Pure copper is a purplish red metal, commonly known as "red copper", "red copper" or "red copper". Pure copper is ductile. Pure copper, the size of a drop of water, can be pulled into two kilometers of filaments, or rolled into almost transparent foil larger than a bed. The most valuable property of pure copper is that it has very good conductivity, second only to silver in all metals, so it has become the "protagonist" of the electrical industry.

Pure copper is more widely used than pure iron. Every year, 50% of copper is electrolytic purified into pure copper, which is used in the electrical industry. The pure copper mentioned here really needs to be very dull, with a copper content of more than 99.95%. A very small amount of impurities, especially phosphorus, arsenic and aluminum, will greatly reduce the conductivity of copper. Oxygen in copper (it is easy to mix a small amount of oxygen in copper smelting) has a great impact on the conductivity. Copper used in the electrical industry must generally be oxygen free copper.

In addition, impurities such as lead, antimony and bismuth will make the crystallization of copper unable to be combined, resulting in thermal embrittlement, which will also affect the processing of pure copper. This pure copper with high purity is usually refined by electrolysis: Impure Copper (i.e. crude copper) is used as anode, pure copper as cathode, and copper sulfate solution as electrolyte. When the current passes through, the Impure Copper on the anode gradually melts, and the pure copper gradually precipitates on the cathode. Copper thus refined; The purity can reach 99.99%.

Red copper is a kind of relatively pure copper, which can be generally regarded as pure copper. It has good conductivity and plasticity, but poor strength and hardness.

Properties and uses of brass:

Brass is a kind of copper containing other alloy components, which is cheaper than red copper. Its conductivity and plasticity are a little worse than red copper, but its strength and hardness are higher.

Brass is an alloy of copper and zinc. The simplest brass is copper zinc binary alloy, which is called simple brass or ordinary brass. Brass with different mechanical properties can be obtained by changing the content of zinc in brass. The higher the content of zinc in brass, the higher the strength and the lower the plasticity. The zinc content of brass used in industry is no more than 45%, and the higher the zinc content, the brittleness will occur, which will deteriorate the properties of the alloy.

Adding 1% tin to brass can significantly improve the corrosion resistance of brass to seawater and marine atmosphere, so it is called "naval brass". Tin can improve the machinability of brass. Lead yellow copper is what we usually call easy to cut national standard copper. The main purpose of adding lead is to improve machinability and wear resistance. Lead has little effect on the strength of brass. Carved copper is also a kind of lead brass. Most brass have good color, processability and ductility, and are easy to electroplate or paint.

In industry and civil use, different materials are selected according to different use characteristics. If wires are made, they should be soft, and red copper is better. If it is used as a connecting piece, brass shall be used for the screw.

Properties and uses of bronze:

It used to refer to copper tin alloy. Later, all copper alloys except brass and white copper are called bronze, and the name of the first major added element is often prefixed to the name of bronze. Tin bronze has good casting performance, antifriction performance and mechanical performance. It is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material for modern engines and grinders.

Aluminum bronze has high strength, good wear resistance and corrosion resistance. It is used for casting high load gears, shaft sleeves, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limit and good conductivity. They are suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to make non sparking tools used in coal mines and oil depots.

Properties and uses of white copper:

Copper alloy with nickel as the main additive element. Copper nickel binary alloy is called ordinary white copper; White copper alloys with manganese, iron, zinc, aluminum and other elements are called complex white copper. Industrial white copper is divided into structural white copper and electrical white copper. Structural white copper is characterized by good mechanical properties, corrosion resistance and beautiful color.

This kind of white copper is widely used in manufacturing precision machinery, chemical machinery and ship components. Electrical white copper generally has good thermoelectric properties. Manganese copper, constantan and copper are manganese white copper with different manganese content. They are materials for manufacturing precision electrical instruments, rheostats, precision resistors, strain gauges, thermocouples, etc.

How to distinguish red copper, brass, bronze and white copper:

White copper, brass, red copper (also known as "red copper") and bronze (cyan gray or grayish yellow) are distinguished from each other in color, and white copper and brass are easily distinguished; Red copper is pure copper (impurity <1%) and bronze (about 5% of other alloy components) which are slightly difficult to distinguish. When not oxidized, red copper is brighter than bronze, and bronze is slightly cyan or yellow darker; After oxidation, red copper turns black, and bronze turns green (harmful oxidation of water) or chocolate.

Source: tongxinbao

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