JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II METALLURGICAL THERMODYNAMICS Previous Question Paper (December - 2017 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
Explain the concentration–distance profile for carburization and decarburization of steel.
Answer
In carburization, carbon diffuses from the surface into the steel, creating a concentration gradient that decreases from the surface inward. In decarburization, carbon diffuses from the interior toward the surface, resulting in a concentration profile that increases from the surface toward the bulk material.
Define Marker velocity.
Answer
Marker velocity is the velocity of inert markers placed at the original interface of a diffusion couple, relative to the laboratory frame of reference, which quantifies the shift of the interface due to the unequal diffusion rates of the two species.
The standard free energy of formation of CO from its elements shows negative slope. Why?
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The standard free energy of formation of metal oxides as a function of temperature shows positive slope. Why?
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Define the activity coefficient.
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What is Gibbs – Duhem equation?
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How does the H2O equilibrium phase diagram at low temperature appear?
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Define chemical potential.
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What do the expression Zn / ZnSO4 (aq) ¦ CuSO4 (aq) / Cu represents?
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What is Gibbs – Helmholtz equation?
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PART - B
Explain the variation in potential energy along the path of the diffusion.
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Discuss about Kirkendal effect.
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Discuss the applications based on the second law of diffusion.
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What are Ellingham diagrams? How they are different from constitutional diagrams?
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Explain the advantages and disadvantages of Ellingham diagrams.
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What are Richardson’s diagrams? Explain the derivation and application of Nomographic scale in Richardson’s diagrams.
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Write short notes on: Free energy formation of a binary solution.
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Write short notes on: Sievert’s law.
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Critically discuss on improved integration of the Gibb’s – Duhem equation.
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What is Phase rule? How it is deduced?
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How phase rule is illustrated for one component systems?
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How liquidus and solidus lines for an ideal solution are determined?
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Briefly discuss about reference electrodes.
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Explain the application of Gibb’s – Helmholtz equation to galvanic cells.
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