Magnesium sacrificial anode has a high open circuit potential and a large output current per unit mass. It is widely used in the protection of steel structures in environments with high resistivity such as oil, natural gas facilities, and deep-sea offshore platforms. According to the open circuit potential, magnesium sacrificial anodes can be divided into high-potential magnesium sacrificial anodes and low-potential magnesium sacrificial anodes. Low-potential magnesium sacrificial anodes are Mg-AI-Zn-Mn alloys, including AZ31, AZ41, and AZ63 magnesium alloys.
Extruding Mg sacrificial anode AZ63
The protection of the inner tank of the water heater needs to be protected by AZ63 magnesium anode, and the length of the sacrificial anode of the inner tank is required to be greater than 300mm. Magnesium sacrificial anodes are mostly produced by metal mold casting, and it is difficult to produce magnesium anodes with a length greater than 300mm. The extrusion process can produce magnesium anode products of unlimited length. The content of AI in AZ63 magnesium alloy is higher, and there are more hard and brittle compounds Mg17A112 distributed in the structure, which leads to the increase of deformation resistance of the alloy and the decrease of plasticity. The extruded magnesium sacrificial anode has a steel core embedded in it. If the steel core and the magnesium anode are not coaxial, it is easy to expose the steel core earlier, resulting in crevice corrosion between the steel core and the magnesium anode, and the current efficiency of the anode is significantly reduced.
After the extruded AZ63 magnesium alloy billet is homogenized and annealed, the Mg17A112 phase is dissolved into the matrix, which improves the deformability of the magnesium anode and helps eliminate extrusion defects.
When extruding AZ63 magnesium alloy, a low extrusion speed should be used, and the die and extrusion cylinder should be well preheated, so that a rod-shaped sacrificial anode with good surface forming and shape error meeting the industry standard can be obtained.
Application of Mg sacrificial anode AZ63
AZ63 magnesium anode has high current efficiency, large power generation per unit mass, stable working potential, uniform consumption, and easy shedding of corrosion products. It is widely used in the protection of buried pipelines, power plant grounding grids, and circulating water pipelines. Moreover, AZ63 magnesium anode can also be used for anti-corrosion protection of ship lock trash rack in fresh water. Aluminum alloy sacrificial anodes are often used for corrosion protection of metal components in aqueous media. However, the resistivity of fresh water is high, and the protection current output by the aluminum anode is small, so it is difficult to play an effective protective role.
