Direct Conversion of Graphite to Diamond in Static Pressure Apparatus.

Static pressure apparatus has been developed which is capable of pressures up to 200 kbar and transient temperatures up to about 5000°K, using an electric flash‐heating technique. At pressures above about 125 kbar and temperatures in the 3000°K range it is found that graphite spontaneously collapses completely to polycrystalline diamond which may be retrieved quantitatively. The threshold temperature of the transformation is several hundred degrees lower than the melting temperature of graphite. The diamond/graphite/liquid triple point is found to be located at about 125 (+10, —0) kbar and 4100 (±200)°K. The shock compression results of DeCarli and Jamieson, and of Alder and Christian, are linked with the present results to construct a phase diagram of carbon extending to 5000°K and 800 kbar.

[1]  F. Bundy,et al.  Melting Point of Graphite at High Pressure: Heat of Fusion. , 1962, Science.

[2]  H. G. Drickamer,et al.  Pressure induced phase transitions in silicon, germanium and some III–V compounds , 1962 .

[3]  B. Alder,et al.  BEHAVIOR OF STRONGLY SHOCKED CARBON , 1961 .

[4]  A. Jayaraman,et al.  Melting and Polymorphism of Indium Antimonide at High Pressures , 1961, Nature.

[5]  F. Bundy,et al.  Diamond‐Graphite Equilibrium Line from Growth and Graphitization of Diamond , 1961 .

[6]  P. Decarli,et al.  Formation of Diamond by Explosive Shock , 1961, Science.

[7]  F. Bundy.  Calibration Techniques in Ultrahigh-Pressure Apparatus , 1961 .

[8]  H. G. Drickamer,et al.  High Pressure Electrical Resistance Cell, and Calibration Points above 100 Kilobars , 1961 .

[9]  H. T. Hall.  Ultra‐High‐Pressure, High‐Temperature Apparatus: the ``Belt'' , 1960 .

[10]  F. Bundy,et al.  Preparation of Diamond , 1959, Nature.

[11]  D. H. Everett.  Industrial Carbon and Graphite , 1958, Nature.

[12]  H. T. Hall.  The Melting Point of Germanium as a Function of Pressure to 180,000 Atmospheres , 1955 .

[13]  F. Bundy,et al.  Man-Made Diamonds , 1955, Nature.

[14]  P. W. Bridgman.  An Experimental Contribution to the Problem of Diamond Synthesis , 1947 .

[15]  P. Günther,et al.  Untersuchungen zum Diamantproblem , 1943 .

[16]  P. W. Bridgman.  Explorations toward the Limit of Utilizable Pressures , 1941 .

[17]  J. Basset.  Fusion du graphite sous pression d'argon de 1 à 11 500 kg/cm2. Détermination du point triple et établissement d'un diagramme provisoire des états solide, liquide et gazeux du carbone. I , 1939 .

[18]  P. W. Bridgman.  Polymorphism, Principally of the Elements, up to 50,000 kg/cm 2 , 1935 .

[19]  C. Parsons.  Bakerian Lecture, 1918: Experiments on the Artificial Production of Diamond , 1920 .