The value of metals is directly determined by their chemical and physical properties. In the case of such an indicator as electrical conductivity, this relationship is not so straightforward. The most electrically conductive metal, when measured at room temperature (+20 °C), is silver.
But the high cost limits the use of silver parts in electrical engineering and microelectronics. Silver elements in such devices are used only in case of economic feasibility.
Physical meaning of conductivity
The use of metal conductors has a long history. Scientists and engineers working in the fields of science and technology that use electricity have long decided on materials for wires, terminals, contacts, printed circuit boards, etc. A physical quantity called electrical conductivity helps to determine the most electrically conductive metal in the world.
The concept of conductivity is inverse to electrical resistance. quantitative expressionconductivity is related to the unit of resistance, which in the international system of units (SI) is measured in ohms. The unit of electrical conductivity in the SI system is Siemens. The Russian designation for this unit is Sm, the international one is S. An electrical conductivity of 1 Sm has a section of an electrical network with a resistance of 1 Ohm.
Conductivity
The measure of the ability of a substance to conduct electricity is called electrical conductivity. The most electrically conductive metal has the highest similar indicator. This characteristic can be determined instrumentally for any substance or medium and has a numerical expression. The electrical conductivity of a cylindrical conductor of unit length and unit cross-sectional area is related to the specific resistance of this conductor.
The system unit of conductivity is Siemens per meter - Sm/m. To find out which of the metals is the most electrically conductive metal in the world, it is enough to compare their specific conductivity, determined experimentally. You can determine the resistivity using a special device - a microohmmeter. These characteristics are inversely dependent.
Conductivity of metals
The very concept of electric current as a directed flow of charged particles seems more harmonious for substances based on crystal lattices characteristic of metals. Charge carriers in the event of an electric current in metals are free electrons, and not ions, as is the case in liquid media. It has been experimentally established that when a current occurs in metals, there is nothere is a transfer of particles of matter between conductors.
Metallic substances differ from others by looser bonds at the atomic level. The internal structure of metals is characterized by the presence of a large number of "lonely" electrons. which, under the slightest influence of electromagnetic forces, form a directed flow. Therefore, it is not in vain that metals are the best conductors of electric current, and it is precisely such molecular interactions that distinguish the most electrically conductive metal. Another specific property of metals is based on the structural features of the crystal lattice of metals - high thermal conductivity.
Top best conductors - metals
4 metals of practical importance for their use as electrical conductors are distributed in the following order relative to the value of conductivity, measured in S/m:
- Silver - 62 500 000.
- Copper – 59,500,000.
- Gold - 45,500,000.
- Aluminum - 38,000,000.
It can be seen that the most electrically conductive metal is silver. But like gold, it is used to organize the electrical network only in special specific cases. The reason is the high cost.
But copper and aluminum are the most common choice for electrical appliances and cable products due to their low electrical resistance and affordability. Other metals are rarely used as conductors.
Factors affecting the conductivity of metals
Even the most electrically conductivethe metal reduces its conductivity if it contains other additives and impurities. Alloys have a different crystal lattice structure than "pure" metals. It is distinguished by a violation in symmetry, cracks and other defects. Conductivity also decreases with increasing ambient temperature.
The increased resistance inherent in alloys finds application in heating elements. It is no coincidence that nichrome, fechral and other alloys are used to make working elements of electric furnaces and heaters.
The most electrically conductive metal is precious silver, more used by jewelers for minting coins, etc. But in technology and instrumentation, its special chemical and physical properties are widely used. For example, in addition to being used in units and assemblies with reduced resistance, silver plating protects contact groups from oxidation. The unique properties of silver and its alloys often make its use justified despite the high cost.
