the Shapes of Aluminum Powder

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Aluminum powder is mainly obtained by atomization of aluminum ingots after thermal melting at high temperatures. Aluminum powders obtained by this method are usually irregular aluminum metal particles. Then what are connections between the shapes of aluminum powder and its use?

As a large class of metallic pigments, aluminum powder is lightweight with high floating force, strong hiding power and good reflective properties of light and heat, so it is widely used, highly demanded in many varieties. In fact, these characteristics and uses of aluminum powder are inseparable from its shapes. Generally speaking, aluminum powder obtained by sieving, in addition to different from particle sizes, can be broadly grouped into four categories, which are arborization, thorn-spherical shape, spherical or teardrop-shaped, hemispherical shape.

Arborization

After being grinded, aluminum flake of the dendritic aluminum is quite irregular. Its particle size is generally smaller and easy to break deflection. Therefore, it is more difficult to reflect its metallic luster, and the surface smoothness of aluminum flake is relatively poor. Since it can be largely obtained after sieving, tits price is comparatively low. Whether its white brightness and characteristic are good or bad depends largely on the level of techniques and technology, mostly used as a floating aluminum paste and non-leafing in industrial production. It mainly applies into anti-corrosion paints, marine paints, industrial coatings and printing inks.

Thorn-spherical shape

For this kind of aluminum metal powder, its aluminum flake is mostly flake. Its particle size is mostly quite fine, generally less than several um not exceeding 20um after grinding. Its aluminum flake is more regular than “popcorn-shaped”. Among them, there are finer and more uniform distribution products. Therefore, its value is higher than that of the dendritic aluminum, mostly used as metal-effect aluminum paste or high-grade floating silver paste in industrial production, where market prices of excellent varieties are not less than that of “silver round”. Such aluminum pastes in the mid-range product (standard, fine silver) are used as a plastic paint, plastic sheet paint and appliance paint. However, luxury products (metal effect, silver), due to fine particle sizes, good whiteness and high hiding power, are used to make high-gloss or matte effect aluminum plate coatings, coil coatings, home appliances plastic paint and automotive paint, etc., with excellent economic applicability of high decorative paints.

Spherical or teardrop-shaped

With a special surface treatment process and grinding, aluminum flake is mostly circle or oval. Because such aluminum powder is small in volume in regular shape and smooth in aluminum paste surface, and can reflect to the white brightness and metallic of aluminum metal itself to the greatest extent, so the raw materials cost relatively high, mostly used as metallic glittering aluminum pastes. This type of aluminum paste, according to the different effects of particle surface treatment technology, is widely used in high decorative paints such as metal paint, plastic paint, dry paint, exterior coatings, coil coatings, appliance coatings, and automotive paints, etc..

Hemispherical shape

Such aluminum powder is processed into aluminum paste. Its aluminum flake is between “snowflake” and “silver circle”. Its volume is slightly more than spherical or teardrop-shaped aluminum powder. Besides, aluminum pastes made of such aluminum powder can make aluminum flake surface smoother than that of “silver circle”, with white brightness and metallic slightly different. So, such aluminum powder belongs to the universal flash metal in the metal flash-type silver paste. For lower-priced products, its purposes are similar to the flash-type silver paste, mostly used as common decorative paints.

This shows the shapes of aluminum powder are directly determine its purposes, so it is important to control the shapes of the aluminum powder in the production process.