Лако-красочные материалы — производство

There is one commercially important chromite-based green pigment in this class. This is a cobalt chromite green, C. I. Pigment Green 26. These pigments are spi­nels made from cobalt(II) oxide and chromium oxide green, with the general for­mula CoCr2O4. Common modifiers include aluminum, titanium, magnesium, and zinc oxides. The cobalt(II) ions in the spinel are tetrahedrally coordinated, providing the green chromium oxide base with a bluish hue. Generally these col­ors range from bright green-blue to a dark forest green.

The major use of cobalt chromite greens is in camouflage applications. In the near IR region (700 to 1000 nm), the pigments exhibit a reflectance similar to that of some natural backgrounds. Cobalt chromites have proved useful in preparing greenish colors that match ambient IR signatures.

5 Complex Inorganic Color Pigments: An Overview

References and Notes

1 Simple metal oxide colorants are those containing only one type of metal such as iron(III) oxide red, titanium dioxide white, and chromium(III) oxide green, according to this scheme.

2 The elements in the periodic table in which the d-electron shell is filled are all metals. These elements are referred to as the transition metals.

3 F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, 4th edn., 1980,

pp. 657-658, John Wiley & Sons, New York.

4 Pigment types are commonly referred to by their Colour Index (C. I.) designa­tion, an internationally recognized nomenclature. These names are found in Colour Index, International Pigments & Solvent Dyes, Society of Dyers and Col­ourists, 3rd. edn., 1997, Bradford, West Yorkshire, England.

5 Peter A. Lewis, (ed.), Pigment Handbook, Vol. 1, Properties and Economics, 2nd edn., 1988, pp. 22-24, John Wiley & Sons, New York.

6 Swaraj Paul, Surface Coatings Science and Technology, 1985, pp. 324-326, John Wiley & Sons, New York.

7 The prefix ferri — in chemistry denotes iron in the +3 oxidation state, as it is in the rediron(III) oxide, Fe2O3. It is de­rived from the Latin word “ferrum” for iron.