Properties of Aluminum Powder
Aluminum is a silvery-gray metal. Aluminum powder is relatively soluble and suitable for use as a pigment. Aluminum powder paste is a mixture of pigment aluminum powder and a solvent. Its uses and properties are largely the same as aluminum powder. With a mass of 26.98, relative density of 2.55, and a purity of 99.5%, aluminum has a melting point of 685°C, a boiling point of 2065°C, and a latent heat of fusion of 323 kJ/g. Aluminum has reducing properties and oxidizes very easily, releasing heat during oxidation. Rapid oxidation releases 15.5 kJ/g of heat per gram. Aluminum is a ductile metal and easy to process. The oxide film on the surface of metallic aluminum is transparent and has good chemical stability.
Aluminum powder for pigments refers to powder with flaky particles and a surface coating treatment. It is easy to use, hence its larger production volume and usage.
Compared to other pigments, aluminum powder for pigments possesses unique characteristics, manifested in the following aspects:
1. Flake-like opacity
Aluminum powder particles are flaky, with a flake diameter to thickness ratio of approximately (40:1)-(100:1). After being dispersed onto a carrier, the aluminum powder remains parallel to the substrate. Numerous aluminum powder particles interconnect, with particles of varying sizes filling each other to form a continuous metallic film. This film opacifies the substrate while reflecting light from outside the coating, demonstrating the unique opacity of aluminum powder.
2. Shielding properties of aluminum powder
The aluminum powder dispersed within the carrier undergoes a floating motion, consistently maintaining its parallelism to the substrate being coated, forming a continuous aluminum powder layer. Furthermore, this layer exists in multiple parallel layers within the carrier film.
3. The "Two-Color Effect" of Aluminum Powder
Due to its metallic luster and parallel-to-the-coated properties, aluminum powder exhibits a "two-color effect" in its gloss and color depth within a carrier containing transparent pigments. This effect changes with the incident light angle and viewing angle.
4. The Floating Properties of Aluminum Powder
A major type of pigment aluminum powder and aluminum powder paste is the floating type, characterized by its flake-like structure floating on the coating surface.
