What are the differences between red copper, brass, bronze and white copper? What are their respective characteristics?

White copper, brass, red copper (also known as "red copper"), and bronze (bluish gray or grayish yellow) are distinguished by color, among which white copper and brass are very easy to distinguish. It is slightly difficult to distinguish between red copper (pure copper with impurities < 1%) and bronze (with other alloy components around 5%). When not oxidized, red copper has a brighter color than bronze, while bronze is slightly bluish or yellowish and darker. After oxidation, red copper turns black, while bronze is either bluish green (harmful oxidation due to excessive moisture) or chocolate color. Bronze originally referred to a copper-tin alloy. Later, all copper alloys except brass and white copper were called bronze, and the name of the first major additive element was often prefixed before the name of bronze. Tin bronze has excellent casting properties, anti-friction performance and mechanical properties, making it suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material in modern engines and grinding machines. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used for casting high-load gears, bushings, Marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limits and good electrical conductivity, making them suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to make non-sparking tools for use in coal mines, oil depots, etc.

White copper is a copper alloy with nickel as the main additive element. Copper-nickel binary alloys are called common white copper. White copper alloys with elements such as manganese, iron, zinc and aluminum added are called complex white copper. Industrial white copper is divided into two major categories: structural white copper and electrical white copper. The characteristics of structural white copper are good mechanical properties and corrosion resistance, as well as an attractive color. This kind of white copper is widely used in the manufacture of precision machinery, chemical machinery and ship components. Electrical white copper generally has good thermoelectric properties. Manganese copper, constantan and kaotong are manganese white copper with different manganese contents. They are materials used in the manufacture of precision electrical instruments, rheostats, precision resistors, strain gauges, thermocouples, etc. White copper has exceptionally good mechanical and physical properties compared to other copper alloys. It features excellent ductility, high hardness, beautiful color, corrosion resistance, and deep drawing performance. The drawback is that the main added element - nickel - is a scarce strategic material and its price is relatively high. First, let's get to know pure copper. Red copper is the type of copper with the highest copper content, reaching 99.5% to 99.95%, and thus it can also be called pure copper. Pure copper is highly pure elemental copper. Because pure copper forms a purple oxide film on its surface after oxidation, it is also called red copper or purple copper, and it has a rose red color. Red copper is generally refined by electrolysis, and the purity of the refined copper can reach 99.99%. Meanwhile, red copper has excellent plasticity and is soft in nature, making it convenient for shaping and installation. Red copper is highly malleable. A pure copper drop the size of a water can be drawn into a fine wire as long as two kilometers or rolled into a foil larger than a bed and almost transparent. In terms of performance, red copper has excellent plasticity and good electrical and thermal conductivity, so it is often used in cables, wires, heat dissipation components, etc.

Brass is a type of copper containing other alloying components. Its electrical conductivity and plasticity are slightly inferior to those of red copper, but its strength and hardness are higher. From the appearance, the surface color of brass is yellow, so it is called brass.

Brass is an alloy of copper and zinc. The simplest brass is a binary alloy of copper and zinc, known as simple brass or common brass. By varying the zinc content in brass, brasses with different mechanical properties can be obtained. The higher the zinc content in brass, the higher its strength and the slightly lower its plasticity. The zinc content of brass used in industry does not exceed 45%. Any higher zinc content will cause brittleness and deteriorate the performance of the alloy.

Adding 1% tin to brass can significantly enhance its resistance to corrosion from seawater and Marine atmosphere, thus it is called "naval brass". Tin can also improve the machinability of brass. Lead brass, which is commonly known as free-cutting national standard copper, is mainly added with lead to improve machinability and enhance wear resistance. Lead has little effect on the strength of brass. Engraved copper is also a type of lead brass. Most brasses have good color, workability and ductility, and are easy to electroplate or paint.

In both industrial and civil applications, different materials should be selected based on different usage characteristics. If it is for making wires, a relatively soft texture is required, and red copper is a better choice. When making connecting parts, brass is mostly chosen for the places where screws are installed.

Bronze is the earliest alloy in the history of metal smelting and casting. It is an alloy made by adding tin or lead to pure copper (red copper), which has special importance and historical significance. Compared with pure copper (red copper), bronze has higher strength and a lower melting point (when 25% tin is used to smelt bronze, the melting point will drop to 800℃). The melting point of pure copper (red copper) is 1083℃. Bronze has good castability, is wear-resistant and has stable chemical properties.