Epsilon-iron allotrope. 3

[Greenleader]

Simple question, when and where does epsilon-iron, (hexagonal, close packed), exist. That is on the surface of the earth? Thanks.

 

[metengr]

Greenleader;
Any place on Earth where the temperature is 25 deg C and the pressure is greater than 13 GPa.

Source;
ASM Metals handbook, Desk Edition, pg 92

 

[TVP]

I looked through the various Fe phase diagrams in ASM HANDBOOK Volume 3, and found only a few systems where epsilon is a stable phase: Fe-Ir, Fe-N, Fe-Nb, Fe-Sb, Fe-Te. Of these, only the Fe-N system is likely to exist in any substantive form, and that occurs when iron-based parts are heat treated in a nitrogen-based atmosphere (called nitriding). Epsilon is stable when the N content is ~ 4-11 % by mass.

 

[metengr]

http://www.crct.polymtl.ca/fact/documentation/SGTE/SGTE_Figs.htm

 

[Greenleader]

Is epsilon iron magnetic?

 

[metengr]

http://www.ncbi.nlm.nih.gov/pubmed/15697906

 

[metengr]

Here is more light reading on the subject

http://www.iop.org/EJ/abstract/0305-4608/4/11/020/

 

[Greenleader]

Thank you!
Do you think epsilon iron, (not carbides), can be ordered by chemistry @ normal pressures?

 

[unclesyd]

Checkout the technical literature at this site. Look at the paper "Liquid Ferritic Nitrocarburizing" to see how it can be formed and retained.

http://www.nitromet.com/