Sciencemadness Discussion Board

Phosphate bonded cements.

Tacho - 2-3-2004 at 06:35

I use dentist´s casting investment to make refractory bits and pieces. You use it as plaster of paris (gypsum), but it resists very high temperatures. It is called a “phosphate bonded” investment. I PRESUME (as in: I´m not sure) it has retains no water of hydratation after it´s hard and heated, opposite to plaster of paris or portland cement.

Could anybody confirm this?

I ask because I presume that, holding no water of hydratation, it would be a good insulator for high voltages at high temperatures.

Just to make sure you know what I am talking about, I add some links:

http://r-curtis.umds.ac.uk/bds3a/Investment%20materials%201....

http://www.spofadental.com/ostatni-gb.htm

http://www.servo-dental.de/enpages/labline/guss.html

http://www.rutenium.com.br/inglesteste/pdf/choquetermicoIngl...

axehandle - 4-3-2004 at 06:56

Check out my V2O5 thread in the Reagents section. I've acquired 500g of the stuff (for FREE!) and am going to experiment with it.

Edit: It's called "GC Fujivest Super" and is made in Belgium.


[Edited on 2004-3-4 by axehandle]

Resistance to SO2 / SO3

axehandle - 4-3-2004 at 08:56

I wonder if the phosphate bonded cement is resistant to SO2 and SO3. If it were, I could embed the heating wire on the <b>inside</b> wall of the catalyst tube, and then cover it with a thin layer of the cement.

Anyone who knows?