Co-doped willemite ceramic pigments: Technological behaviour, crystal structure and optical properties

Co-Doped Hardystonite, Ca2(Zn,Co)Si2O7, a New Blue Ceramic Pigment

“…2). 24,37 The micrograph of hardystonite sample H30 reveals a heterogeneous distribution of the particle size, ranging from 5 mm to the sub micrometer range, mostly with botryoidal grains and rounded lamellae (Fig. In fact, the strong hybridization of sp 3 orbitals enhances the Zn-O bond covalent nature, and thus particularly short Zn-O distances are promoted.…”

“…[13][14][15] Another aspect needing to be improved is the pigment behavior in glazes for porous wall and floor tiles (monoporosa and stoneware bodies). 24 In fact, hardystonite crystallizes in the tetragonal system, space group P-42 1 m, with a general formula X 2 T 1 T 2 2 A 7 , where X is a typically large monovalent to trivalent cation (e.g., Na 1 , Ca 21 , Y 31 ), T 1 and T 2 are small divalent to tetravalent cations (e.g., Zn 21 , Mg 21 , Al 31 in T 1 ; Si 41 , Al 31 in T 2 ); and A is not only O 2À but also F À , S 2À , or N 3À . 4,[16][17][18] The present study was undertaken to search for a new crystal structure suitable to act as a blue pigment mainly in glazes rich in zinc and calcium.…”

Synthesis and coloring performance of Ni-geikielite (Ni,Mg)TiO3 yellow pigments: Effect of temperature, Ni-doping and synthesis method

“…In most cases, however, a much better understanding of the crucial role played by crystal chemical aspects is still needed to modulate or improve the coloring performance of already known or even new ceramic pigments. By an accurate knowledge and control of chromophore metal-oxygen distances [3], local environment distortions [6][7][8], cation order-disorder phenomena [9,10], structural relaxation or covalence effects [11] etc., the band gap energies [12][13][14], metal-ligand charge transfers [8] and crystal field intensities and energies on chromophore ions in a particular coordination environment can be tuned [11,12,15], and this is of paramount importance to optimize the coloring properties or to discover new ceramic pigments [16].…”

Effects of sintering temperature on Ce3+-doped Ca3Y2Si3O12 blue-emitting oxide phosphors

“…In particular, data relative to the promising host Ca 3 Y 2 Si 3 O 12 show that it is transparent in the UV region [11], and rare-earth ions doped in silicate-based hosts have been gaining much interest from researchers owing to their improved optical properties [12][13][14]. The cerium ion is the most important activator for blue emission from different phosphor host lattices [15].…”