Hi Antonio
I have tried the position of C atom, and i have supposed that could be in
8a,whic is an intersticial position, as Frank says, but you have to
specify the site occupation, which is related to carbon content.
Best wishes.
Miguel Hesiquio
On Fri, October 31, 2008 8:05 am, Frank Girgsdies wrote:
> Dear Antonio,
>
>
> as far as I know, austenite is just a solid solution of a few mole-% of
> carbon in gamma-iron. Thus, you essentially need the structure of
> gamma-Fe, which is very simple, as it is an fcc metal (space group Fm-3m, a
> = 3.6468 A, just one
> Fe atom located on 0,0,0).
> I found one ICSD entry for austenite.
> However, the dissolved carbon is placed sharing
> the Fe site in this structure, which I doubt makes sense from the chemical
> point of view. I would bet the carbon atoms are actually located
> on interstitial sites instead. Anyway, as we are talking about a few MOLE-%
> of carbon here, and carbon is much lighter than iron, I think neglecting
> the carbon will not make much of a difference (both for the accuracy of the
> calculated relative intensities and the quantification in wt-%. Thus, I
> would just use gamma-Fe as a replacement for austenite here.
>
> Cheers,
> Frank
>
>
> ------------------------------------------
> Frank Girgsdies
> Department of Inorganic Chemistry
> Fritz Haber Institute (Max Planck Society)
> ------------------------------------------
>
>
> antonio josé wrote:
>> Dear All.
>>
>>
>>
>>
>> I trying analyze phases in a steel sample using X-Ray technique. The
>> analysis of X-Ray pattern shows that the main phases are ferrite and
>> austenite. The next step would be quantify these phases by Rietveld
>> method using TOPAS 3.0. I am looking for cif files for austenite and I
>> didnt find it in WEB free database or in ICSD database.
>>
>> Do anyone has this cif file or could tell me where I can find?
>>
>>
>>
>>
>> Thanks a lot,
>>
>>
>> Antonio José
>>
>>
>> [EMAIL PROTECTED]
>>
>
>
