Improved Process for Synthetic Diamond Production

Synthetic diamonds catch the public’s attention because they immediately think of the man-made diamonds replacing diamonds in the jewelry industry.  However, the motivation behind researchers usually has more to do with industrial applications.  Diamond’s hardness, high thermal conductivity, high electrical resistivity, optical transparency, resistance to chemicals, and other unique properties make it a valuable material for a variety of uses including surgical scalpel blades, equipment “windows” exposed to harsh environments, heat-spreaders for electronic devices, temperature and pressure sensors, and drill bits used in mining and oil exploration.

Scientists at the Carnegie Institution‘s Geophysical Laboratory recently announced an enhanced process for growing diamond crystals using the chemical vapor disposition (CVD).  Most synthetic diamond methods require high temperature and extremely high pressure to mimic nature’s own diamond growing process.  However, the CVD process uses high temperature but low pressure to produce single-crystal diamonds rapidly and with more controlled results.

The Carnegie researchers add a new twist to the synthetic diamond process by heating the diamonds at temperatures up to 2000 degrees Celsius but low (less than atmospheric) pressure to alter the color of the diamond.  The raw synthetic diamond crystals are usually yellow-brown in color but this special annealing process transforms the color to a colorless or light pink hue.  With the ability to use low pressure, researchers have been able to identify the specific crystal defects that cause color changes in diamonds.

This annealing process uses microwave plasma to produce the high heat at low pressure, yet keeping the diamond from changing to graphite.  Producing colorless diamonds has been a challenge for synthetic diamond manufacturers and getting a faint pink color could end up being a bonus.  This ability to produce colorless diamond crystals has value not only in the jewelry industry but also in many of the industrial applications where colorless transparency has increased value.

Comments

[Reeta]

A high purity synthetic diamond with less impurities, crystals defects, strains, etc. Can be provided,in which the nitrogen content is at most 10 ppm, preferably at most 0.1 ppm and the boron content is at most 1 ppm, preferably at most 0.1 ppm or in which nitrogen atoms and boron atoms are contained in the crystal and the difference between the number of the nitrogen atoms and that of the boron atoms is at most 1×1017 atoms/cm3. The strain free synthetic diamond can be produced by a process for the production of a strain free synthetic diamond by the temperature gradient method, which comprises using a carbon source having a boron content of at most 10 ppm and a solvent metal having a boron content of at most 1 ppm and adding a nitrogen getter to the solvent metal, thereby synthesizing the diamond.
-----------------------------------
Reeta

diamond earrings

[Synthetic Diamonds]

Wow!

It is good to see so many people taking initiative and giving us a good information on synthetic diamonds. Thanks for sharing it.

Most synthetic diamonds in the market today are made up of cubic zirconia or moissanite. With the rapid growth of the diamond industry, some companies have already discovered new materials that can be used as simulants which are better than moissanite. Manufacturing of diamonds has gone to the next level and has become more realistic with the natural diamonds.

================
Denny's Response:
While the person submitting the comment above works for the Sona Diamond Company, their misleading use of the word "synthetic" is an example of how they market products like the "Sona Diamond" brand of CZ. Cubic Zirconia and Moissanite are diamond simulants and are not synthetic diamonds. To imply that brands of CZ are synthetic diamonds is misleading and deceptive advertising.