Bronze Powder is chemically classified as an inorganic colorant. This pigment is a finely powdered metal consisting chiefly of copper or an alloy of copper and zinc, with small amounts of aluminum or tin. It is widely used in various industrial and cosmetic applications due to its distinctive metallic color.

Chemical Composition and Structure

Bronze Powder is an inorganic compound primarily composed of copper (Cu) or an alloy of copper (Cu) and zinc (Zn), with minor additions of aluminum (Al) or tin (Sn). This combination imparts the pigment with unique metallic properties and color characteristics.

Physical Properties

This pigment typically appears as a fine metallic powder with a characteristic copper or bronze color. It has high density, excellent opacity, and a reflective metallic sheen. Bronze Powder is known for its stability, resistance to light and heat, and non-reactivity, making it suitable for long-lasting applications.

Chemical Industrial Synthesis Process

• Preparation of reagents. The main raw materials include pure copper or an alloy of copper and zinc (brass) with small amounts of aluminum or tin.
• Melting. The production of Bronze Powder begins with the melting of metals in a high-temperature furnace. The pure copper or copper-zinc alloy is heated until it becomes liquid.
• Alloying. If an alloy is used, small amounts of aluminum or tin are added to the molten metal to achieve the desired properties.
• Atomization. The molten metal is then atomized in a cooling chamber. This process involves the use of high-pressure gas (such as air or nitrogen) to break up the liquid metal into small droplets that rapidly solidify into fine particles.
• Collection. The powdered metal particles are collected in a powder collection system.
• Grinding and sieving. The collected particles are further ground and sieved to ensure a uniform and fine particle size.
• Washing. The metal powder is washed with appropriate solvents to remove any surface impurities.
• Drying. The washed powder is dried at controlled temperatures to remove residual moisture.
• Classification. The dried powder is classified to separate the desired particle sizes using sieves or air classifiers.
• Stabilization. The Bronze Powder powder is stabilized to ensure its stability during transportation and storage, preventing oxidation and aggregation.
• Quality control. The Bronze Powderundergoes rigorous quality testing to ensure it meets standards for purity, particle size, and safety. These tests include chemical analysis, spectroscopy, and physical tests to determine rheological properties.

What it is used for and where

Cosmetics

Restricted cosmetic ingredient as IV/132 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

• Copper

Cosmetics - INCI Functions

• Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

Bronze Powder is used in cosmetic products such as eyeshadows, lipsticks, and nail polishes due to its metallic luster and color. 

Industrial Applications

Paints and Coatings: In the paint industry, copper and its alloys are used to create metallic finishes and enhance UV resistance. The pigment's stability and reflective properties make it ideal for decorative and protective coatings.

Plastics and Polymers: This pigment is employed in the production of plastics and polymers to achieve metallic effects and improve color uniformity. It is commonly used in products like automotive parts, packaging materials, and consumer goods.

Ceramics and Glass: Bronze Powder is used in the production of ceramics and glass to achieve metallic finishes and enhance the overall appearance of the products. It is particularly valued for its stability during high-temperature processes.

Inks: The pigment is also used in printing inks to produce metallic and reflective effects, ensuring high-quality and visually appealing prints.

Safety

Bronze Powder is generally considered safe for use in consumer products when handled according to proper safety procedures. While it is non-toxic, precautions should be taken to avoid inhalation of the fine powder and minimize direct contact with skin and eyes. Environmental considerations include ensuring sustainable sourcing of raw materials and proper disposal of waste products.

Molecular Formula  Cu

Molecular Weight   63.55 g/mol

CAS   7440-50-8

 EC number   231-159-6

UNII   789U1901C5

Synonyms:

Pigment Metal 2

Bronze Powder

Copper Powder

CI 77400