Early diamond making at General Electric

This is an account of how GE’s early interest in a new super‐hard metal, cobalt cemented tungsten carbide, for drawing tungsten lamp filament wire, led to a broader interest in the realm of super pressure and to diamond synthesis. P. W. Bridgman at Harvard University had demonstrated the new metal’s (‘‘Carboloy’’) ability to generate pressures of 100 000 atm (100 kbars). Armed with this new capability, GE initiated a diamond project in 1951. In December 1954 two synthesized diamonds emerged in a marginal experiment that for a while could not be reproduced. Nevertheless, that experiment gave the critical clue to the process that now provides 90% of the world’s industrial diamond needs. The high‐pressure high‐temperature process (HPHT) together with the new carbon vapor deposition process (CVD) brings diamonds’ unique and valuable properties to applications requiring crystals tailored to fit specific needs.