Wednesday, 7 August 2013

8/08/13 Week 5 Thursday 2013 Period 2

Background Research - Surface area's affect on galvanic corrosion
When dealing with surface area as a variable in galvanic corrosion the area ratio of the anode:cathode is an important variable that affects the corrosion rate pertaining to the anode. This area ratio is also important when cosidering the amount of current available that arises from the cathodic reation.
 
The image below taken from the Corrosion-Club.com demonstrates the affect surface area has on galvanic corrosion:
The diagram suggests that the lower the ratio of anode:cathode the higher the corrosion rate at the anode is likely to occur. When the same situation's ratio is flipped the higher the ratio of anode:cathode results in little influence to help corrode.  If the cathode is larger than the anode, this allows for more oxygen reduction and other cathodi reaction which as whole results in a greater galvanic current. t would beinteresting to find imformation on what results would occur if the ratio was 1:1.
 
When putting this information into the context of tin can corrosion the Fe is considered the anode as it is the metal oxidising. Therefore is the ratio of Sn is higher than Fe then the corrosion rate should increase. This information presented here assists in proving the validity of the hypothesis made in the first post.
 
Link to valuable resource:
 
 

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