With the development of magnesium smelting and processing technology and the decline of production costs, China's magnesium industry will be poised for development. my country's magnesium alloy industry is in a stage of rapid development. Magnesium, as an excellent material for weight reduction, energy saving and environmental protection, will play an important role in the future sustainable development of the world.
Expanding the application of magnesium will not only be a world trend, but also an opportunity for China. For example, the cast magnesium alloy sacrificial anode for the protection of underground metal pipelines is characterized by low density, negative potential, and large protective potential difference with steel. , The protection radius is large, the electricity generated per unit weight is large, and the protected metal is easily polarized, especially suitable for the protection of metals in high resistivity soil and fresh water.
Therefore, when the magnesium alloy sacrificial anode is connected to the underground protected metal by means of cables, etc., the magnesium alloy sacrificial anode and the protected metal form a large battery in the soil medium. At this time, the protected metal body is The cathode, because the potential of the magnesium alloy sacrificial anode is negative than the potential of the protected metal body, is the anode in the protection battery and is consumed by corrosion, so it is called "sacrificial" anode. It can be seen that the magnesium alloy sacrificial anode has a life cycle. With the extension of the service life, the magnesium in the magnesium alloy sacrificial anode continuously loses electrons and is consumed to form magnesium ions. This process is safe.
At the same time, the product of magnesium alloy sacrificial anode is non-toxic, whether it is used in soil or magnesium alloy sacrificial anode used in household electric water heaters, it will not cause harm to soil and human body. It has been reported in the literature that magnesium alloy sacrificial anodes are used in electric water heaters and are also beneficial to human health. In order to reduce the corrosion rate of magnesium alloy sacrificial anode, it is sometimes necessary to provide protection current from an external power supply. The external power supply introduces the protection current into the ground through the buried auxiliary anode, and provides it to the protected metal through the soil. The protected metal is still in the large battery. At the cathode, only the reduction reaction occurs on the surface, and the oxidation reaction of metal ions will not occur again, so that the corrosion is inhibited.
Magnesium is an excellent conductor of heat, and as a physical object, the entire piece must be heated to near the melting point before it can ignite. Usually this does not happen unless the solid magnesium is surrounded by fires from other sources. In this respect, the magnesium alloy sacrificial anode does not need special packaging and protection, and its storage and transportation are convenient.