Fe3C (Cementite)

[Probeman]

Does anybody know where one might be able to obtain a nice clean (synthetic) Fe3C (Cementite) standard?

I have other materials to trade such as SiO2 characterized by ICP-MS if that is interesting.

[Anette von der Handt]

Hi John,

I have cementite that was synthesized here in our high pressure lab. We use it as a standard for our carbon analyses. It is not perfectly homogeneous (a common problem with cementite to my understanding) but perfectly serviceable. I'll send you a piece (or how much do you need?).

Otherwise, here is a also a reference to a certified cementite standard:
Stuart Saunders;
, Peter Karduck, and Willem G. Sloof (2004): Certified Reference Materials for Micro-Analysis
of Carbon and Nitrogen. Microchim. Acta 145, 209

[JohnF]

Many years ago a postdoc from Chemistry? Material Science? had some powders he'd synthesized and wanted to do epma on them and I gave him to standard gospel that we can't do epma on powders...but he was clever and knew more than I did... the trick is to have a small (cm diameter I think he used) press with the bottom surface with a mirror polish on it. Given that the grains were small enough, it worked. The reflected light image, while not perfect, showed a smooth, reflective surface, close enough for what he needed. So if the cementite grains are small enough, you might be able to "make do". (I don't now recall what materials the postdoc was mounting and they mave have been soft or ductile enough to flow; not sure what material properties of cementite are....)

[Probeman]

Owen, thank-you for the Fe3C powder. Do you have any idea when it was synthesized? I have heard that over extended periods of time, cementite will slowly break down even at room temperatures, as this wiki page seems to suggest:

http://en.wikipedia.org/wiki/Cementite