Table 1 Measured potentials relative to a reference for meta

Table 1 Measured potentials, relative to a reference, for metals in soil Metal Potential in soil (V) 1.05 +0.30 Aluminium alloy Graphite Cast iron 0.50 0.20 0.20 Copper Brass Lead Magnesium alloy Mild steel 0.50 1.60 0.65 1.10 Zinc a. Construct a galvanic series for metals in soil. (The most negative potentials should be at the bottom of the table, and the most positive at the top.) b. Compare the series you obtained in Part (a) with the galvanic series for metals irn seawater, given in Block 5 Part 1. What consequences do the two series have for materials selection for components that will be in contact with seawater or buried in soil? c. Determine the potential difference between brass and mild steel in soil and state which one will corrode

Solution

Answer-(a)- Galvanic series for metals in soil

1-Graphite

2-Copper

3-Brass

4-Lead

5-Cast Iron

6-Mild Steel

7-Aluminium alloy

8-Zinc

9-Magnesium alloy

Answer-(b)- Galvanic series in seawater is reverse of Galvanic series in soil.If a material is in top of Galvanic series in seawater then that will be in bottom of Galvanic series in soil means if a material is best in sea water then that will be wrost in soil.

Answer-(c)- potential difference between brass and mild steel = (-0.20)-(0.65) =0.45V

Mild steel will corrode.