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Author: Subject: in which way could diamond powder/dust be turned solid
13enigma
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[*] posted on 10-8-2017 at 16:46
in which way could diamond powder/dust be turned solid


I see online that diamond powder is sold. Which is pretty much just carbon. But how could the powder form be reverted back into solid. I realize that it will not be "beautiful engagement ring diamonds" but I was curious behind this chemical process and physical change
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Chemetix
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[*] posted on 10-8-2017 at 23:50


One technique can be attributed to a Ferris Bueller.

https://www.youtube.com/watch?v=O42K4EwVssQ

Otherwise the principle is sound. Extreme pressure and heat is used.
Iirc, the modern synthetic approach also uses an electrical field and some water during the process.
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13enigma
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[*] posted on 11-8-2017 at 09:45


An electrical field and water?
Like electrolysis??
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[*] posted on 11-8-2017 at 10:07


I've heard that sodium nickelate has been used to recrystallize diamonds. http://www.sciencedirect.com/science/article/pii/09259635949...
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13enigma
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[*] posted on 11-8-2017 at 10:36


Yeah this idea is very interesting. I saw videos of salt being crystallized into a diamond shaped figure. I was interested in doing this with the diamonds powders I have now. I understand that carbon is different from NaCl. But the idea was there
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[*] posted on 11-8-2017 at 15:00


I understand the the electric field is used to orient the di-poles of the forming carbon lattice so to maintain the diamond structure, water I think acts as a sort of solvent, probably for the electrons to move around bit before forming the c-c bond. The use of electrical charge is about where the similarity to electrolysis ends.

The rest is some pretty exotic hardware of extreme hydraulic presses with heated cores and some very specifically engineered dies for the gem formation. A backyarder $5 budget isn't going to consolidate diamond powder to any quantity.

Implosive forming using HE shaped charges or explosive lenses might get a few lumps to stick together. You might need an outer shell of, say, salt to act as a buffer to the expansion phase of the shock; to keep the formed diamond from being ripped apart again.... just a thought bubble at this stage.
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Melgar
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[*] posted on 11-8-2017 at 21:19


The short answer is that you can't. Unlike many other materials, you can't melt down diamonds and combine them to make larger ones. It's sort of like wood in that respect. You can glue together sawdust to get particle board, but it won't have nearly the strength as regular wood.

edit: You can get 2-3 carat rough industrial diamonds for $10-$20 on eBay. If a diamond is below gemstone quality, its price is dramatically lower:

https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&L...

Usually the auctions, as opposed to the "Buy it Now" listings are cheaper, if you don't mind waiting.

[Edited on 8/12/17 by Melgar]




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13enigma
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[*] posted on 12-8-2017 at 12:24


So, you're saying that a diamond powder similar, to saw dust, can not be clumped back together to form a bigger solid?
How?
I see that carbon powder like graphite can be turned back into solid. I've seen 99% Graphene crucibles too. Correct me if I'm wrong on this.
Thanks
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ELRIC
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[*] posted on 12-8-2017 at 17:36


Quote: Originally posted by 13enigma  
So, you're saying that a diamond powder similar, to saw dust, can not be clumped back together to form a bigger solid?
How?
I see that carbon powder like graphite can be turned back into solid. I've seen 99% Graphene crucibles too. Correct me if I'm wrong on this.
Thanks


You do know that you're "carbon powder" is in fact a solid. Just like the NaCl you

likely have in you're kitchen is a solid. I'm with Melgar on this one. If it were not

so, wouldn't the value of diamonds drop like a rock (pun intended)
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13enigma
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[*] posted on 12-8-2017 at 17:55


I know it's a solid.
I just meant that the powder would need to agglomerate into a bigger cohesive solid
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elementcollector1
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[*] posted on 12-8-2017 at 17:59


Quote: Originally posted by 13enigma  
So, you're saying that a diamond powder similar, to saw dust, can not be clumped back together to form a bigger solid?
How?
I see that carbon powder like graphite can be turned back into solid. I've seen 99% Graphene crucibles too. Correct me if I'm wrong on this.
Thanks


Please research the difference between a sintered product and a solid one.




