Need explanation for melted alumina lining in lab muffle furnace
Need explanation for melted alumina lining in lab muffle furnace
(OP)
Please provide possible explanations for following scenario:
During a routine lab procedure, the alumina-based lining in a countertop muffle furnace we use for burning off liquid asphalt binder incurred three small holes by what appears to be melting. The fuses did not blow, and the lab's circuit breaker did not trip. The manufacturer of the furnace informed us that the lining has a melting temperature of 3800C, well above the maximum operating temperature of 2000C.
Please see attached photo. Coil diameter < 1cm.
During a routine lab procedure, the alumina-based lining in a countertop muffle furnace we use for burning off liquid asphalt binder incurred three small holes by what appears to be melting. The fuses did not blow, and the lab's circuit breaker did not trip. The manufacturer of the furnace informed us that the lining has a melting temperature of 3800C, well above the maximum operating temperature of 2000C.
Please see attached photo. Coil diameter < 1cm.





RE: Need explanation for melted alumina lining in lab muffle furnace
RE: Need explanation for melted alumina lining in lab muffle furnace
If you get some arcing or corona you can melt the surface of the alumina and then it is electrically conductive enough to continue the process.
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