Applied Radiation

X-Ray Powder Diffraction (D8 Advance)

D8 Advance instrument at the X-ray diffraction facility

Instrument description

Necsa’s powder diffraction instrument is a commercial Bruker D8 Advance diffractometer that is used for the investigation of crystalline materials. It has a vertical theta-theta goniometer geometry in which the sample remains horizontal. Collection of the diffracted data is done using a 1-D silicon technology-based Lynx Eye detector. In routine applications such as phase identification analysis of powdered samples using an automated multi-position sample stage, that enables continuous sample rotation during analysis, is the standard configuration. For non-routine analysis, involving large samples, or for spatial mapping, an XYZ stage is available. For very small samples, a capillary stage can be used.

The primary beam optics is conditioned by a Goebel mirror that enables grazing incidence angle analysis of thin films or oxide layers. It in addition negates contributions from irregular surfaces in solid samples. The X-ray wavelength can be matched to the material being investigated by employing different X-ray tubes that include Cu, Co and Cr. 

The instrument is housed in a radiologically controlled building, where in conjunction with special hermitically sealed sample holders, NORM and uranium containing samples can be investigated in compliance to radiological safety assessments and monitoring. 

Technical

X-ray Tubes

Cu (1.54 Å), Co (1.79 Å), Cr (2.29 Å)

Primary beam conditioning

Göbel mirror

Beam sizes

0.1 x 15 mm2; 1 mm collimator

Sample stage

7 position Flip-stick

Large component XYZ stage

Capillary stage

Pseudo-SAXS stage

Hermitically sealed stages

Sample setup

Laser system

Detector

LynxEye

Software

Latest ICDD PDF-4+ database

Topas

NanoFit (Pseudo SAXS)

Data Collection:

Data collection is performed via XRD commander application on a dedicated instrument control computer.

Data reduction and analysis:

We provide qualitative and quantitative data analyses depending on the client’s needs, as discussed below.

Qualitative data analyses:

Once the raw data is collected, it is uploaded on a dedicated data reduction and analysis computer. Data treatment for the Search/Match procedure comprises subtracting the background contribution and stripping the K-α2 X-ray beam contamination from the as-measured diffraction patterns. Qualitative identification of the crystallographic chemical phases is carried out via the Search/Match technique where the measured diffraction peaks (intensities and peak positions) are matched against the ICDD PDF-4+ database (with over 400 000 entries) using the Sieve+ software.

Quantitative data analyses:

Once the peaks have been identified with stick patterns, quantitative phase content analysis is performed using TOPAS software that is based on the Rietveld Refinement method.

Project Examples

(a) Qualitative phase identification analysis
(b) Quantitative chemical phase analysis

XRD phase analysis of incubated plasma sprayed coatings: (a) Qualitative phase identification analysis; (b) Quantitative chemical phase analysis.  

Extract of research results that have benefitted from utilisation of the instrument:

  1. M. Vilakazi, O. S. Monnahela, J. B. Wagener, P.A.B. Carstens, TP Ntsoane, A thermogravimetric study of the fluorination of zirconium and hafnium oxides with anhydrous hydrogen fluoride gas. Journal of Fluorine Chemistry, Vol. 141, 2012, 64-68
  2. S. Monnahela, B.M. Vilakazi, J.B. Wagener, A. Roodt, P.A.B. Carstens, W.L. Retief, A thermogravimetric study of the fluorination of zirconium and hafnium oxides with fluorine gas, Journal of Fluorine Chemistry, Volume 135, March 2012, 246-249

L.D.Kock, M.D.S.Lekgoathi, P.L.Crouse, B.M.Vilakazi, Solid state vibrational spectroscopy of anhydrous lithium hexafluorophosphate (LiPF6), Journal of Molecular Structure, Vol 1026, 2012, 145-149

Kramers, J.D., Andreoli, M.A.G., Atanasova, M., Belyanin, G.A., Block, D., Franklyn, C., Harris, C., Lekgoathi, M., Montross, C.S., Ntsoane, T., Pischedda, V., Segonyane,,P., Viljoen, K.S., Westraadt, J.E, .Unique chemistry of a diamond-bearing pebble from the Libyan Desert Glass strewnfield, SW Egypt: Evidence for a shocked comet fragment., 2013. Earth and Planetary Science Letters, 382, 21-31.

  1. T. Thabethe, E. G. Njoroge, T. T. Hlatshwayo, T. P. Ntsoane, J. B. Malherbe, Surface and interface structural analysis of W deposited on 6H–SiC substrates annealed in argon., Royal Society of Chemistry Adv.,2017,7,,2, 7

S. Biira, P.L. Crouse, H. Bissett, T.T. Hlatshwayo, E.G. Njoroge, J.T. Nel, T.P. Ntsoane, J.B. Malherbe,The role of ZrCl4 partial pressure on the growth characteristics of chemical vapour deposited ZrC layers. Ceramics International, Vol 43, Issue 17,  2017, 15133-15140

S. Biira, B.A.B. Alawad, H. Bissett, J.T. Nel, T.P. Ntsoane, T.T. Hlatshwayo, P.L. Crouse, J.B. Malherbe, Influence of the substrate gas-inlet gap on the growth rate, morphology and microstructure of zirconium carbide films grown by chemical vapour deposition. Ceramics International, Vol 43, Iss 1, Part B, 2017, 1354-1361

N  Manyala, N M Ndiaye, B D Ngom,, N F Sylla, T M Masikhwa, MJ Madito, DY Momodu, T Ntsoane, Three dimensional vanadium pentoxide/graphene foam composite as positive electrode for high performance asymmetric electrochemical supercapacitor. Journal of Colloid and Interface Science, Vol 532,  2018,  395-406

  1. H. Rondahl, F. Pointurier, L. Ahlinder, H. Ramebäck, O. Marie, B. Ravat, F. Delaunay, E. Young, N. Blagojevic, J. R. Hester, G. Thorogood, A. N. Nelwamondo, T. P. Ntsoane, S. K. Roberts, K. S. Holliday, Comparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise, Journal of Radioanalytical and Nuclear Chemistry, 2018, Vol 315, Iss 2, 395–408.

Instrument scientist(s):

  • Mr. Tjatji Tjebane
  • MSc Physics   
  • Email:   tjatji.tjebane@necsa.co.za
  • Tel:      +27 (0) 12 305 5852/5427
  • Dr. Tshepo Ntsoane    
  • PhD Physics   
  • Email: tshepo.ntsoane@necsa.co.za
  • Tel: +27 (0) 12 305 5400/5427

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