NCNR SETS THE STANDARD FOR QUANTITATIVE PHASE ANALYSIS.Personnel from the NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. Center for Neutron Research (NCNR NCNR NIST Center for Neutron Research NCNR Non-Cancelable, Non-Returnable NCNR National Center for Nursing Research (NIH) NCNR Nearest Common Node Rerouting (ATM) NCNR National Center for Neutron Research ) recently participated in an international round-robin on the use of diffraction techniques for the quantification of phase abundance in multiphase Mul´ti`phase a. 1. (Elec.) Having many phases; Adj. 1. multiphase - of an electrical system that uses or generates two or more alternating voltages of the same frequency but differing in phase angle mixtures. This type of analysis is essential for the characterization, development, and performance of many industrial materials, such as thermal barrier coatings employed in aircraft engines. The round-robin included participants from x-ray, synchrotron synchrotron: see particle accelerator. synchrotron Cyclic particle accelerator in which the particle is confined to its orbit by a magnetic field. The strength of the magnetic field increases as the particle's momentum increases. , and neutron facilities worldwide, and was sponsored by the Commission on Powder Diffraction of the International Union of Crystallography The International Union of Crystallography (IUCr) is a member of the International Council for Science (ICSU) and exists to serve the world community of crystallographers. See also X-ray crystallography Crystallography External links Results to date show a wide variation in performance for various methods. For example, in one standard mixture containing 34.2 % zinc oxide, results obtained using laboratory x-ray sources ranged from 25 % to 42 %, results from synchrotron sources ranged from 29 % to 35 %, and those from neutron sources ranged from 32 % to 35 %. NCNR analysis gave 34.4 %. For all 10 mixtures analyzed, the NCNR results agreed within statistical limits with the nominal compositions and, overall, gave the best results in the study. The results of this study again emphasize the importance of neutron methods in providing accurate data on phase composition in industrial materials. |
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