liquid metal and during crystallization.

Synthesis of Metastable Diamond

ABSTRACTDiamond can be grown as an equilibrium phase from a liquid metal solution containing carbon at high pressures and high temperatures. Diamond can also be grown as a metastable phase at subatmospheric pressures and moderate temperatures from hydrocarbon gases in the presence of atomic hydrogen. Atomic hydrogen serves several critical roles in CVD diamond growth, namely: 1) stabilization of the diamond surface, 2) reduction of the size of the critical nucleus, 3) “dissolution” of carbon in the gas, 4) production of carbon solubility minimum, 5) generation of condensable carbon radicals in the gas, 6) abstraction of hydrogen from hydrocarbons attached to surface, 7) production of vacant surface sites, 8) etching of graphite, 9) suppression of polycycic aromatic hydrocarbons. A search for substitutes for atomic hydrogen have been unsuccessful to date but several new processes that do not use atomic hydrogen are currently under study.

Liquid Bismuth Calorimetry: Enthalpies of Solution of Copper, Indium, and Tellurium, and Enthalpies of Formation of Cuprous Selenides

An isoperibol liquid metal solution calorimeter in which samples are introduced below the surface of the melt is described. Enthalpies of solution in liquid bismuth at ca. 625°K in kcal mol−1 were found to be +0.99 ± 0.05 for copper, −1.41 ± 0.08 for indium, and −1.16 ± 0.07 for tellurium.Enthalpies of formation in kcal mol−1 at 625°K of cubic cuprous selenides are −7.98 ± 0.20 for Cu1.80Se; −7.80 ± 0.19 for Cu1.85Se; −5.92 ± 0.20 for Cu1.90Se; −5.29 ± 0.20 for Cu1.95Se; and −5.21 ± 0.14 for Cu2.00Se.