Abstract

In the traditional high pressure, high temperature (HPHT) process for diamond synthesis a great deal of research went into selecting the optimum alloys for diamond growth. By and large combinations of 3d and 4d transition metals proved to be the best. Copper, silver and gold seemed to have been contra-indicated during many decades of HPHT research.

For the LPSSS process in trying to establish the parallelism with HPHT we have now examined many metals, including the noble metals, rare earths, carbide and noncarbide formers, Pb, Sn, Bi, Sb, etc. Very interesting sequences of precipitations of diamond result from Ag and Au, and of course Cu and Ni. Metastable metallic (Me_xC_yH_z) liquid droplets (tens of microns in diameter) are formed containing up to 60-70% of C and presumably substantial H°. These droplets precipitate diamond from the Me_xC_yH_zliquid starting at the surface but going through the body.

© 1995 Optical Society of America