I've been using the same 1" tube furnace to carbonize my polymer nanofibers. I follow a typical protocol where I first stabilize the sample in a box furnace (in air) at 280 C then use the tube furnace under 60 sccm UHP N2 at 1000 C (ramp 5 C/min) for 1 hour. This gave me no problem before and only recently I started seeing 2 things:
1) no sample is left after carbonization. There are sometimes some white flakes left in the crucible, but my sample is supposed to be black after carbonization.
2) the outlet end of the tube is contaminated with some white material, I'm not sure what. The sample I start with is brown color.
I have a suspicion this started happening when we installed a metal gasket with rubber O-rings on both ends of the tube. Before, we just had a rubber stopper with glass tube going through to supply the gas. However, I'm not sure how that could remove all of my samples and contaminate the tube with white stuff.
Anyone have any insights on what could have happened?? Thank you!!
White stuff may be silicone dioxide, coming from the rubber maybe.
If there is no remaining sample after carbonization, maybe you have some problem with the stabilization process.
Thank you for your feedback! I didn't have any problem with this protocol before I installed the gaskets, though.. I didn't make any changes to the protocol except the tube furnace setup was altered with the metal gaskets. Would it be possible that is somehow causing the sample loss as well?
Is there a possibility for oxygen contamination inside the furnace? That would also kill your sample. E.g. the O-rings are not sealing as good as the old rubber stopper did.
Also, for Si to SiO2 oxygen is needed.
I think this is worth some investigation.
Nitrogen source is OK?
Infact, I stumbled into this as a result of my sample loss in the tube furnace as explained by Sooyoun Yu. I think I should apply some stabilisation firstly as she advised before taking to the tube furnace. I will like to know she finally solved the issue.
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