niosh titanium dioxide

Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

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The primary function of TiO2 in pigment production is its exceptional ability to provide brightness and opacity. When added to paints or coatings, it enhances their hiding power by reflecting light back to the observer's eye. This property not only improves the aesthetic appeal of the product but also reduces the amount of colorant needed, resulting in cost savings for manufacturers. Moreover, TiO2's high refractive index ensures that even small quantities can significantly impact the final appearance of the product.

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