The mechanism for the colour change of iron chromium black pigments in glazes through transmission electron microscopy techniques


YURDAKUL H., TURAN S., ÖZEL E.

DYES AND PIGMENTS, vol.91, no.2, pp.126-133, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 91 Issue: 2
  • Publication Date: 2011
  • Doi Number: 10.1016/j.dyepig.2011.03.014
  • Journal Name: DYES AND PIGMENTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.126-133
  • Keywords: Fe-Cr black pigment, Glaze, Transmission electron microscopy (TEM), Electron energy loss spectroscopy (EELS), Energy dispersive X-ray spectroscopy (EDXS), Focused ion beam (FIB), CERAMIC PIGMENTS, OXIDATION-STATES, THIN-FILMS, FE, SYSTEMS
  • Anadolu University Affiliated: Yes

Abstract

Black iron chromium (Fe-Cr) bearing oxide pigments are generally utilised as effective colourants in a wide variety of applications. However, in the case of their use within ZnO-containing glazes, they yield an undesirable brown colour instead of expected black colour. In order to understand the colour change in this system, we report the use of focused ion beam (FIB) sample preparation technique followed by the use of analytical transmission electron microscopy (TEM) characterisation techniques. According to the results, the formation of a reaction layer between the pigment and glaze was identified with an average composition of Zn(0.48)Fe(0.79)Cr(1.32)O(4). Additionally, the valance of Fe was determined as 3+ in the pigment grain, whereas 2+ in the reaction layer and the glaze, respectively. Therefore, it was concluded that the colour change is occurring as result of the valence variation of Fe, the formation of Zn(0.48)Fe(0.79)Cr(1.32)O(4) compound and the outward diffusion of Fe into the glaze. (C) 2011 Elsevier Ltd. All rights reserved.