I am sintering calcium silicate gel
when i put it on the aumina holder to be sintered at 1400C
the powder has attached to the alumina holder and can’t be separated
so what is the appropriate holder material to be used
ia it platinum or else?
1400°C in the air: only platinum or platinum-rhodium alloy. 1400°C under inert gas: graphite, molybdenum or tungsten.
I think your samples are getting melt at 1400C why they are attached with alumina crucible. You may reduce sintering temperature to get rid of this problem.
I will try using platinum one as it is the most inert and can withstand high temp
Of course, you can use platinum crucible in the case when your does not melt at high temperature.
Collet clamp is the sample holder in a solar furnace .
Refractory containers ( crucibles, capsules) are used in chamber furnaces with various environments (vacuum furnaces, resistance furnaces). The refractoriness of both crucibles and capsules is higher than the furnace operating temperature. Crucibles and capsules can also be used for the samples sintering in special bitstones.
if you think that Ca related sample melt at high temperature...better use Platinum crucible with lid. Or SiC crucible also works at high temperatures.
Mohamed
Platinum is too expensive. Try to give a coating of graphite to alumina crucible. It will work.
Dr.K
most specimen holders are made from aluminum (or sometimes even Kaolin which is a source of alumina elaboration). This material (alumina) when it is brought to high temperature (> 1200°C), it will be much favored to be diffused in all the materials which are in contact with it, this will lead to bonding between these materials (for example: Alumina - calcium silicate)
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