Alloy for use in galvanic protection

Abstract

The invention relates to an aluminium alloy and anode made therefrom containing silicon, iron, copper, manganese, magnesium, chromium, zinc and titanium. The anode is used as a sacrificial anode in water vessels with non-metallic hulls.

1 . An alloy which comprises from 0.30 to 0.6 percent silicon plus or minus 5 percent, 0.1 to 0.30 percent iron plus or minus 5 percent, 0.10 copper plus or minus 5 percent, 0.10 percent manganese plus or minus 5 percent, 0.35 to 0.6 percent magnesium plus or minus 5 percent, 0.05 percent chromium plus or minus 5 percent, 0.15 percent zinc plus or minus 5 percent, 0.10 percent titanium plus or minus 5 percent, 0.05 maximum individual trace metals plus or minus 5 percent, 0.15 percent total trace metals plus or minus 5 percent and the balance aluminum. 
     
     
         2 . An anode formed of an alloy according to  claim 1 . 
     
     
         3 . An anode as according to  claim 2 , wherein the electrochemical potential of the anode is more negative than that of the cathode. 
     
     
         4 . An anode as according to  claim 3 , wherein the electrochemical potential of the anode is in the range of −500 to −1200 mV. 
     
     
         5 . An anode as according to  claim 4 , wherein the electrochemical potential of the anode is in the range of −500 to −1200 mV. 
     
     
         6 . An anode as according to  claim 2 , wherein the capacity of the anode to protect the physical integrity of the cathode is in the range of 1000 to 2000 Ah/kg. 
     
     
         7 . An alloy as according to  claim 6 , wherein the capacity of the anode to protect the physical integrity of the cathode is in the range of 1400 to 1700 Ah/kg. 
     
     
         8 . An anode as according to  claim 2 , for use in the galvanic protection of water vessels with non-metallic hulls. 
     
     
         9 . An anode as according to  claim 8 , wherein the vessel is designed for use in seawater. 
     
     
         10 . An anode as according to  claim 2 , wherein the surface area ratio of the anode to the cathode in the electrochemical cell is in the range of 1:1 to 1:20. 
     
     
         11 . An anode as according to  claim 10 , wherein the surface area ration of the anode to the cathode is in the range of 1:2 to 1:20. 
     
     
         12 . An anode as according to  claim 2 , characterised in that an excess negative electrochemical potential is applied across the electrochemical cell.