The electrical conductivity of copper directly depends on the presence of various impurities in this metal. Even if a small amount of arsenic and antimony is added to it, a sharp drop in the value of electrical conductivity occurs. But it has no significant effect on this physical quantity lead, tellurium, selenium, arsenic.
Features of the concept
The electrical conductivity of copper is not much less than that of silver, which makes this metal in demand in modern electrical engineering.
This physical quantity is a characteristic of the ability of a substance to conduct an electric current. It is associated with the electrical resistivity of the metal in direct proportion.
The electrical resistance of copper in Ohm⋅mm2 / m is at a temperature of 20 degrees 0.017. In numerical value, this is only slightly less than silver.
The electrical conductivity of copper is the inverse resistance value, is used to characterize the electrical properties of this metal. To measure it, use siemens corresponding to 1 / Ohm.
Copper production
Since copper conducts electricity, there are several ways to make this metal. Semiconductor copper is currently obtained by galvanic cleaning of ingots in special electrolytic baths. Most of the copper products used in the electrical industry are produced by rolling, drawing, pressing.
When drawing create wires having a diameter of not more than 0.005 mm, thin foil, tape up to 0.1 mm.
Copper wiring is in demand not only in the construction of apartment buildings and office premises, but also in private construction.
Interesting information
This metal is often found in nature in the form of large nuggets. Even in ancient times, people made jewelry, dishes, weapons from it. The demand for copper is explained by the ease of processing, as well as the prevalence in nature.
Initially, the process of metal extraction from its compounds was rather primitive, consisting in heating copper ore over a fire, followed by rapid cooling. Such processing led to cracking of pieces of ore, which allowed people to extract the metal itself.
As technological processes for the processing of metal ores improved, air was fed into the fires to raise the heating temperature of the natural compound. Gradually, the process began to be carried out in special designs, which became the prototypes of modern shaft furnaces.
The results of archaeological excavations testify that copper products were used already in the 10th millennium BC.
Natural compounds
Copper wires for wiring are currently made from several types of ores common in nature. For example, in the composition of boron - about 65 percent of the metal, in chalcosine - up to 80%, and in copper pyrites (chalcopyrite) the amount of copper does not exceed 30 percent.
Physical properties
High electrical conductivity of copper is one of the most important properties of this metal. Its color changes from a pale pink to a deep red color. Copper is a transition material with high thermal and electrical conductivity.
The linear thermal expansion of this metal is 0.00000017 units. Copper products have a tensile strength of 22 kg⋅s / mm 2 . The specific gravity of the metal is 8.94 g / cm 3 , the hardness on the Brinell scale is 35 kgf / mm 2 . Among the important physical characteristics of this metal, an elastic modulus of 132,000 mN / m 2 should be noted.
The magnetic properties of this metal, which is a completely diamagnetic substance, are also unique.
The temperature coefficient of resistance of copper at room temperature is 4.3 α (10 -3 / K).
Conductivity, malleability made this metal popular in the manufacture of various elements for electrical engineering. Aluminum has similar physical characteristics, so it is a raw material for creating cables and wires in modern electrical engineering.
Chemical properties
The resistance of copper, the ability of a given metal to conduct an electric current is explained by the structural features of the atom of this chemical element. Copper is located in a side subgroup of the first group of the periodic table, is a d-element.
The resistance of copper is associated with electrons located at the external energy level. The structural features also explain the specific chemical properties of this metal. At low humidity, copper is a fairly inert substance, does not exhibit high chemical activity.
When copper products are used in conditions of high humidity and the presence of carbon dioxide, metal is oxidized.
A greenish film of carbonate and copper hydroxide appears on the surface of the product (2), as well as various sulfur compounds. This film is called patina, it helps protect the product from subsequent chemical destruction.
With increasing temperature value, the formation of copper scale (oxide) occurs, which negatively affects the electrical conductivity.
Copper easily interacts with elements belonging to the halogen subgroup.
If sulfur vapor is introduced into the metal, ignition is observed. Copper is inert to nitrogen, hydrogen, carbon, even at elevated temperatures.
Of interest from a technical point of view is the interaction of this metal with iron salts, leading to its reduction. This chemical property allows you to remove copper spraying from products.
Copper forms a variety of complex compounds that are highly resistant.
Areas of use
The use of this metal is associated with its high electrical conductivity. For example, a cable is released from it. Copper has a small resistance, unique magnetic properties, easy mechanical workability, therefore, it is in demand in engineering communications and office buildings. The ability to conduct heat allows the use of this material to create heat pipes, cooling systems and air heating.
Copper is the material that is indispensable in the production of coolers used to lower the temperature of personal computers. Metal structures that contain copper elements have low weight, excellent decorative properties, and therefore are suitable for use in architecture, and for the manufacture of a variety of decorative elements in the interior, and for creating electrical wires.
Conductor Features
In order to understand the essence of electrical conductivity, let us dwell on the characteristics of conductors. These include materials that can conduct electrical current. Copper belongs to the conductors of the first kind, since with increasing temperature there is a decrease in electrical conductivity. The quality of the conductor material is affected by mechanical, thermal, electrical properties. For a metal such as copper, all these indicators have good values, which makes the metal in demand in various fields of electrical engineering.
Plasticity of copper, ease of processing, good viscosity, chemical resistance allow you to create different types of products from this metal for technical needs.
Varieties
For the manufacture of blister copper, electrolytic reduction of a metal from a solution of copper sulfate is used. Pure metal is necessary for radio and electrical engineering. Depending on the percentage of impurities, there are brands: M0 and M1. In the first case, the quantitative content of pure metal is 99.95 percent, for the second option - 99.9 percent.
Among the main physical properties that characterize these brands of copper, we note:
- density 8900 kg / m 3 ;
- melting point 1083 ° C;
- high mechanical strength;
- excellent machinability;
- high resistivity 1.7241 ⋅ 10 -8 Ohm ⋅ m.
When impurities are introduced into the composition of a pure metal, the resistivity increases substantially, while the electrical conductivity decreases.
For example, in the case of the introduction of 0.5% aluminum and nickel, the resistivity increases by 40 percent.
Conclusion
Copper differs from other current conductors in high electrical conductivity, low resistance, which makes it popular in modern electrical engineering.
Conducting conductors, cables, foil getinaks for printing devices, sheets, strips, wire - this is not a complete list of those products that are made from copper.
In addition to the widespread use of the metal itself, its main alloys are also used. For example, cadmium bronze is used to create collector plates and electrical contacts.
Phosphor bronze is needed for the production of springs in devices and electronic devices. A mixture of copper and beryllium allows you to create clamps, sliding contacts, current-carrying springs.
Tin bronze is called telephone, since it is from it that the wire used for the telephone cable is created.
Stripes and sheets are made from copper-zinc alloys . This material has a greater electrical resistivity, so the alloy has great strength.
Among the many uses of copper, the electrical industry is of particular importance. This metal is used to create electric wires of various diameters and sizes, suitable for the manufacture of modern electrical and radio devices of the highest accuracy. To increase electrical conductivity, engineers monitor the purity of the metal, prevent the penetration of additional impurities.