Alumina aerogel as refractory material

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The discussion centers on building a versatile forge for flux crystallization of corundum, specifically ruby and sapphire, with the capability to withstand temperatures up to 1400 C (2550 F) for extended periods. Key requirements include thermal resistance of at least 1 m2*K/W, the use of electrical resistance heaters like MoSi2, and a somewhat air-tight design for gas injection to manipulate the furnace atmosphere. The proposed insulation material is Al2O3 aerogel, valued for its thermal properties, which could provide adequate insulation without excessively thick walls. However, concerns are raised regarding the aerogel's performance at high temperatures, as a referenced study indicates potential sintering and reduced insulation value after exposure to temperatures near its limits. The discussion seeks insights on the suitability of aerogel for high-temperature applications and the overall forge design.
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I'm interested in building a forge, mainly for flux crystallization of corundum (ruby/sapphire), but I want it to be versatile.

General Requirements:
  • Withstand temperatures up to 1400 C (2550 F) for months at a time (crystallization can have very slow kinetics)
  • Walls with a thermal resistance of at least 1 m2*K/W
  • Electrical resistance heaters (MoSi2 or other)
  • Somewhat air-tight to allow for manipulation of furnace atmosphere through gas injection
  • Interior volume of ~8 cubic feet

Al2O3 has good thermal properties for my application, and I'm looking at lining my furnace with several inches of Al2O3 aerogel for use as insulation.

In fact, this is pretty much the only suitable material I've found that will give my furnace walls an acceptable thermal resistance without having to have walls that are 4+ feet thick.

Any thoughts on the suitability of aerogel as forge insulation, or on my plans in general?
 
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Forgot to include this link:

https://e-reports-ext.llnl.gov/pdf/242911.pdf

In this paper, the authors tested the properties of the al2o3 aerogel they synthesized, but not much over 1000 C. They mention that some sintering did occur at the upper bounds, which has me concerned that exposure to very high temperatures would reduce the aergoel's insulation value after several duty cycles.
 

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