Castable Refractory with high Thermal Conductivity

[Deleted]

Would it not be nice to have stove plates, which will not warp under high heat,
with a smoth and shiny surface in white or colored with any heat resistant pigment availabe,
or a barrel pleasing your wife ?

While geopolymers have a low thermal conductivity by nature
it is not hard to make geopolymer concretes with high conductivity.

Superplasticizers can be used to reduce water demand
and thus porosity.

Minerals with high thermal conductivity eg. corundum or silicon carbide
can be used as aggregate to enhance thermal conductivity a huge lot.

A scientiest claims he has got plastic to 40 W/mK with cubic boron nitrite.

For maximal thermal conductivity one needs medium, fine and very fine aggregate.

The simplest way to find the best ratios of the three particle sizes
is to place the medium particles in a container on a vibrating table
and add slowly as much of the fine particles as is possible without
changing the volume occupied by the medium particles.
Repeat the procedure with the very fine particles.
If you have measured the weights you can calculate the ratios.




Enhanced Thermal Conductivity of Polymer Composites Filled with Hybrid Filler
www.researchgate.net/publication/257544414_Enhanced_Thermal_Conductivity_of_Polymer_Composites_Filled_with_Hybrid_Filler

ENHANCED THERMAL CONDUCTIVITY OF EPOXY MATRIX COMPOSITES FILLED WITH BORON NITRIDE PARTICLES
www.iaeme.com/MasterAdmin/UploadFolder/ENHANCED%20THERMAL%20CONDUCTIVITY%20OF%20EPOXY%20MATRIX%20COMPOSITES%20FILLED%20WITH%20BORON%20NITRIDE%20PARTICLES/ENHANCED%20THERMAL%20CONDUCTIVITY%20OF%20EPOXY%20MATRIX%20COMPOSITES%20FILLED%20WITH%20BORON%20NITRIDE%20PARTICLES.pdf

The effects of particle size and content on the thermal conductivity and mechanical properties of Al 2 O 3 /high density polyethylene (HDPE) composites
www.expresspolymlett.com/letolt.php?file=EPL-0002172&mi=cd

EFFECT OF FILLER SIZE AND ITS BIMODAL DISTRIBUTION FOR HIGHLY THERMAL-CONDUCTIVE EPOXY COMPOSITES
www.iccm-central.org/Proceedings/ICCM18proceedings/data/3.%20Poster%20Presentation/Aug22(Monday)/P1-1~20%20Applications%20of%20Composites/P1-8-IK0296.pdf

[lawry]

How thick would it have to be to avoid cracking?
The materials are quite expensive. Corundum is classified as semi precious stones. I also bought silicon carbide which was also expensive.
Any cheaper alternatives?

[Deleted]

Corundum is just the densest and hardest form of aluminum oxide.
Fused aluminum oxide is created in large amounts.
Natural corundum has a lower conductivity due to impurities.
Other forms of aluminum oxide have lower thermal conductivity,
but still relatively high.

Anything crystalline with high hardnes and high purity has a high thermal conductivity.
The purer the harder the higher.
Exception Zirconia: With a low specific heat the hardness is not enough for high conductivity.

Creating something in high purity is expensive.
Extremely hard things have also extremely high melting points,
which makes processing expensive.

[lawry]

I am getting a bag of aluminum oxide today. I have silicon carbide as well. I will cast a 25mm puck. Then do the reverse side tests.