Perovskite pigments

Overall, some of these perovskites exhibit a coloration that is comparable to inorganic pigments currently utilized by the industry (Figure 12.1). In other cases, however, the color strength is too weak to support their use as colorants. At all events, the only perovskite pigment produced at industrial scale is the red Cr-YAlOs [9,10,12,29,44-47]. Thus, the following sections will focus on yttrium orthoaluminate and related compounds. 

A number of new high temperature pigments used in ceramic has led the search for the perovskite pigments of lanthanides. This system has been first developed in 1984-1986 in the red perovskite pigments lanthanides and recently in 2000 red, reddish and pink color... 

A. Kalendova, D. Vesely, and P. Kalenda, Pigments with Ti -Zn, Ca, Mg -based on mixed metal oxides with spinel and perovskite structures for organic coatings, Pigment and Resin Technology 36(1) 3-17, 2007. 

Gratzel M (2013) Perovskite nano-pigments and new molecularly engineered porphyrin light harvesters for mesoscopic solar cells. Hybrid and Oiganic Photovol-taics Conference (HOPV13), Sevilla, Spain, 7 May 2013... 

Several perovskite compounds have been proposed as pigments (Table 12.1). They are both oxide and non-oxide phases with crystal symmetry spanning from ideal cubic perovskite to increasingly distorted hexagonal, tetragonal, and orthorhombic types, down to peculiar cases of monoclinic and triclinic lattices. 

Figure 12.1 Chromatic parameters (<3 6 plane of the CIE Lab coordinates) of oxide (a) and non-oxide (b) perovskites proposed as pigments. The numbered fields represent the color space of industrial Inorganic pigments black Fe-Cr-Co-Ni spinel (1), magenta Cr-malayaite (2), pink hematite-zircon (3),...

The Mn-doped YInOs perovskite develops an intense blue hue that is comparable to industrial cobalt pigments, although it is free of yellow overtint [19]. The best color corresponds to the YIno,9Mno,i03 composition, which was proposed for high-performance applications, due to the very high cost of precursors (particularly indium oxide). 

Although it is known that various mineralizers can affect the Cr-YAP color [10-13,29-34] and the most effective are complex mixtures, such as NaF -F MgFal-LiaCOs (Figure 12.15a), no systematic data on single mineralizer are available in the literature. For this reason, a comparative study was carried out by synthesizing the Cr-YAP pigment with various amounts and types of additives, providing cations with different size and valent state (Mg ", Ca, K, Ba, La " ) and different anions (Cl, F, CO3). The addition of a mineralizer proved to be necessary to improve the synthesis yield The amount of perovskite formed is drastically increased from 60 wt% without minerahzer to 85 wt%... 

Iron and chromium doped perovskite (CaMOs M = Ti, Zr) ceramic pigments, effect of mineralizer. Ceram. Int, 38, 4453-4460. 

Cordoncillo, E., Escribano, P., and Carda, J.B. (2003) Study of solid solutions, with perovskite structure, for application in the field of the ceramic pigments. J. Eur. Ceram, Soc., 23, 213-220. 

Kar, J.K., Stevens, R., and Bowen, C.R. (2008) Processing and characterisation of various mixed oxide and perovskite-based pigments for high temperature ceramic colouring application. /. Alloys Compd., 461, 77-84. 

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