X-ray powder diffraction studies of mechanically milled cobalt

W. S. Yeo, Z. Nuramirah, H. S.C. Metselaar, T. H. Ong

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The allotropic phase transformation of cobalt powder prepared by high-energy ball milling was investigated as a function of milling time. Measurement of crystallite size and microstrain in the powder systems milled for different times were conducted by X-ray diffractometry. The X-ray diffraction (XRD) peaks were analyzed using the Pearson VII profile function in conjunction with Rietveld method. X-ray diffraction line broadening revealed that allotropic transformation between face-centred-cubic phase (fcc) and hexagonal close-packed phase (hcp) in cobalt is grain size dependent and also on the accumulation of structure defects. The results showed that the phase formation of cobalt depends on the mill intensity that influences of both the grain size and the accumulation of structure defects. However, this theory alone is not adequate to explain the effects in this work. It was found that the total surface energy (∧) theory satisfactorily explains the phase transformation behavior of cobalt. The smaller value of surface energy (∧) of the fcc crystal than the hcp phase when size decreases may alter the qualitative aspects of the phase formation.

Original languageEnglish
Title of host publicationAdvanced Materials Engineering and Technology
Pages913-917
Number of pages5
DOIs
Publication statusPublished - 24 Jan 2013
Event2012 International Conference on Advanced Materials Engineering and Technology, ICAMET 2012 - Penang, Malaysia
Duration: 28 Nov 201230 Nov 2012

Publication series

NameAdvanced Materials Research
Volume626
ISSN (Print)1022-6680

Other

Other2012 International Conference on Advanced Materials Engineering and Technology, ICAMET 2012
CountryMalaysia
CityPenang
Period28/11/1230/11/12

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All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Yeo, W. S., Nuramirah, Z., Metselaar, H. S. C., & Ong, T. H. (2013). X-ray powder diffraction studies of mechanically milled cobalt. In Advanced Materials Engineering and Technology (pp. 913-917). (Advanced Materials Research; Vol. 626). https://doi.org/10.4028/www.scientific.net/AMR.626.913