What are the differences between pure copper, brass, bronze, red copper and white copper? What kind of copper are copper coins made of?
In our lives, copper products can be seen everywhere, such as brass, white copper, red copper, bronze, etc. There are many kinds. So, what are the differences between so many types of copper? How should we distinguish them?
Pure copper
Pure copper is called red copper, also called red copper. It has good plasticity, excellent electrical conductivity and thermal conductivity, and can be used for hot pressing and cold pressing at the same time. It is widely used in products such as cables, wires, and special electro-etching copper for electric sparks. High-purity red copper has fine structure, low oxygen content, no sand eyes, pores, and excellent electrical conductivity. It is very suitable for electro-etching molds. After heat treatment, the electrode has no directionality and is very suitable for fine beating and precision beating.
Brass
The alloy composed of copper and zinc is called brass. If the constituent elements are only copper and zinc, then this is just the most common brass, which is usually used to make water pipes, valves, air conditioner internal and external machine connection pipes and radiators.
If the composition of brass is more than two elements, including lead, tin, manganese, nickel, iron, silicon and other elements, it is called special brass. This special brass has high hardness, high strength and strong chemical corrosion resistance.
Brass has strong wear resistance. Seamless copper tubes made of it are soft and wear-resistant. This special brass is widely used in condensers, low-temperature pipelines, submarine transport pipes, heat exchangers and other parts. Its copper content is only 62~68%.
Cupronickel
If the copper alloy uses nickel as the main added element, then we call it cupronickel. Cupronickel is divided into ordinary cupronickel of copper-nickel binary alloy and complex cupronickel with added iron, zinc, aluminum and manganese elements. In industry, cupronickel is divided into electrical cupronickel and structural cupronickel. Among them, structural cupronickel is characterized by excellent mechanical properties, good corrosion resistance and beautiful color. This kind of cupronickel is widely used, such as precision machinery, chemical machinery, and eyeglass accessories. Electrical nickel silver has good thermoelectric properties. Among them, constantan and manganese copper are commonly used materials for making varistors, precision resistors, and precision electrical instruments.
Bronze
Bronze has been used in my country for more than 3,000 years. It can be said to be the earliest alloy used in my country. The original meaning of bronze refers to copper-tin alloy. Later, for the convenience of management, all copper alloys except nickel silver and brass were uniformly called bronze. And the name of the main added element is added in front to distinguish different types of bronze. Tin bronze with tin as the main added element has excellent casting performance, good mechanical properties, and excellent friction reduction performance. It is very suitable for manufacturing turbines, gears, and bearings. Lead bronze is used as a bearing material used in current engines and grinders. Aluminum bronze has excellent wear resistance, corrosion resistance, and high strength. It is widely used in the manufacture of high-load bushings, gears, marine propellers, etc. Phosphor bronze has good conductivity, high elastic limit, and is very suitable for manufacturing precision springs and electrical contact elements.
So what kind of copper is ancient copper coins?
In ancient times, the materials of copper coins in different dynasties were also different. Bronze, brass, white copper, red copper, etc. were all used to cast copper coins. The copper coins in ancient my country were all cast with copper alloys. Because the composition of different alloys is not the same, the copper coins will also appear in different colors. Generally speaking, yellow copper coins are cast with copper-zinc alloys, and blue copper coins are cast with copper-tin alloys. In the first half of the Ming Dynasty, bronze was the most commonly used material for casting copper coins, while brass was used in the second half.
