negative CTE ceramic material

[etrusco]

Hi everybody!
I am new here and hope to find an answer to my question.
Wishing to improve a flame-proof ceramic compound I search a material exibiting a negative CTE in the range 20-700°c.
May be Beta Eucryptite could have this feature but I don't find a thermal diagram of it and a possible supplier.
Is there anyone that could help me?
Thank you.

 

[unclesyd]

I would give Schott Glass a call about their material Resistan which may fill your requirements. There also might be something else in their pipeline.

http://www.us.schott.com/hometech/english/products/resistan/technical/thermal.html

Probably the best material would be ZrW2O8(Zirconium Tungstenate} the only problem is it's still a laboratory curosity.

 

[Ceramicguy]

Why do you need a negative CTE? Are you trying to offset a positive CTE in a constituent of your material--basically tailor an expansion coefficient to match the substrate material? A couple of options for low CTE materials:

Fused silica--slightly negative CTE up to about 200C

Zerodur--Schott Glasswerke product

ULE--Corning product

Zirconium Phosphate--SMAHT Ceramics product

beta spodumene--Morgan Ceramics GBC division product (Zeramic)

Bruce

http://www.accuratus.com

 

[PKerEng]

I suggest to give a consideration to a very industrially mature cordierite ceramics. It proved itself as a very inexpensive thermal shock resistant ceramics in both porous and sealed (self-glazed) variations. Obviously, it can not compete with quartz glass but it shows low positive CTE and its porous version is very popular for heater core applications. Need shapes, contact more traditional technical ceramic manufacturers (try DuCo ceramics).

Slawomir

http://www.pkerengineering.com