Question

9.4 Lead sheet is pop-riveted with special bronze fasteners. The total exposed area of the sheet is 100 times that of the fasteners. The environment for the assembly is seawater. Which metal will corrode? If half as many fasteners are used, what influence would this have on the total rate of corrosion? How could corrosion be reduced?

Answer 1

(a) Lead will corrode

(b) fasteners does not have any influence on the rate of corrosion.

(c) The use of protective coating like paint, powder

Step-by-step explanation:

(a) Which metal will corrode: Since bronze is resistant to oxidation, corrosion cannot take place. Lead will corrode due to its reaction with the seawater.

(b) Influence on the total rate of corrosion; No matter the fasteners used, corrosion will still take place as far as the surface of the metal is exposed. therefore fasteners does not have any influence on the rate of corrosion.

(c) there are so many ways to reduce corrosion, some of which includes;

-- The use of protective coating like paint, powder

-- By keeping the surface of the metal dry

-- Not exposing the metal to moisture

---By electroplating it with another metal

Answer 2

Questions are answered in the explanation section.

Step-by-step explanation:

a) Of both metals, lead will corrode, since it reacts with seawater to form oxides, chlorides, etc., while bronze is more resistant to oxidation.

b) The corrosion rate will remain constant, because the concentration of seawater does not change over time, therefore, the corrosion rate is independent of the area that is exposed to seawater.

c) Corrosion can be reduced by using protective coatings, so that the metal is isolated from sea water, for example, paints, acrylic powders, etc.