Novel Diamond Synthesis Routes

The graphite-diamond equilibrium line in Fig. 7 is based on a thermodynamic ana- 

2 Increase in Enthalpy Synthesis from Nongraphitic Carbons 

The possible success of a synthesis route using nongraphitic carbon would seem to depend upon the suppression of graphite nucleation and purity factors, since growth of high quality diamond requires low levels of impurities. This is more difficult to achieve in a carbon which has not been graphitized. 

3 Interfacial Energy Growth in the Colloid Size Range 

In practice, these solid-vacuum interfacial energies are not likely to be seen, since the diamond surface and the graphite prism-face surfaces will reconstruct or react with adatoms such as hydrogen and oxygen to reduce their surface energy. Under atmospheric conditions, diamond is terminated by a range of hydride and oxide 

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There is understandably some pessimism regarding a commercial synthesis of superhard carbon nitride especially in view of the intense effort that has been put into its synthesis by many laboratories in the last few years with no firm result to date. Yet the wisdom of the computational arguments upon which the various structures of the material have been predicted seems firm and they have been shown to be capable of giving us valuable insight in many other areas of materials science. Experiences gained regarding the commercial synthesis of diamond and cubic BN could probably lead ways that carbon nitride can be synthesized, yet other more novel routes also cannot be excluded. 

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