Inorganic pigments based on hibonite structure, synthesis and usages


The present invention relates to a blue inorganic pigment which is based on the structure of hibonite consisting of a calcium hexaluminate, with the simplified formula CaAl12O19. The synthesis of hibonite structure with chromophore ions incorporated in the crystal net (eg. Ni), by solid state reaction, partially replacing Al3+ cations, enables obtaining a solid dissolution pigment with suitable chemical and thermal stability and ability to impart color to a wide range of products including ceramic products that need to be processed at high temperatures. In this invention, the synthesis of this structure when combined with anorthite structure also allows a substantial reduction in processing temperature. Furthermore, the concentration of the chromophore species is relatively low, which reduces the final cost of the pigments. The synthesis process used to obtain this pigment comprises the following steps: raw materials dosing and mixing, mixtures calcination, washing and grinding. The present invention is mainly intended to be used by pigments producers and by the glazing industry, with application in the areas of decoration, particularly in the ceramics industry.

Innovative aspects & main advantages

The present invention describes the development of novel blue inorganic pigments, based on the hibonite (calcium hexaluminate) structure. This structure hosts distinct chromophores, such as Ni and Co, but the required amounts are in general much lower than in commercial pigments (e.g. Co/Al spinel). As a consequence, the production costs are lower and potential toxicity/leaching problems of transition metals are minimized. By using Co, the blue hue is stronger; by contrast, the use of Ni will give light turquoise tonalities.


The main application of this invention (the potential commercial/industrial sectors) is focused on the pigments producers, while the colorants might be applied in distinct products, such as ceramics, glazes and glasses.


Batista, João; Ribeiro, Manuel; Costa, Maria;

Our Inventors


Universidade de Aveiro
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