Metal Pigments

Metal pigment powders have the following types: aluminum powder (silver), copper powder (gold), zinc powder, lead powder, titanium powder and iron powder.

• Aluminum powder

As a common metal pigment powder with silver-white metal luster and decent covering capability, aluminum powder can be used to make metal paints, metal coatings and metal inks, granting them with unique metal texture and luster, as well as decorative materials, such as metal wallpapers, metal floors and metal ceilings.

• Copper powder

As a metal pigment powder with red metal luster, copper powder can be used to make metal paints, metal coatings and metal inks, granting them with unique metal texture and luster, as well as decorative materials, such as metal wallpapers, metal floors and metal ceilings. In addition, it can also be used to make metal crafts and metal sculptures, granting them with unparalleled artistic value.

• Silver powder

As a metal pigment powder with silver-white metal luster, silver powder can be used to make metal paints, metal coatings and metal inks, granting them with unique metal texture and luster, as well as decorative materials, such as metal wallpapers, metal floors and metal ceilings. In addition, it can also be used to make jewelry and metal crafts, granting them with unparalleled beauty and value.

• Gold powder

As a metal pigment powder with gold metal luster, gold powder can be used to make metal paints, metal coatings and metal inks, granting them with unique metal texture and luster, as well as decorative materials, such as metal wallpapers, metal floors and metal ceilings. In addition, it can also be used to make jewelry and metal crafts, granting them with unparalleled beauty and value.

• Iron oxide pigment powder

As a common pigment, iron oxide pigment powder is commonly used in such industries as dyeing, coating and building materials. Iron oxide pigment powder is divided into many varieties, including red, yellow, brown, etc. Due to decent covering capability and color stability, it is widely used.

• Titanium powder

As a metal powder made of titanium, titanium powder is a silver-gray irregular powder and is commonly used in such industries as aerospace, spraying, metallurgy and firework.

• Different pigment compositions

The main component of metal pigment is metal, such as silver powder, copper powder and aluminum powder, and its color presents metal luster and reflective effect. Pearlescent pigments are composed of several thin layers of substances such as stannate or titanium dioxide, and the surface is coated with metal oxides or other dyes. They can undergo such phenomena as interference refraction, reflection and transmission under light irradiation, thus a shiny pearlescent effect is generated therefrom.

• Different wavelengthsof reflected light

Since the color of metal pigments is formed by the superposition of metal and ambient luster reflected, the wavelength of reflected light is relatively single, generally bluish violet, golden yellow and silver-white in visible light. While since the color of pearlescent pigments is formed by the refraction and interference of light, the wavelength of reflected light is relatively wide and the photochromic form is rich. It can present a variety of colors such as iridescence, silver-white, golden yellow and bluish violet.

• Different effects

Metal pigments have effects mainly manifested in metal texture and luster and are characterized by decent covering capability and discoloration. They are commonly used in such industrial fields as coating, plastics, rubber and printing and can also be used as decorative pigments to make cosmetics and baked goods. While with a unique luster, pearlescent pigments enable the surface of items to appear more prominent and three-dimensional. They are commonly used in such industries as beauty cosmetics, coating, plastics and printing.

• Different scopesof application

Since metal pigments are applicable for large-area coating and not applicable for coating tiny parts, and they are also anti-corrosive and lustrous, they are mainly used in industrial and mechanical fields, such as decoration and anti-corrosion treatment of car bodies and rims. While pearlescent pigments are applicable to a wider range of fields, and are commonly used in cosmetics, home decoration and handicrafts, which can make items present more unique and beautiful visual effect.

Metal pigments and pearlescent pigments each have unmatched characteristics and scopes of application. Therefore, you should make selection based on specific requirements to achieve the optimal effect in use.

You should prepare metal pigment powders into metal pigment slurry prior to use. There are many ways to dilute powders taking copper-gold powder as an example, among which the most common method is as follows:

(1) Add an appropriate amount of copper-gold powder and stir slowly, and then add 1:1 or 2:1 solvent to the copper-gold powder for several times;

(2) Stir under low shear force for about 15 minutes until it becomes paste;

(3) Add an appropriate amount of gold-adjusting oil and stir thoroughly to mix well;

(4) Adjust to the required viscosity with solvent;

(5) In order to avoid curling and breaking of flaky copper-gold powder particles during the dispersion process, which would reduce optical effect, it is best to use a blade stirrer or a disc disperser and stir at medium speed.

Compared with other pigments, metal pigments possess their particularity. Many metal pigments are used as decorative pigments, such as copper-zinc powder and aluminum powder, since powdered metal pigments are composed of metals or alloys and have bright metal luster and color.

Most metal pigments are flaky powders. When they are mixed into substrates and applied to form films, they are parallel to the surface of the coated object like fallen leaves covering the ground, overlapping and covering each other, and arranged in multiple layers, forming a barrier. The metal scales fill the tiny pores of the film-forming object, creating a “maze effect” that prevents the penetration of harmful gases or liquids from the outside into the coating, protects the coating and the coated objects, and improves the anti-corrosion ability of the coating’s physical shielding. Metal powder can reflect more than 60% of the UV rays in sunlight, so it can prevent the coating from aging due to UV radiation, which is beneficial to prolonging the life of the coating. Meanwhile, its reflected light can play a flashing and decorative role.

Metal pigments are extremely fine powders, mostly in the form of scales, as well as spheres, teardrops, and branches, all of which are related to their manufacturing methods. Metal powders must be surface treated to have pigment properties, such as dispersibility and covering capability. Different surface treatments can make the surface of metal pigments lipophilic or hydrophilic to meet the requirements of different coatings.

Most metal pigments are manufactured by physical processing, which converts pure metals or alloys into specific powders, such as converting solid, liquid and gaseous metals into powders.

(1) Convert the metal from gas phase into powder, such as manufacturing zinc powder and ultrafine aluminum powder by sublimation.

(2) Convert the metal from liquid phase into powder, such as manufacturing aluminum powder, zinc powder and copper-zinc powder by pneumatic atomization.

(3) Convert the metal from solid phase into powder, such as manufacturing magnesium powder, aluminum powder, zinc powder, stainless steel powder and iron powder by cutting and ball milling.

The selection of different powder manufacturing methods should be based on the physical properties of the metal being processed, such as melting point, vaporization temperature, hardness and ductility, and also according to the structural characteristics of the product powder, such as particle size, shape, etc. From an economic and reasonable perspective, you should select a method with the lowest processing cost and energy consumption. The selection of processing methods should also focus on its safety. Most metal powders have good reducibility but rapid oxidation releases a lot of heat and generates high temperature, which is prone to explosion. Metal powders, especially heavy metal powders, are harmful to human health, so ensuring safety is an important principle in selecting processing methods.