Phase diagrams of refractory metals remain essentially unknown. Moreover, there is an ongoing controversy over the high-pressure melting temperatures of these metals: results of diamond anvil cell (DAC) and shock wave experiments differ by at least a factor of 2. From an extensive ab initio study on tantalum we discovered that the body-centered cubic phase, its physical phase at ambient conditi...

Over the last 20 years, great progress has been made in techniques for electrostatic levitation, with innovations such as containerless thermophysical property measurements and combination of levitators with synchrotron radiation source and neutron beams, to name but a few. This review focuses on the technological developments necessary for handling materials whose melting temperatures are abov...

An improved technique is described for the accurate determination of melting points of metals in the temperature range 1500° to 2500°C. The improvements consist of gradient heating and refinements in cavity preparation to obtain true black-body conditions. The melting point of hafnium, as determined by this method, is set a t 22220-+30°C. This is over 200°C higher than one of the values reporte...

We discus existent conflicts between experimentally measured and theoretically calculated melting curves of Mo, Ta, and W. By assuming that vacancy formation plays a fundamental role in the melting process, an explanation for the measured melting curves is provided. Furthermore, we show that the Lindemann law fits well all the measured melting curves of bcc transition metals if the Grüneisen pa...

NMR was used to study the effect of melting on the electronic structure of copper and aluminium. The Knight shift and spin—lattice relaxation time were measured as a function of temperature in the solid and in the liquid state. From these measurements the temperature dependence of K(x). the reciprocal enhancement factor of the Korringa relation, is obtained. In the case of copper it is shown th...

By investigating the effects of the configurational entropy, the vibrational entropy and the bonding strength of solid-liquid atoms on the structure of solid-liquid interface, a model for the interface energy of rough solid-liquid interface has been developed. From present model, the non-dimensional solid-liquid interface energies for metals at melting point are predicted to be 0.66–0.73, which...

industrial processes release a range of gaseous and particulate pollutants containing heavy metals into the air. lack of enough attention to the design, installation, repair and maintenance of gas and dust filtration systems in industries, is one of reasons of increasing the emissions of these pollutants. hereon, the steel making processes is one of emission sources of heavy metals. according t...

The melting point of palladium was determined by measuring with an optical P3^rometer the ratio of brightness of the red light (X= 0.6528m) emitted by black bodies at the melting points of palladium and gold, respectively. The crucible method was shown to be more reliable than the wire method. Especial attention was given to the purity of the metals. The result obtained by the crucible method, ...