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unionised
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[*] posted on 13-8-2017 at 04:14


In principle it's perfectly simple; you melt the diamond powder the let it cool down and set into a single diamond.
However the temperatures and pressures required make it practically impossible.
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LD5050
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[*] posted on 13-8-2017 at 06:52


Just curious but exactly what are the temps and pressures needed?
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[*] posted on 13-8-2017 at 12:44


@LD5050 Straight from the wiki. https://en.wikipedia.org/wiki/Synthetic_diamond

Norton and Carborundum companies to further develop diamond synthesis. They were able to heat carbon to about 3,000 °C (5,430 °F) under a pressure of 3.5 gigapascals (510,000 psi) for a few seconds.

I would assume the process of fusing smaller diamonds would follow along the same lines.

However i recently found the following which seems to suggest that the guys at the carnegie institute in washington manage to succeed at much lower pressures.
The idea follows the same general anvil process however instead of using graphite as there carbon source they use methane and pass an ionized hydrogen plasma through it.
I don't have any info as to the exact design of this process however.
http://cen.acs.org/articles/90/i11/Carbon-Goes-Deep.html
https://www.youtube.com/watch?v=A4_l3pKhaJo
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13enigma
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[*] posted on 15-8-2017 at 13:41


Quote: Originally posted by unionised  
In principle it's perfectly simple; you melt the diamond powder the let it cool down and set into a single diamond.
However the temperatures and pressures required make it practically impossible.


Yeah, in principle it sounds so simple. But so much difficult to do. I'm convinced that an amateur hobbyist chemist ad myself can't do it with regular tools. I'm gonna need industrial equipment with safety precautions in a lab.
But I saw a video of a guy making salt crystals in diamond shape with water and some other inorganic salts. That's is not possible to do with Diamond powders right? I'm assuming because of their difference in elemental status
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Assured Fish
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[*] posted on 15-8-2017 at 21:00


@13enigma it fucken took you long enough.
Quote:

But I saw a video of a guy making salt crystals in diamond shape with water and some other inorganic salts. That's is not possible to do with Diamond powders right? I'm assuming because of their difference in elemental status

You astound me with your complete lack of knowledge on the subject of chemistry.
NaCl is an ionic salt that is highly soluble in a range of solvents, therefore it can be recrystallized.
Diamonds are an allotrope of carbon.
Carbon is pretty much insoluble in just about everything (atleast i cannot think of anything it is soluble in).
Diamonds despite there appearance are not the same as crystals, it is fucken imperative that you get this through your thick skull.

If you have any legitimate passion for chemistry then i implore you to please go pick up a basic high school chemistry textbook and read it front to back before you even attempt to think about trying to conduct any amateur chemistry.
Now let this insanity be over.
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[*] posted on 15-8-2017 at 21:27


Agreed, AF. This line of questioning is at the extreme basic end of chemistry and displays a fundamental misunderstanding of some elementary principles. I have to wonder what the specific interest in diamonds is given the lack of knowledge here.


So... here are some basics. Bonding.

There exist several main mechanisms by which atoms may be bonded together. Here is an oversimplified summary.

Ionic -- a bond between a non-metalic element and a metallic element.
In this mechanism the metallic atom loses an electron and thereby becomes positively charged. At this point it is called an ion: specifically, a cation.
The non-metallic atom gains that electron and becomes a negatively charged ion: an anion.
The positive and negative ions then stack together in a regular lattice and are held in stable configuration by electrostatic attraction. This is known as a crystal of an ionic solid.

Metallic -- a bond between (usually identical) metal atoms.
In this mechanism all of the atoms involved lose electrons. The lost electrons are delocalised -- that is, free to move and not associated with any one particular atom. There is of course an electrostatic force of attraction between the positive cations and the mobile electrons. The system arranges in a stable configuration where the cations stack together in a crystal lattice and the electrons move freely through that lattice. The phrase generally employed to describe this is, "positive ions in a sea of electrons."

