2/15/2024 0 Comments Cobalt blue color pegmint![]() In most water-based paint, cobalt blue is a semi-transparent pigment with moderate tinting strength. Permanence and CompatibilityĪll cobalt blue pigments are chemically inert, absolutely insoluble, have good hiding power and excellent heat stability, and show very good lightfastness and weather resistance. The hardness of spinel minerals is around 8 (chalk has a hardness of 2-3), specific gravity is 3.5-4.1 and it is transparent to opaque with a vitreous to dull luster. They have an imperfect octahedral cleavage and conchoidal fracture. Spinel minerals form octahedral crystals that are usually twinned. The spinels are a class of minerals that crystallize in the cubic (isometric) crystal system with the oxide anions arranged in a cubic close-packed lattice and the cations occupy some or all of the octahedral and tetrahedral sites in the lattice. Blue-green hues are produced by introducing chromium (III) oxide, partially replacing the aluminum (III) oxide in the basic cobalt blue, forming Pigment Blue 36.Īll of them form the crystalline modification of spinel during calcination. The lighter-colored cobalt blue is prepared by addition of zinc (II) oxide to the ingredients used for the basic pigment, forming Pigment Blue 72. ![]() The result is a large variety of cobalt blue pigments that differ in their tinting strength or hues (reddish or greenish blue), depending on the exact chemical composition. The variations are produced by a partial substitution of the cobalt by chromium and zinc, either alone or in combination with each other. The basic cobalt blue color, Pigment Blue 28, is produced by high-temperature calcination of cobalt (II) oxide (CoO) and aluminum oxide (Al2O4). These variations differ in their tinting strength and hue. SourceĬobalt blue is cobalt aluminate blue spinel (Pigment Blue 28 or PB 28) with the chemical structure CoAl2O4 of which there are three basic modifications (Pigment Blue 36:1, Pigment Blue 36 and Pigment Blue 72), in which parts of the cobalt are substituted either alone or in combination with chromium and zinc. Techniques for manufacturing cobalt blue, the chemically pure salt of cobalt and aluminum oxide, were developed in 1802. The earliest modern history of cobalt aluminate pigments commences with Leithner in Vienna who appears to have discovered the basic process of calcining cobalt oxide and alumina (aluminum oxide) in 1775. Cobalt salts were first identified in the eighteenth century. Probably it contains nickel and zinc, which were found by x-ray spectroscopy. ![]() The spinel phase has a much lower cobalt/aluminum ratio than modern cobalt blue pigments. Origin and HistoryĬobalt aluminate is identified as the blue pigment on 30 polychromic shards of the 18th dynasty from Theben and Tell el Amarna. Conforms to ASTM D-4236.įor a detailed explanation of the terms in the table above, please visit. Do this by avoiding ingestion, excessive skin contact, and inhalation of spraying mists, sanding dusts and vapors from heating. Always protect yourself against potentially unknown chronic hazards of this and other chemical products by keeping them out of your body. There are no acute or known chronic health hazards associated with the anticipated use of this product (most chemicals are not fully tested for chronic toxicity). Spanish: cobalto espinela de aluminato azules Typical applications (non inclusive) are liquid and powder coatings, inks, dispersions, concrete, plastics, and other applications where equivalent pigment chemistry is used. It is compatible with most resin systems and polymers, and is nonwarping. It has exceptional durability and hiding power, and is generally used in applications where resistance to heat, light, and weather are needed. They have excellent chemical and heat stability, and can be used in chemically aggressive environments and exterior durable applications without color fade.Ĭobalt aluminate blue pigment has good ultraviolet and visible light opacity, is chemically inert, heat resistant, and stable to ultraviolet light. Cobalt blue pigments are the most durable blue pigments commercially available. ![]() It may include any one or more modifiers MgO, ZnO, Li2O and/or TiO2. Cobalt Aluminate Blue pigment is cobalt aluminate blue spinel (CoAl2O4) is produced by calcining, at high temperature, a mixture of cobalt (II) oxide, and aluminum (III) oxide in varied ratios forming a interdiffused crystalline spinel.
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