Thanks Jim for the useful info. I was not aware of this kind of silicon standard until now. But can't be polycrystallinity of Silicon a drawback to use it as standard? Or is there a way to "purify" a single phase suitable to use as standard? I have always found more useful having LaB6 or corundum (whenever LaB6 is expensive to find) to use it as standard to compare instrumental peak broadening. In some of the Rietveld software I use or I know, also yttria is used to determine peak broadening. Which criteria do you use when choosing a suitable pxrd standard to compare your unknown? Why?
Thanks for the enlightening discussion. Fabrizio Guzzetta Ph.D. student, Dept. Quimica Inorganica y Organica, UJI Castellon de la Plana Spain 2015-07-13 19:56 GMT+02:00 Cline, James Dr. <james.cl...@nist.gov>: > Lindsay, > > > > I’ve seen pressed discs of silicon powder that were supplied with older > Philips diffractometers, and I understand that PANalytical will presently > supply them with their new machines. NIST offers no such standard of > silicon in a disc format. But I can suggest that you consider SRM 640e > which is supplied as powder. One can mount a specimen of it carefully to > obtain high density and a flat specimen surface, and then infiltrate the > powder bed with silicone based liquid resin such as Vacseal. See: > > > > http://www.2spi.com/catalog/vac/vacleak.shtml > > > > The surface of the compact will darken to a uniform color when the > infiltration is complete. This will result in a stable compact with the > diffraction properties of SRM 640e. > > > > Regards, > > > > Jim > > > > > > James P. Cline > Materials Measurement Science Division > National Institute of Standards and Technology > 100 Bureau Dr. stop 8520 [ B113 / Bldg 217 ] > Gaithersburg, MD 20899-8523 USA > jcl...@nist.gov > (301) 975 5793 > FAX (301) 975 5334 > > > > *From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] *On > Behalf Of *Young, Lindsay Kay > *Sent:* Friday, July 10, 2015 1:28 PM > *To:* rietveld_l@ill.fr > *Subject:* Obtaining a silicon standard wafer > > > > Hello Rietvelders - > > > > This is not exactly a data question, but I am sure someone here can help. > I am looking into purchasing a silicon powder standard wafer for PXRD > instrument alignment. However, I am not sure where to get one or how much I > might expect one to cost. My questions to all of you are: > > > > - Do you know where I could purchase this type of standard? > > - How much would you expect to pay for one? > > - I have been told Gem Dugout makes these, but they may not be around any > more. Does anyone know what happened to them? > > > > Thank you very much for your help, and I hope you all have a great > weekend! > > > > - Lindsay Young > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
