Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech III POWDER METALLURGY Previous Question Paper (April - 2018 - R15)
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 in Part B carries 10 marks.
Part A
Distinguish between Tap density and Apparent density.
Answer
Apparent density is the mass per unit volume of loose powder poured into a container under specified conditions without vibration. Tap density is the mass per unit volume obtained after the powder container has been subjected to a specified mechanical tapping process to settle the particles and reduce void space.
Distinguish between particle size and particle shape.
Answer
Particle size refers to the linear dimension or diameter of a powder particle, typically measured in micrometers. Particle shape describes the geometric form or morphology of the particle (e.g., spherical, acicular, dendritic, or irregular), which significantly influences the flowability and packing behavior of the powder.
What are the disadvantages of carbonyl decomposition?
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What are the limitations of powder metallurgy?
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Distinguish between solid state sintering and liquid phase sintering.
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Distinguish between Hot isostatic pressing and cold isostatic pressing.
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Why multicomponent alloy powders are produced by Atomisation technique?
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What are the applications of electrical contacts in industries?
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What is heavy alloy and give the applications of these alloys?
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Differentiate between soft magnets and hard magnets with suitable examples.
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Part B
Classify and describe powder particle shapes
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Explain the Sedimentation technique to determine the particle size.
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Discuss the basic thermodynamics, kinetics and practical difficulties involved in production of metal powders by chemical reactions. What are the advantages and disadvantages of this method?
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Describe the following methods and characteristics of the powders produced.
Production of Nickel carbonyl powder by thermal decomposition.
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Production of sponge iron powder by reduction of iron ore.
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Explain the following methods and characteristics of the powders produced
Production of Iron powder by reduction of mill scale.
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Production of metal powders by precipitation from a liquid.
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What is the importance of liquid phase sintering and what are its requirements.
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Describe the stages of liquid phase sintering and explain some actual Liquid phase sintering systems.
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Describe the stages of sintering and discuss the effects of material variables of sintering on products.
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Write explanatory notes on:
Self lubricating bearings (bornzes)
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Tungsten lamp filaments.
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Write short notes on:
Filters
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Tungsten automobile parts.
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Discuss briefly about the following:
Soft magnets
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Cemented carbides.
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Discuss briefly about the following:
Permanent magnets
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Heavy alloys.
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