Titanium dioxide refractive index

Titanium metal is considered to be physiologically inert. When pure, titanium dioxide is relatively clear and has an extremely high index of refraction with an optical dispersion higher than diamond. 

Antireflection coatings are used over the silicon surface which, without the coating, reflects ca 35% of incident sunlight. A typical coating consists of a single layer of a transparent dielectric material with a refractive index of ca 2, which is between the index of siUcon and ait or cover material. Materials such as titanium dioxide, tantalum pentoxide, Ta20, or siUcon nitride, Si N, ca 0.08-p.m thick are common. The coating and a physically textured... 

Titanium dioxide is an amorphous white powder characterized by brightness and a very high refractive index (2.4). It is insoluble in water and organic solvents, and is a very stable material, resistant to light, pH variation, oxidation, etc. Ti02 is available in oil-dispersible and water-dispersible forms. 

Measuring the index of refraction of a material is generally done using an instrument known as a refractometer. Typical values of the index of refraction of gemstones and other materials are listed in Table 19. The relatively high index of refraction of diamond, for example, accounts for its distinct brilliance and multicolor display the index of refraction of rutile, a gemstone composed of titanium dioxide, is even higher than that of diamond, and rutile is indeed more brilliant than diamond. 

White pigments, some of rather variable composition, that have been used in the past include white lead (Cl Pigment White 1), refractive index 1.9 zinc oxide (Cl Pigment White 4), r.i. 1.9 lithopone (Cl Pigment White 5), r.i. 1.84 zinc sulphide (Cl Pigment White 7), r.i. 2.3 antimony oxide (Cl Pigment White 11), r.i. 2.2. All have been eclipsed by titanium dioxide (Cl Pigment White 6). 

The refractive index of these pigments is about 1.5, which means that they give a transparent blue when used in paints and clear plastics. Opacity can be increased by adding small amounts of titanium dioxide. The principal failing of ultramarine is its lack of resistance to acid, which can even decompose the pigment if there is sufficient available. Coated grades are made with substantially improved acid resistance. 

Iron Oxide-Mica. Iron(III) oxide is suitable, like titanium dioxide, for coating of mica platelets. It combines a high refractive index (metallic luster) with good hiding power and weather resistance. 

Titanium dioxide is found in nature in three crystal forms anastase, brooldte, and rutile. Its extreme whiteness and brightness and its high index of refraction are responsible for its widespread use as a white pigment in paints, lacquers, paper, floor covering, plastics, rubbers, textiles, ceramics, and cosmetics, see also Aluminum Catalysis and Catalysts Copper Fertilizer Haber, Fritz Iron Steel. 

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