Melting point variation with pressure and material synthesis by a laser heated diamond anvil cell

The details of a high temperature-high pressure (HT-HP) facility based on the coupling of the laser heating by diamond anvil cell are described. The measured melting curve of platinum up to 12 GPa pressures is compared with existing pistoncylinder data and with theoretical calculations. The reasonable agreement reveals the utility of this technique for the reliable measurements of high temperature-high pressure phase diagrams and melting curves for materials. The suitability of hexamethylenetetramine (HMT) as a precursor for the synthesis of C ₃N ₄ at HT-HP, has been investigated. It is conjectured that CN _x (C ₃N ₄) or C:H is formed at HT-HP, but is not quenchable.