Material Science - Oxidation and Corrosion

1. Which one is the wrong anode-cathode combination

(a) Zinc-Iron

(b) Nickel-Titanium

(c) Iron-Tin

(d) Silver-zinc

2. The metals which do not form adherent oxide film on surface are

(a) Gold and Silver

(b) Iron and Steel

(c) Copper and Aluminium

(d) Nickel and Titanium

3. Which of the following elements added to iron to improve its oxidation resistance

(a) Zinc

(b) Magnesium

(c) Chromium and aluminium

(d) None of the above

4. The corrosion by the mechanism of oxygen absorption can occur if

(a) Electrolyte is neutral or alkaline

(b) Electrolyte is neutral or acidic

(c) Electrolyte is neither neutral and nor acidic

(d) None of the above

5. In order to form a protective oxide layer, the ratio of the volume of oxide formed to that of metal consumed should be

(a) greater than one

(b) less than one

(c) much greater than one

(d) none of the above

6. The potential of a galvanic cell of copper (potential of +0.34 Volt) and aluminium (potential of –1.66 Volt) is

(a) +1.5 Volt

(b) +1.66 Volt

(c) –1.32 V

(d) +2 Volt

7. In the corrosion process by evolution of hydrogen

(a) the cathodes have larger area than anodes

(b) the anodes have larger area than cathodes

(c) the areas of anodes and cathodes are same

(d) none of the above

8. The highest percentage of chromium that can be added to steel is usually

(a) 25

(b) 18

(c) 15

(d) 10

9. Carbon percentage in cutley steel is

(a) 1.35 to 1.65

(b) 0.76 to 0.80

(c) 0.25 to 0.30

(d) 0.5 to 1.0

10. The stainless steels owe their resistance to the presence of

(a) Carbon

(b) Sulphur

(c) Manganese

(d) Chromium


Answers

    1. (d)    2. (a)    3. (c)    4. (a)    5. (a)

    6. (d)    7. (b)    8. (b)    9. (c)    10. (d)

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