F. Garrett, D.J. Cookson, G. J. Foran, T.M. Sabine, B. J. Kennedy and S. W.. Wilkins, âPowder Diffraction Using Imaging Plates at the Australian National.
Copyright (C) JCPDS International Centre for Diffraction Data 1999
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DENVER X-RAY CONFERENCE ( 1997)
Characterization of Standard Radiation Diffraction Data
Reference
Materials
Using
Synchrotron
Brian O’Connor, Arie van Riessen and Graeme Burton Materials Research Group, Department of Applied Physics Cur-tin University of Technology GPO Box U1987, Perth, WA, Australia 6845 and David Cookson and Richard Garrett Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW, Australia 2234
Abstract The value of using synchrotron radiation diffraction (SRD) for characterising standard reference materials (SRMs), as a supplement to laboratory x-ray powder diffraction (XRD) analysis, has been demonstrated with the National Institute of Standards and Technology LaB6 material NIST SRM 660. Measurements were performed under in vacua conditions with the high-resolution BIGDIFF DebyeScherrer instrument (radius = 573 mm) at the Photon Factory, Tsukuba, Japan using a wavelength of 1.5378 A and a capillary-mounted specimen (diameter = 0.5 mm). A diffraction pattern recorded with imaging plates in 15 minutes provided pattern resolution and trace-phase(< 1 Oh) detectability in SRM 660 which are clearly superior to results for Bragg-Brentano laboratory XRD data collected in 1 hour. Search/match analysis of the SRD data readily revealed the presence of three impurity phases - aAl203; the binary metal oxide La203*MO [M = metal]; and l&alumina material of the type 1 lAl203*LazO:+*MO which were probably produced during the preparation of the SRM. While there are clear indications of some contaminant peak features in the corresponding XRD pattern, these could not be used to unequivocally identify the three contaminant phases. Rietveld phase composition analysis with the SRD data readily provided values for these trace phases.
Introduction The present study was undertaken to evaluate the potential of BIGDIFF, a new synchrotron radiation (SR) diffraction (SRD) instrument, for characterising standard reference materials (SRMs). BIGDIFF is a multi-purpose SR materials analysis system operating at the Australian National Beamline Facility (ANBF) on Beamline 20B at the Photon Factory, Tsukuba, Japan [l-3]. One of the operating configurations of the instrument involves Debye-Scherrer optics, with a diffractometer radius of 573 mm,
Copyright (C) JCPDS International Centre for Diffraction Data 1999
corresponding to a 28 scaling factor of lo/cm along the instrument circumference; capillary-mounted specimens; and recording of the difiaction pattern with imaging plates (II%). BIGDIFF can rapidly provide (99% pure.” It appearsthat the impurities are due to the sheddingof material by the milling media and mill container, and subsequentmechanicalalloying interactions.
17000 15000
A: CFAJO, [43-14841 B: [La,Ca]20,.Coz0, [36-13911
go00
T: 2MgO. 11A~0,.La20, 7000 i,,,,, 0
I‘ 5
,,,,,,,,,,,,,,,,,,,,,,,,,,,, 10
15
[26-8731’
# ,,,, 20
25
30
35
#,,, 40
300
200
100
0
Figure 1. Low-angle portions of the diffraction patterns for the SRM 660 specimen:(a - top) SRD plot for h = 1.5378 A; and (b - below) XRD plot for h = 1.5418 A, CuKcz. The line assignmentsshown for the SRD pattern were identified by search/match analysis taking into account the FWHM-versus-28 plots in
Figure 2 - symbolsA, B and T refer to the phasesa-Alz03, La203*M0 [M = metal]; and 11Alz03*La203~M0, respectively. Symbol W in the XRD diagram refers to features caused by tungsten contamination of the x-ray tube anode.
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Copyright (C) JCPDS-International Centre for Diffraction Data 1999
541
2MgO.l lAl,O,. /
0
10
20
30
50
40
60
70
80
90
23 ("I
Figure 2. Plot of FWHM-versus-28for the near-background SRD Bragg peaks. The largefilled circlesrepresentlinesnot assignedby search/match analysis.
Table2. Search/MatchAnalysisTrace-Phase Resultsfor SRDPattern Best-matched Phases CCAl~O~ (La,Ca)zO&o203[cubic] 2MgO.l 1Al,03.La20x
ICDD - JCPDS# 43-1484 36-1391 26-873
The Rietveld phase composition results are given in Table 3. The crystal structure models employed in the calculationsfor the four phaseswere taken from the ICSD data base - the structures in references 9 -12 for La&, a-Al~03, (La,Ca)203.Co203 and 2Mg0.11AlzOpLa20,, respectively. It should be noted in considering these results that the wt % values are relative concentrations and that there may be at least one other phasepresent, albeit with wt % less than 1 %. The phasecomposition for LaBs agreesclosely with the value 99 % specified on the SRM 660 Certificate of Analysis. The superior sensitivity of the BIGDIFF SRD analysisis evident from the concentrations of the trace phaseswhich have been quantified at levels below 1 %.
