Carbon Vapor Pressure in the Range 3450 to 4500 K and Evidence for Melting at Approximately 3800 K

摘要

The vapor pressure of carbon was determined over the temperature range 3470 to 4490 K by using a laser heating technique. The solid-liquid-vapor triple point was located at approximately 3800 K and a pressure of approximately 13,000 Pa, and the normal boiling point was found to be approximately 4140 K. Evidence for a solid-solid-vapor triple point was found at approximately 3560 K. Liquid carbon was produced in a free state, and some of its properties were determined. Superheated liquid carbon was produced at low pressure by using sufficient laser power. Spectroscopic methods were used to determine the carbon gas temperature and as a cross-check on the temperature determined by an optical pyrometer. (Author)