Stephen, The peak profile gives information about the crystallite or coherent diffracting domain size along with microstrain. You cannot not get a grain size unless the crystallite size can be related to the grain size from knowledge of the microstructure. The crystallite size can be estimated using the Scherrer equation assuming no microstrains and a spherical shape. The equation is the thickness or size = (0.9 X lambda)/(breadth(radians) X sin(theata)), that is if I remember correctly since I am currently in the hospital. I hope this helps, a rather simple calculation that provides a good estimate. I should note there are correction schemes of gaussian and lorentzian (I normally use a geometric mean of the two) that is important when the breadth is only a couple of hundreds or less (please see B.D. Cullity Elements of X-Ray Diffraction in my opinion one of the best XRD references). Also the values change with angle so I typically have found averaging the values of the 5 lowest angl! e peaks is close to the Warren-Averbach results.
Cheers, Ed ----- Original Message ----- From: [EMAIL PROTECTED] To: "Rietveld L" <Rietveld_L@ill.fr> Sent: Wednesday, November 12, 2008 5:42:37 AM GMT -05:00 US/Canada Eastern Subject: Suggestion about software(s) for size profile-broadening calculation Dear all experts in XRD, As stated in the header, does anyone know if there is some software(s) available for estimation of average crystal grain size using the peak breath of XRD data? I just want to know some rough values so as to compare my samples prepared at different conditions. Many thanks for your kind helps. Great appreciate. stephen -- Engineer/Scientist Michigan Technological University Dept of Materials Science and Engineering Phone:(906) 369-2041 Fax: (906) 487-2934 -- Engineer/Scientist Michigan Technological University Dept of Materials Science and Engineering Phone:(906) 369-2041 Fax: (906) 487-2934
