My numbers are from experence , even a thin liner can knock off the the top several hundred degrees , but as you go lower it gets harder and harder , like 2500-2000 is low hanging fruit , and 500- 200 is much harder to achieve . any theories ?

ladle liners are usually oxides  , remember fluorine will use oxides as Fuel  .  

As to the different coefficients of expansion High conductivity is the way to fight that  , carbon migration there are solid rocket nozzles (castor booster on the delta I think ) course that is very short duration but the shuttle boosters might accumulate some time maybe there was a study ?

1 minute ago, robertsolo said:

, remember fluorine will use oxides as Fuel  .  

Yep.

But you didn't say you were using fluorine; you said AlF3.

 

But with two material solution the temperature of the metal is lower , I thought we were talking about two material solutions now , in any case cold working the material is going to achieve necessary strength (at 1700 F ) I can tell you that with even testing it .

6 minutes ago, robertsolo said:

High conductivity is the way to fight that

How?

 

I would really love to answer that question , but I think you are figuring it out already , I feel like those germans no mater how few clues you drop , someone will figure it out .  I am jeopardizing my job at this point  , sorry but I must stop .