Transparent Cobalt Blue

Transparent cobalt blue (Color Index Pigment Blue 28 77346) consists of minute, very thin, more or less hexagonal flakes. It is an ideal spinel with the composition Me Me 204. The spinel structure is shown in Section 3.1.3. 

The hydroxides are filtered, washed, dried, calcined at ca. 1000 °C and finally dry-ground [5.193]. 

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Transparent Cobalt Blue. Cobalt blue [1345-16-0] C.I. Pigment Blue 28 77346, is also produced as a transparent pigment by precipitating cobalt and then aluminum as hydroxides or carbonates from salt solutions using alkali. The hydroxides or carbonates are then filtered, washed, dried, and calcined at 1000°C [5.278]. It is important to carry out the precipitation with high dilution and to distribute the alkali uniformly throughout the entire reaction volume. 

Transparent cobalt blue pigments have the form of small tiles (primary particle size 20-100 nm, thickness ca. 5 nm, specific surface area (BET) ca. 100 m2/g). They are resistant to light and weather and are used in metallic paint, but are of little importance. 

The Morpho Butterfly, the Sun Butterfly in a Japanese name, living in a basin of the River of Amazon enchants people all over the world with its transparent cobalt blue color and beatiful metalic luster. 

Transparent cobalt aluminum blue is prepared by the precipitation of diluted solutions of cobalt and aluminum with alkaHes. The formed precipitate of hydroxides is washed, filtered off, dried, and calcined at about 1000°C. 

Transparent Cobalt Green, Analogous to cobalt blue a transparent cobalt green spinel C.I. Pigment Green 19 77335 can be manufactured. 

The green as well as the blue transparent cobalt pigments are used as filter materials for cathode ray tubes (CRT) [5.279]. 

For an opaque surface, transmittance t is zero. This reduces Eq. (24.2) to a + p = 1, and thus we only need to determine p. While this assumption is often valid and simplifies things greatly, there are pigments with nonzero transmission. An example in the visible region would be cobalt blues. In the infrared region we cannot rely on our eyes it is possible for a pigment to be partially transparent even if it is opaque in visible light. 

Two blue pigments can be prepared in transparent form cyanide iron blue and cobalt aluminum blue. These pigments are used in achieving a blue shade of the metal effect pigments in metallic paints. Transparent cyanide iron blue is prepared by a precipitation reaction similar to the one used for the preparation of the opaque pigment, but considerably lower concentrations of solutions are used. It is produced by Degussa (Germany), Manox (U.K), and Dainichiseika (Japan). 

Cobalt aluminum blue, transparent, 19 412 CobaltCII) aminobenzoate, uses, 7 239t CobaltCII) ammonium sulfate, uses, 7 239t CobaltCII) arsenate, uses, 7 241t Cobalt-base corrosion-resistant alloys,... 

Blue Transparent Glass.—Sis hundredweight of hatch colored with two pounds of oxide of cobalt. 

Codein is a very powerful base it turns red litmus paper blue, and precipitates the oxides of lead, iron, cobalt, and nickel from their solutions. It is precipi. tated from the solutions of its salts by potassa and by ammonia in the latter case, however, It does not fall immediately, but is slowly deposited as small transparent crystals. ... 

Phosphoric acid Nickel oxides and cobalt oxides An ingredient of white opal glass or promotes transparency to u.v. or opacity to i.r. when used with ferrous iron Brown, purple, deep blue... 

Transparent samples do not absorb the radiative energy properly. For this reason, several procedures were utilized to make the sample more opaque. One such procedure consists of adding into the sample powdered graphite [21a] or a metal such as nickel [22], This addition can, however, modify the course of the pyrolysis by catalytic effects or side reactions. A different procedure consists of depositing the sample in a very thin layer on a support that absorbs the radiation generating heat. In particular, a blue cobalt-glass rod has been used [22] as a support for the sample, with temperatures attaining 900-1200° C. 

Prior to the discovery of Prussian blue, there were three blue pigments available to painters azurite [ 03(011)2(003)2], smalt (a complex cobalt and arsenic compound), and ultramarine blue, which has the complex formula of CaNa7Al6Si6024S04. Prussian blue quickly came to be valued by painters for the intensity and transparency of its color, and it is commonly found in works painted after the early 1700s. 

If the laser radiation is not absorbed by the sample (e.g., with transparent materials), a substance performing the function of absorption centres (such as powdered carbon or nickel) is introduced into the sample for the latter to be pyrolysed. For example, in ref. 93 it was proposed to decompose transparent polymers (e.g., polyethylene, polystyrene) exposed to a laser beam by placing the samples made in the form of a thin film on the flat surface of a blue cobalt glass rod. The light products are formed primarily in the plasma torch - the rapidly frozen plasma induced by the laser radiation. These products are essentially low-molecular-weight gases whose analysis permits the sample composition to be determined. Such an analysis is known as plasma-stoichiometric analysis [94]. 

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