On Wed, 8 Feb 2017 07:31:39 -0500, "Mr. Luddite" wrote:

On 2/7/2017 4:16 PM, Bill wrote:


Thought of you the other day while reading newspaper article on man made
diamonds. The company learned the process while doing solar cells. Use a
plasma to create diamonds same as nature, one molecule at a time.



I worked on a project and built a research system for creating
polycrystaline diamond films. Also worked on a project with (at the
time) a more practical use ... hard carbon films. Process is similar
although I am sure people have developed more efficient ways of doing it.

Basically, a substrate (object on which the film is to be deposited) is
put in a vacuum chamber, air is removed and then a partial pressure of a
hydrocarbon gas is maintained. An RF power supply is used to
disassociate the gas (usually methane), breaking it down to it's
chemical components. The hydrogen in the gas burns off weakly bonded
carbon atoms and a thin diamond film can result (if you have all the
parameters correct).

The diamond films really weren't good for optics at the time but they
were used as heat sink surfaces things like high density computer CPUs.

Strange thing about diamond ... it's a perfect electrical insulator but
is also an extremely efficient heat transfer material. I don't know of
any other material like that.

If you'll send me a few 2-3 carat diamonds, I'll try to test a few materials to see if I can find
something like that.