bobulus31

https://www.jstage.jst.go.jp/article/cl/34/12/34_12_1620/_article Stumbled across this last night. Looks like an aluminum oxide crucible might work fine with a seed crystal. I might end up breaking the crucible getting it out but i can get those all day for 30 bucks.

Yeah everything else about it seems perfect. Price is right there with the tungsten though, so if tungsten would do it in open air without reacting i would rather use that. Thank you guys for all the information by the way, its been a huge help.

Well the crucible should really only need to handle about 1200c since the molybdenum trioxide lowers the melting point of alumina to about 1100c. I would like to not have to use a vacuum if possible but I suppose that is the least of my worries. The glassy carbon looks promising as i doubt it is going to react with any of the chemicals but it only works in open air up to 500c according to the site. That is why I was hoping to use tungsten, however from what I have seen it may react to the molybdenum trioxide. I do not know that for certain though. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422010000500018 (sorry i could only find the full document in Portuguese) This is the main document I have been working off of in my efforts. I just do not have the funds currently to purchase even the smallest platinum crucible.

Hmmmm. Any idea if Molybdenum Trioxide would react with a tungsten crucible? If not, then I would imagine the same process that is done in the platinum crucible could be done in a tungsten one.

Ahhh darn. And I have looked into that and the Czochralski process but the gems they create end up more like a really hard glass than an actual ruby. I have heard that growing the gems in flux or hydro-thermally creates crystals that shine much more brilliantly which is what I'm looking for. I've been looking into tungsten and Inconel crucibles since they can stand the heat required, i just don't know for certain whether either one would react with the alumina or whatever flux I use.

I'm trying to crystallize different corundum gems. The corrosive properties wont bother me too much as long as the corundum is able to crystallize properly. I'll definitely look into the sodium hydroxide and nickel combo tho. Thanks for the info. If anyone else has other possible ideas id love to hear them. The process I have heard that works is dissolving the alumina in molybdenum oxide inside a platinum crucible and heat to about 2100 degrees F. then slowly lower the temperature by a couple degrees per hour to get the alumina to crystallize into corundum such as ruby.

Hello everyone, I have a few questions. First of all, I'm looking to melt Al2O3 in a flux in a crucible. I was wondering what would be the best combination of crucible lining and flux to do so at the lowest possible temperature. I know that it can be done in a platinum crucible quite easily but i don't exactly have 5 grand to throw down on a crucible so if anyone knows if this is possible or even theoretically possible in any less expensive apparatuses i would love to hear from you. Thanks a ton in advance.