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Copyright (C) JCPDS-International Centre for Diffraction Data 1999
Table3. RietveldPhaseCompositionAnalysisResults Phase
ICSD* Reference
wt % (rel)
La6
63600
98.9 (0.2)**
CX-Al*O~
73725
0.43 (0.30)
La203.Co203[cubic]
28921
0.38 (0.05)
2Mg0.11A1203.LaZ03
65360
0.25 (0.22)
* Inorganic Crystal Structure Database(Gmelin Institut) * * Values in parenthesesrepresentthe estimatedstandard deviationsin terms of the least significant figures to the left. Conclusion The results underline the attraction of employing SRD for characterizing SRMs. The technique is clearly superior to Bragg-Brentano XRD in terms of the detection of trace phasesand the assessmentof line profile character, e.g. for residual strain analysis. SRD data collected with the BIGDIFF Debye-Scherrerinstrument in only 15 minutes are clearly superior to Bragg-Brentano laboratory XRD data measured under typical data measurementconditions (approximately 1 hour acquisition time). The ready detectability of three impurity phasesin the NIST SRM 660 LaB6 specimen, present at levels below 1 % concentration,in contrast with the XRD data set for which these phasescould not be unequivocally identified, has shown that the detection limits for trace phases(cl%) in SRM analysiswill be substantially superior with BIGDIFF SRD data. The result is clearly due to the superior dynamic range and angular resolution of the SRD instrument. Acknowledgement The authors wish to acknowledgea grant in 1994 from the Australian National Beamline Facility which is funded by a consortium comprising the Australian Research Council: the Department of Industry, Technology and Regional Development; the Australian Nuclear Science and Technology Organisation; the Australian National University and the University of New South Wales. We are also grateful to our colleague, D Y Li, for collecting the XRD data.
Copyright (C) JCPDS-International Centre for Diffraction Data 1999
References lR.F. Garrett, D.J. Cookson, G.J. Foran, T.M. Sabine, B. J. Kennedy and S.W. Wilkins, “Powder Diffraction Using Imaging Plates at the Australian National Beamline Facility at the Photon Factory,” Rev. Sci. Inst. 66, 1351-1353 (1995). 2T.M. Sabine, B. J. Kennedy, R.F. Garrett, G.J. Foran and D.J. Cookson, “The Performance of the Australian Powder Diffi-actometer at the Photon Factory, Japan,” J Appl. Crystallogr. 28, 513-517 (1995). 3B.H. O’Connor, A. van Riessen, J. Carter, G.R. Burton, R.F. Garrett and D. J. Cookson, “Characterization of Ceramic Materials with the BIGDIFF Synchrotron Radiation Debye-Scherrer Diffractometer,” J. Amer. Ceramic Sot. 80, 1373-1381 (1997). 4B.A. Latella and B.H. O’Connor, “Detection of Minor Crystalline Phases in Alumina Ceramics Using Synchrotron Radiation Diffkaction Data,” J. Amer. Ceramic sot. 80, 294 l-2944 (1997). 5National Institute of Standards& Technology, Certificate of Analysis, Standard ReferenceMaterial 660. Instrument Line Position and ProJie Shape Standard for Xray Powder Diffraction. Gaithersberg,Md. (1989). 6R.D. Deslattes, J.P. Cline, J.-L. Staudenmann,E.G. Kessler, Jr., L.T. Hudson and A. Hennins, “Status of the Development of SRM 64Oc,” 46th Annual Denver X-ray Conference(1997). Abstracts Volume, ~70. ‘R. J. Hill, C. J. Howard and B.A. Hunter, “A Computer Program for Rietveld Analysis of Fixed Wavelength x-ray and Neutron Powder Diffraction Patterns,” Australian Atomic Energy Commission (now ANSTO). Rept. No. M112, Lucas Heights ResearchLaboratories, New South Wales,Australia, 1995. sD. E. Cox, B. H. Toby and M. M. Eddy, “Acquisition of Powder Diffraction Data with Synchrotron Radiation,” Aust. J. Phys. 41, 117-131 (1988). gM.M. Korsukova, V.N. Gurin, T. Lundstroem and L-E. Tergenius “The Structure of High-temperature Solution-grown LaBa: A Single-crystalDifiactometry Study,” J Less-CommonMetals 117, 73-81 (1986). 1eE.N. Maslen, V.A. Streltsov, N.R. Streltsova, N. Ishizawa and Y. Satow, ” Synchrotron X-ray Study of the Electron Density in a-Al203,” Acta Crystallographica B49, 973-980 (1993). 11A. Wold and R. Ward, “Perovskite-Type Oxides of Cobalt, Chromium and Vanadium with Some Rare Earth Elements,” J. Am. Chem. Sot. 76, 1029-1030 (1954). l2R. Brandt and H. Mueller-Buschbaum, “Ein Beitrag zur Kristallchemie der Lanthanoidmagnetoplumbite,” Zeit. fuer Anorg. und Allgemeine Chemie. 510, 163168 (1984).
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