Sacrificial anodes are a method of protecting structures from corrosion by outputting current to polarize the potential of the protected structure to a certain extent. Different materials have varying self-corrosion potentials, so their required protection potentials also differ. To meet the needs of various protected structures, a series of sacrificial anodes with different potentials have been developed.
Sacrificial anode materials mainly include magnesium alloy sacrificial anodes, zinc alloy sacrificial anodes, and aluminum alloy sacrificial anodes. These anodes are suitable for different environments based on their performance characteristics. Magnesium anodes are primarily used in high-resistance environments such as soil and freshwater, while zinc alloy sacrificial anodes and aluminum alloy sacrificial anodes are mainly used in low-resistance environments like seawater. Among them, aluminum anodes are widely used for corrosion protection of metal components in marine environments due to their lightweight and high electrical capacity.
Conventional Marine Environment
In marine environments, sacrificial anode technology is relatively mature. The basic composition of commonly used sacrificial anode materials has been largely standardized. These include zinc alloy sacrificial anodes, conventional aluminum alloy sacrificial anodes, aluminum alloy sacrificial anodes, sacrificial anodes for special environments, deep-sea sacrificial anodes, and high-strength steel * low driving potential sacrificial anodes.
Alternating Wet and Dry Environments
In marine tidal zones or the superstructures of submarines, the environment alternates between wet and dry conditions. In such environments, the corrosion products generated by sacrificial anodes during immersion cannot detach from the surface in time, leading to crust formation on the anode surface. This prevents the anode from activating effectively and causes premature failure. To address this issue, an AI-Zn-In-Mg-Ga-Mn high-activation sacrificial anode material has been developed. This material exhibits excellent electrochemical performance in alternating wet and dry environments, with a negative and stable working potential, and its corrosion products are easily shed. It has already been applied in ships.