Effect of synthesis parameters on a hematite–silica red pigment obtained using a coprecipitation route

Nano encapsulation of hematite into silica matrix as a red inclusion ceramic pigment

“…Colorimetric results in Table 1 indicate that single mineralizer addition produce similar results but NaF produces slightly better red shades, perhaps because hematite shows bigger size in this case [11][12] …”

“…4. TEM micrographs of NaF fluxed powders fired at 900 • C/3 h. (Table 1), it seems that the poor red shade of these powders is due to this nanometric size of hematite crystals [10][11][12].…”

Substitution of a fraction of zircon by cristobalite in nano hematite encapsulated pigment and examination of glaze application

“…The high thermal stability of the silicon lattices and their properties such as the sinter-ability at relatively low temperature are well known [8][9][10][11], but an important question is why the hematite-silica pigment is not applied into glaze by ceramic industry? The hematite-silica system presents better red shade pigment than hematite-zircon system, and the hematite-zircon pigment is more expensive than hematite-silica system [17][18][19].…”

“…The guest crystal becomes inactive within the host [6][7][8]. There is a restricted choice for red/pink and orange colors among synthetic inorganic ceramic pigments to be used in ceramic industry.…”

“…In particular, in order to achieve high efficiency of chromophore agent encapsulation, the matrix sintering and/or crystallization must be synchronized with the nucleation and growth of the occluded chromophore agent. Crystallization, sintering and inclusion process are thus considered to take place simultaneously, and consequently, the control of particle size of the raw powders is one of the main steps [5][6][7][8][9][12][13][14][15][16].…”