When it comes to wires, we first think of copper wires, aluminum wires, iron wires and other metal wires. They are all made of pure metal wire drawing. The reason why metals are used is that all metals have good electrical conductivity. The reason why metals have good electrical conductivity is because the metal atoms have fewer outer electrons. After they are combined into atomic groups, the outer layer of each atom also has only one or two electrons and rotates around it, so that the outer layer of the atom has only one or two electrons. There will be more electron vacancies in the layer, so the foreign electrons can easily enter and move, and the metal is easy to conduct electricity, so the wires we have seen are basically metal.
Due to the good conductivity of metal, the current wires are basically metal. Can the wires be replaced by other non-contact materials? Also possible, like carbon fiber.
Many friends know that carbon fiber is very tough, but they do not know that some carbon fibers are conductive. This is because such fibers have an atomic structure similar to graphite, and graphite is a good conductor, which is a kind of carbon element. Allotropes, each carbon atom in graphite is connected with three other carbon atoms around it, arranged in a honeycomb-like hexagonal structure, in which each carbon atom emits a free electron, so graphite conducts electricity. The performance is very good, about 100 times higher than that of ordinary non-metallic materials.
However, even so, the conduction of current in the carbon fiber composite wire does not depend on carbon fiber, because the conductivity of carbon fiber is still not as good as that of metal. The resin integrates the longitudinally arranged carbon fiber filaments into a whole, which makes the carbon fiber less conductive, so the carbon fiber here is not used to conduct electricity, but to bear weight. The structure of the carbon fiber composite core wire is similar to that of the conventional steel-cored aluminum stranded wire. It is also divided into the inner core wire and the surface aluminum wire. The core wire bears most of the mechanical stress of the wire itself, while the outer aluminum wire bears current flow task.
It turns out that the load-bearing wires in the wires are all steel wires, usually steel wire ropes twisted from 7 strands of steel wires, and the outside is an aluminum wire composed of dozens of strands of aluminum wires, but the carbon fiber composite material wire is a middle strand of carbon fiber composite material, and the outside is quadrilateral. Multi-strand aluminum wire, as shown in the figure below, the left is the steel wire aluminum wire, and the right is the carbon fiber composite core wire.
We know that although steel has good tensile strength and toughness, its density is very large, so it is very heavy, but the density of carbon fiber composite materials is much smaller, only 1/4 of steel, and its weight is only the same volume. However, the tensile force and toughness of carbon fiber are better than that of steel, generally at least twice the tensile force of steel, so the main purpose of using carbon fiber composite materials is to reduce the weight of the wire, and the same thickness of carbon fiber Because the pull is better, it can also carry more aluminum wire, making the wire or cable thicker to pass more current.
Since the carbon fiber composite wire has the above-mentioned excellent properties of low density, light weight, large tensile force and strong toughness, if this material can be used for a long time, it is likely to replace the steel wire and aluminum wire in the future. The commonly used wire, and the carbon fiber wire has a heating effect when it is energized, so it will also be used as a heating wire in some industries. Therefore, the current wire is not necessarily a metal, and the non-metallic wire will also become more and more appear more often.
Post time: Sep-15-2022