Study On High Potential Sacrificial Anode Material Based On Magnesium

The sacrificial anode materials are functional materials with special electrochemical performances that are widely used in corrosion prevention engineering.At present,three kinds of sacrificial anod materials commonly used b are based on zinc , magnesium and aluminium.The Al-based anode with low density,high current efficiency, much power generated, moderate potential, is a rapidly developed new sacrificial anode material. Zn-based anode with high density, less power generated, low potential, ease to polarize at high temperature, is usually used in the environment of low electrical resistance. Mg-based anode with high potential , is used in soil environment of high electrical resistance, its application is increasing because of the unique electrochemical properties and the protective effect.Currently, the world market demand for magnesium alloy sacrificial anodes of 3-4 million tonnes a year,and its growth rate is 20% yearly.However, current efficiency of the commodity magnesium sacrificial anode is not very high, life is short.Therefore, it is important to develop some new high potential magnesium sacrificial anode with good electrochemical performance. In this thesis, the influences of alloy element Ca and heat treatment technology on microstructure and electrochemistry property of magnesium-manganese sacrificial anode are systemically studied by using optical microstructure (OM), x-ray diffraction(XRD),scan electric microscopy (SEM)/energy dispersive spectrometer (EDS), PGSTAT30 electrochemical measurement system.The results of alloy element Ca addition show that: the microstructure of magnesium-manganese alloy are refined, the electrochemical performance of magnesium-manganese alloy are changed. The corrosion potential of magnesium-manganese alloy with the addition 0.6% Ca declines about 70mV,and the corrosion rate of magnesium-manganese alloy decreases to 35%. The corrosion potential of magnesium-manganese alloy with the addition 0.6% Ca is 60mV less than a commodity magnesium sacrificial anode, the corrosion rate is 40% less than a commodity magnesium sacrificial anode.The results of heat treatment show that: the electrochemical performance of magnesium-manganese alloy are affected by solution treatment temperature and time. After solution treatment the corrosion potential of magnesium-manganese alloy with the addition 0.6% Ca improves about 15mV, the corrosion rate of magnesium-manganese alloy declines about 25%. Its corrosion potential is 50mV less than a commodity magnesium sacrificial anode,and its corrosion rate is 60% less than a commodity magnesium sacrificial anode.In general, the magnesium-manganese alloy with the addition 0.6% Ca is a new high potential magnesium sacrificial anode with good electrochemical performance.