Phase transformations in nickel sulphide: Microstructures and mechanisms

Oussama Yousfi, Patricia Donnadieu, Yves Bréchet, Florence Robaut, Frédéric Charlot, Andreas Kasper, Francis Serruys

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15 Citations (Scopus)


Nickel sulphide inclusions are known to be responsible for delayed fracture in tempered glasses due to phase transformation within the inclusion. Microstructural identification of the phase transformation mechanisms in the Ni-S system close to the NiS composition were carried out on a series of partially transformed states. Observations allow to investigate the morphological evolution during transformation, the phase orientation relationships and the first stages of the transformation were investigated by optical microscopy, electron backscatter diffraction, and scanning and transmission electron microscopy. The transformation mechanisms change significantly with the change in sulphur content of the α-NiS phase. Massive transformation is observed for near-stoichiometric composition. For overstoichiometric composition, the transformation is controlled by a long-range diffusion mechanism. The influence of stoichiometry and impurities (Fe) on the microstructural evolution and transformation mechanisms has also been studied.

Original languageEnglish
Pages (from-to)3367-3380
Number of pages14
JournalActa Materialia
Issue number9
Publication statusPublished - May 2010
Externally publishedYes


  • Diffusive transformation
  • Massive transformation
  • Microstructure
  • Nickel sulphides
  • Phase transformation

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