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Code No: 37111 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD IV.B.TECH - I SEMESTER REGULAR EXAMINATIONS NOV/DEC, 2009 ELECTRO METALLURGY AND CORROSION (M M T) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --1. a) Explain the Faradays law’s of electrolysis. b) Distinguish fully among, electrolylite, anode, cathode and electrolysis. [8+8]

Name the various measuring instruments used in electrochemistry and explain about them in detail. [16]

3. a) b)

Explain various factors that affect current efficiency & energy efficiency. What’s specific conductivity? What is its significance? Explain how it can be measured. [8+8]

4

Write a detailed note on the electro winning of Cu & Zinc.

5.

Write any essay on the various thickness tests and hardness tests that are performed on the various types of electrodeposits. [16]

6. a) b)

Discuss the various factors that can cause increased rate of corrosion in galvanic cell. Compare and contrast erosion corrosion and frettling corrosion. [8+8]

7.

List out various corrosion protection methods. Explain all of them in detail.

8.

Explain the various cathodic and anodic protection methods against corrosion.[16]

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2.

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****

[16]

[16]

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Code No: 37111 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD IV.B.TECH - I SEMESTER REGULAR EXAMINATIONS NOV/DEC, 2009 ELECTRO METALLURGY AND CORROSION (M M T) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks ---

Define and explain the term electrolysis. Explain the mechanism of electrolysis. What is electrolytic conduction? Discuss the importance of electrolytic conductance for a metallurgist in process industries. [8+8]

2. a) b)

Write a detailed notes on ‘electrophoresis’ What is meant by exchange current densities? How it can be measured? Discuss. [8+8]

3. a)

Explain the differences between soluble electrodes and insoluble electrodes with suitable example. What are anode and cathodes. What are their important functions. Explain about soluble and insoluble anodes & cathodes in the examples. [8+8]

b)

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1. a) b)

Explain the various types of electrolytic baths used for the electro mining of Cu & zinc. What is Co-deposition? Explain the principles involved in the co depositions of metals. [10+6]

5. a) b)

Explain the effect of polarization on electro deposition. Explain with suitable examples: i) Electro winning ii) Electro refining and iii) Electro deposition. Explain the following types of corrosion. Crevice corrosion. Pitting corrosion Stress corrosion cracking.

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6.

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4. a) b)

a) b) c)

8. a) b)

[5+5+6]

What do you mean by inhibiters? What are the various types of inhibiters. Explain the various types of inhibiters and explain about any 4 of them. [16]

Aj

7.

[8+8]

Explain the effect of (i) galvanic coupling and solution concentration on corrosion rate. Explain how the corrosion may be minimized. [10+6] ****

SET-3

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Code No: 37111 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD IV.B.TECH - I SEMESTER REGULAR EXAMINATIONS NOV/DEC, 2009 ELECTRO METALLURGY AND CORROSION (M M T) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --1. a) Explain the various factors that affect electrolytic conduction. b) Explain the following: i) Electrode potential of metals. ii) Reference electrodes. [8+8]

What do you mean electrochemistry? Discuss it is detail. Name a few measuring instruments which are used in electrochemistry and explain their working principle in detail. [16]

3. a) b)

Discuss about EMF series and galvanic series. Explain the following. i) Throwing power ii) Standard and equilibrium potential

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2.

[8+8]

Explain the effect of current diversity on electro deposition characteristics. Discuss the recovery of Zinc from its aqueous solutions by electro winning process. [8+8]

5. a) b)

Explain the various factors that affect the structures of electro deposits. Write a short notes on electro plating of chromium giving the anode, cathode, electrolyte, both composition and other details. [8+8]

6. a) b)

Explain the beneficial effects of galvanic corrosion. Explain the following. i) Dezincification. ii) intergranular corrosion.

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4. a) b)

7. a)

What are the various factors that are to be considered, on the selection of machines to protect a material against corrosion. Explain about various metallic coating methods for corrosion protection. [8+8]

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b)

8. a) b)

[8+8]

Explain the advantages of metallic coatings over non-metallic coatings. Write a short note on surface protection methods for corrosion prevention. [8+8] ****

SET-4

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Code No: 37111 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD IV.B.TECH - I SEMESTER REGULAR EXAMINATIONS NOV/DEC, 2009 ELECTRO METALLURGY AND CORROSION (M M T) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --1. a) Distinguish between electrolytic conductors and metallic conductors. b) Explain the importance of pour baix diagram in aqueous electrometallurgical processes. [8+8] 2. Discuss various methods, equipment used for testing of electro deposits. [16]

Explain the differences between soluble electrodes with suitable examples. What do you mean by a reference electrode? What are its functions? Explain the working principles of reference electrodes with suitable examples. [8+8]

4.

Write short notes on the following: a) Current efficiency b) Energy efficiency c) Throwing power.

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3. a) b)

[16]

Discuss the factors that affect the efficiency of electrodes. Compare and contrast ‘electro mining’ and electro refining with necessary examples [8+8]

6. a) b) c)

Explain how corrosion behaviour can be predicted. Explain the mechanism of electrochemical corrosion. Explain why corrosion generally occur at anode.

7. a) b)

Explain in detail about ‘corrosion protection’ & corrosion control. Explain about the following surface protection methods. i) Painting and ii) Metallic coating.

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5. a) b)

Explain about various methods of cathodic protection. Write short notes on sacrificial anode. Explain the nature of protection given to steels by ‘zinc coating’

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8. a) b) c)

****

[8+5+3]

[8+8]

[8+4+4]