M-Doped Al^sub 2^TiO^sub 5^ (M=Cr, Mn, Co) Solid Solutions and their Use as Ceramic Pigments

• Published in: Journal of the American Ceramic Society Vol. 92; no. 9; p. 1972
• Main Authors: Dondi, Michele, Lyubenova, Teodora Stoyanova, Carda, Juan B, Ocaña, Manuel
• Format: Journal Article
• Language: English
• Published: Columbus Wiley Subscription Services, Inc 01.09.2009
• Subjects: Aerosols; Ceramics; Microstructure; Pigments; Scanning electron microscopy; Spectrum analysis
• ISSN: 0002-7820

New ceramic pigments based on the tialite (...) structure, doped with Co (pink), Cr (green), or Mn (brown), were prepared through the pyrolysis of aerosols followed by calcination of the obtained powders at 1400...C. The expected decomposition of ... into a mixture of ... and ... on refiring was inhibited by Cr-doping and also by co-doping with Mg the Mn- or Co-doped samples. Microstructure and phase evolution during pigment preparation were monitored by scanning electron microscopy and XRPD. Unit cell parameters of tialite were determined by Rietveld refinement of the X-ray diffraction patterns, revealing in all cases the formation of solid solutions where the solubility of dopants in the ... lattice followed the trend Co<Mn<Cr. The valence state and possible location of dopants in the tialite lattice were investigated by X-ray photoelectron spectra and diffuse reflectance spectroscopies, which suggested the presence of ... ions in a large interstitial site of the tialite lattice with a distorted octahedral geometry, and of ... and ... ions in the ... octahedral sites of the tialite lattice in the former case, and in both ... and ... octahedral sites in the latter. Testing the ceramic glazes assessed the technological behavior of pigments, which found that the color stability was reasonably good for the Mn-doped tialite and the Cr-doped pigment, although the latter suffered a small loss of green hue. The Co-doped pigment was found to be not stable in glazes, undergoing a cobalt-leaching effect. (ProQuest: ... denotes formulae/symbols omitted.)