Изменение температуры плавления металлов с ростом давления

Abstract

A new analytical (i.e., without computer modeling) method for calculating the dependence of the melting temperature (Tm) of a single-component crystal on pressure (P) is proposed. The method is based on the delocalization melting criterion and does not contain fitting constants. The baric dependences of the melting temperature Tm(P) and its pressure derivative Tm(P) for gold, platinum and niobium in the pressure range: P = 0 – 1000 GPa were calculated by this method. It was shown that the dependences calculated by this method for gold and platinum agree better with the experimental data than the dependences obtained by computer simulation methods. For niobium, the calculated dependence Tm(P) turned out to be steeper, i.e., the value Tm(P) turned out to be larger than in the experiment. It was indicated that this discrepancy might be due both to a decrease in the Lindemann parameter with increasing pressure and to a redistribution of electrons on the s-d-orbitals during compression of transition metals with a BCC structure.