I need to use a foil with thermal stability up to the 1500 C and with relatively low price.I want to sinter some ceramic samples in air at 1500 C. To prevent evaporation of Li component from samples during sintering, I want to put the samples in a closed foil/envelop. Pt foil is suitable for me but It is too expensive. Foil thickness and it's purity are not important factor for me.
Hello,
Does this *have* to be a foil, and is the damage that is likely to occur arising from oxidation?
(in other words, would a chunk of graphite in a hard vacuum be suitable?)
Feel free to describe the situation more thoroughly, otherwise it would seem that Pt is the best solution.
Sometimes scrap foil appears on eBay:
http://www.ebay.ca/itm/Platinum-Foil-/231466546299?pt=LH_DefaultDomain_0&hash=item35e47b347b)
Hello,
Perhaps you can put your sample inside an alumina crucible, with an alumina tap. Between the crucible and the tap, some alumina powder to seal the sample container (crucible+tap)
Inside the crucible, some Li compound to generate enough Li vapor pressure that impedes Li going out from your sample.
Nevertheless 23 %Al2O3- 77%Li2O (mol %) forms an euthetic at 1055C, thus some care must be taken.
For example to impede that your sample gets sintered to the crucible you can also use some Alumina powder.
Regards, Miguel
Dear Ahmad! Hi! Metal needed you do not exist. There niobium-based alloy, but it is brittle (Nb-89 mol, Hf-10 mol, Ti-1 mol). Option with the crucible most suitable and reasonably cheap.
Regards, Nik.
In my opinion, the best solution of your problem is a graphite crucible (covered by bakelite) with graphite sealed (also with bakelite) lid. You will be able to use it even in air flow at temperatures up to 2000 oC. I had some experience with similar constructions in rocketry practice. Only be careful with CO and bakelite destruction products release!
Have you ever heard of Nextel cloth or alumina cloth. What thickness you are looking for in a foil? The alumina fibers woven into cloth form would be the best in my opinion. No oxidation and thermal stability.
Graphite doesn't work in air at 1500C. It will be burnt out; but it works in vacuum.
Mo foil is another option. But Mo suffers from fast grain growth and becomes brittle shortly. Ceramics should work in general, but you need to consider whether they contaminate your samples.
Ceramic cloth such as Alumina does not de gas. Talk to Zircar in the USA.
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