Sciencemadness Discussion Board - Inorganic synthesis using Co2 laser.

Inorganic synthesis using Co2 laser.

Admagistr - 24-12-2023 at 18:54

For a long time I have been thinking about synthesizing corundum, ruby and blue sapphire using an infrared CO2 laser.I just didn't know how much power of a CO2 laser is needed for this.Recently I googled an interesting specific link on the topic.It shows that a 60W laser is enough,I thought that much more power would be needed,so I am pleasantly surprised.Here is the link:

https://laserpointerforums.com/threads/producing-synthetic-c...

I bought a laser tube from Vevor together with a power supply and HV cables,it was quite cheap.

https://eur.vevor.com/other-c_11229/60w-co2-laser-tube-60w-l...

I also bought a micro ampermeter,tube stands and a pump for water cooling,but Vevor doesn't offer all that.I had to turn to other sellers.I'm going to try it soon personally,I'll report back how the experiments turned out.

[Edited on 25-12-2023 by Admagistr]

chloric1 - 25-12-2023 at 09:33

Would be quiet the endeavor if you made Boron Nitride and then used that to put armor plating on your car.

Twospoons - 25-12-2023 at 13:35

I suppose its worth mentioning laser safety to casual passers by- especially with IR lasers (no blink reflex to save your eyes).

Keep the beam enclosed - it doesn't take much to stop a 60W 10.6um beam, but you really don't want that stop to be your eyeball. Beware of reflections. Add an interlock to your enclosure.

Treat the HV supply with respect - if it bites you it will definitely hurt, and is potentially lethal. 24kV will jump a 20mm airgap in the right conditions (eg humid, higher altitudes), and can go even further tracking across a surface. I've seen 25kV track over 150mm across Mylar (PET) sheet.

Looks like an interesting experiment. If you have the gear, then doing this under vacuum could be worthwhile - with no gas between the alumina grains I would expect better coalescence, maybe better clarity in the resulting gem.

[Edited on 25-12-2023 by Twospoons]

Admagistr - 25-12-2023 at 22:33

@Twospoons
Good that you wrote something about safety, better to hear such things several times than not to address them or forget about it.Yes, rubies, sapphires will certainly be of better quality than those produced in an autogenous flame or in an electric arc, there will be much less gas in them.I have been thinking about producing them in a vacuum since the beginning, but how to arrange the apparatus? If I put the mixture of reactants in a quartz reactor I don't know how to seal the reactor hermetically and at the same time let the IR beam penetrate into it.Could quartz glass be used?Is quartz glass transparent to the IR laser beam?Or is it necessary to use another material,but what material?NaCl which is used to make lenses for IR lasers?What do you think?

Twospoons - 26-12-2023 at 12:41

Quartz will not pass IR from a CO2 laser. Few materials are sufficiently transparent at 10.4um for CO2 laser work. For that you will need a window made of either zinc selenide or silicon. This should be readily available - there are a lot of CO2 laser optical components made from these materials. You will probably want to get a lens for beam focus too - also made or ZnSe or Si. A lens will let you control the optical power density at your melt point, and also makes stray beams safer as they will diverge faster and lose intensity quicker.

https://www.aliexpress.com/w/wholesale-znse-window.html?spm=...
Ideally get something with an anti reflection coating (better system efficiency, less stray beam to deal with.)

[Edited on 26-12-2023 by Twospoons]

Admagistr - 27-12-2023 at 21:38

Quote: Originally posted by Twospoons

Quartz will not pass IR from a CO2 laser. Few materials are sufficiently transparent at 10.4um for CO2 laser work. For that you will need a window made of either zinc selenide or silicon. This should be readily available - there are a lot of CO2 laser optical components made from these materials. You will probably want to get a lens for beam focus too - also made or ZnSe or Si. A lens will let you control the optical power density at your melt point, and also makes stray beams safer as they will diverge faster and lose intensity quicker.

https://www.aliexpress.com/w/wholesale-znse-window.html?spm=...
Ideally get something with an anti reflection coating (better system efficiency, less stray beam to deal with.)

[Edited on 26-12-2023 by Twospoons]

@Twospoon: Thanks a lot for the information!I was thinking about using a lens that scatters the IR rays so that they hit a larger area, but I would probably have to use a stronger laser and it would be more dangerous.Moreover, such lenses are probably not commonly sold.

Twospoons - 28-12-2023 at 13:38

I get the odd sense you are unfamiliar in working with lasers. Take extra care, check everything twice, especially when working with a 60W laser with an invisible beam. To put this in a chemistry perspective, any laser of more than a few mW power deserves the same sort of respect you would show a toxic gas: its invisible and can get you from across the room. Use the correct PPE and procedures and you will be fine. Unsure of something? Ask - don't guess. The laserpointer forum would be the best place to get solid advice.

I recently bought a 1W UV laser for a project. I also bought safety glasses that cost 4 times what the laser cost. I have yet to power it up, tempting as that is, because I have yet to build the thing its going in.

[Edited on 28-12-2023 by Twospoons]

Admagistr - 28-12-2023 at 15:19

Quote: Originally posted by Twospoons

I get the odd sense you are unfamiliar in working with lasers. Take extra care, check everything twice, especially when working with a 60W laser with an invisible beam. To put this in a chemistry perspective, any laser of more than a few mW power deserves the same sort of respect you would show a toxic gas: its invisible and can get you from across the room. Use the correct PPE and procedures and you will be fine. Unsure of something? Ask - don't guess. The laserpointer forum would be the best place to get solid advice.

I recently bought a 1W UV laser for a project. I also bought safety glasses that cost 4 times what the laser cost. I have yet to power it up, tempting as that is, because I have yet to build the thing its going in.

[Edited on 28-12-2023 by Twospoons]

Thanks for the warnings and advice and willingness to help!I have worked with He-Ne lasers in my studies at the Institute of Theoretical Physics and Astrophysics and solved pre-written problems. But it was only a short practical experience,we were warned then that before we could blink an eye,it might be too late.I know that a 60W CO2 laser is much more dangerous,so I will be more careful.At the Institute of Theoretical Physics there was only one pair of glasses available for a group of students,I asked for them at the time and the teacher mocked me a bit for overdoing it. One fellow student got a direct hit in his eye,because he was working inattentively.He said that since then he has a bit of a problem and he can't see as well as before,but I don't think he has taken it any further and hasn't been to the eye doctor.I don't remember what power was this He-Ne laser.

Twospoons - 28-12-2023 at 20:37

HeNe is usually only a few mW, up to maybe 50mW. I have a couple of 2mW HeNe lasers. Being visible, the blink reflex can reduce the eye damage risk, but as your classmate found out even these low-power lasers are not toys.
Glad you are taking this seriously.