Covalent -- this is bonding between non-metallic elements (although there are many exceptions). In this configuration the atoms share electrons. In a normal atom the electrons occupy orbitals and essentially form a stable standing-wave shape centred around the nucleus of that atom. In a covalent bond the outermost or valence electrons form an orbital that is centred around the nucleus of two atoms. This turns out to be a very stable configuration since all the atoms involved can achieve a state where they effectively have a full outer shell.

Covalent bonding can give rise to two distinct structures: molecules and networks.
In a molecule a small number of atoms are attached to one another and the whole structure is free to operate as one unit.
In a network there is a rigid three dimensional network of bonded atoms. These forms some of the hardest and strongest materials known. Diamond is one of these.

All this should be taken with a grain of NaCl. there are no hard and fast boundaries between any of the categories I have mentioned. But this should at least answer your question. The situation has nothing to do with the "elemental status" of diamond. Rather it has everything to do with the type of bonding involved. And covalent bonding is the strongest bonding there is.

I concur with AF. it is time to get out a secondary school textbook and read the first few chapters.
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[*] posted on 15-8-2017 at 21:58


I suggest rubbing the diamonds together rapidly. the resulting heat from friction will fuse them together and maintain the crystal structure because they are bonded along the opposing faces.

[Edited on 16-8-2017 by diddi]




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[*] posted on 15-8-2017 at 23:06


Stop feeding this troll

It is this sort of mind numbing tat that makes me want to switch off

Even the tongue-in-cheek replies of my more erudite colleagues are a massive turn off
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physics inclination
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[*] posted on 16-8-2017 at 07:30


This is kind of a joke/"out-there" suggestion, but what if you tried detonating a shaped charge (no copper penetrator or anything, just explosive) onto graphite or diamond powder, where the "focus" of the blast is right on the powder?
That would be 1) certainly able to generate pressures high enough, or probably even higher than a solid lab apparatus and 2) somewhat accessible and relevant to users of this forum :P
edit: also keep in mind that this would (if it works at all) only produce lower-quality "sintered" diamond crystals rather than high-quality high-strength "cast" or "forged" diamond crystals--to use the analogy to how metal crystalline structures form differently depending on how they're made

[Edited on 8-16-2017 by physics inclination]

[Edited on 8-16-2017 by physics inclination]
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[*] posted on 16-8-2017 at 10:46


physics inclination, that does actually work. It has been the subject of serious research, no joke.
One can use explosives to make (very, very small) diamonds. Oxygen-deficient explosions of TNT have been shown to produce 'nano-diamonds' (just 10's of nm in size, but definately diamond phase).
I am too lazy to look up the papers right now, but no doubt google will easily find them.

Did mythbusters not also have an episode where they made diamonds large enough to be visible with explosive compression?




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physics inclination
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[*] posted on 16-8-2017 at 13:33


Quote: Originally posted by phlogiston  

Did mythbusters not also have an episode where they made diamonds large enough to be visible with explosive compression?


Found it yes :D
https://www.youtube.com/watch?v=0mWQUvxcANE
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[*] posted on 16-8-2017 at 14:42


Could you do CVD onto a surface covered in diamond powder and thereby bind them together?
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[*] posted on 16-8-2017 at 16:21


Quote: Originally posted by clearly_not_atara  
Could you do CVD onto a surface covered in diamond powder and thereby bind them together?

If you are going to sinter diamond particles then you have an alignment problem. You might get a cohesive mass (if you are clever) but you won't get a single crystal unless you are above recrystallisation temperature for long enough time. IOW, diamond dust is going to be a poor starting material if you want large diamonds.
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elementcollector1
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[*] posted on 17-8-2017 at 08:43


Come to think of it, why not just mix the diamond dust with a resin binder and create a 'druzy' that way? It'd still be gorgeous, and you wouldn't have to worry about high-tech methods to improve the diamonds' size.



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