Advanced Powder Metallurgy Processing Techniques
1. ______ gas is used for vacuum atomization process.
A. Argon
B. Nitrogen
C. Helium
D. Hydrogen
Answer:: D
2. Spherical shaped particles are produced by centrifugal atomization.
A. True
B. False
Answer:: A
3. ________ falls under the category of RSP.
A. Centrifugal atomization
B. REP
C. Rotating disk atomization
D. Ultrasonic atomization
Answer:: C
4. _______ process involves the use of rapidly spinning disk for powder production.
A. RSP
B. Ultrasonic atomization
C. Rotating disk atomization
D. REP
Answer:: C
5. Which of the following process can achieve a solidification rate > 1000°C/s?
A. Ultra-rapid solidification process
B. REP
C. Rotating disk atomization
D. Ultrasonic atomization
Answer:: A
6. Which of the following powder production technique involves the use of high-pressure fluid jets?
A. Electrolysis
B. Reduction
C. Atomization
D. Cold stream process
Answer:: C
7. ______ is used in atomization of metals.
A. Hydrogen
B. Compressed air
C. Inert gas
D. Water jet
Answer:: D
8. ________ technique uses high-pressure water jets.
A. Vacuum atomization
B. Water atomization
C. REP process
D. Rotating disk atomization
Answer:: B
9. ________ technique uses high velocity argon, nitrogen or helium gas jets.
A. Centrifugal atomization
B. Gas atomization
C. REP process
D. Rotating disk atomization
Answer:: B
10. Vacuum atomization is also known as _________
A. RSP
B. Ultrasonic atomization
C. Soluble gas atomization
D. REP
Answer:: C
11. REP is also known as _________
A. Centrifugal atomization
B. RSP
C. Rotating disk atomization
D. Ultrasonic atomization
Answer:: A
12. Which of the following is not an advantage of atomization process?
A. Cleanliness
B. Processing capability
C. Reduced versatility
D. Productivity
Answer:: C
13. Atomization process is used for production of metal powders of very high melting point.
A. True
B. False
Answer:: B
14. Which of the following are major components of atomization set-up?
A. Melting, atomization chamber
B. Melting, atomization chamber, dry collection
C. Melting and superheating facility
D. Melting, atomization chamber, collection tank
Answer:: D
15. Complex alloys are melted by ________
A. Vacuum induction melting
B. Vacuum melting
C. Air melting
D. Inert gas melting
Answer:: A
16. The atomization chamber consists of _______
A. Nitrogen
B. Tundish
C. Atomizing atmosphere
D. Atomizing nozzle system
Answer:: D
17. Which gas is used for purging the atomization chamber?
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Helium
Answer:: B
18. _______: where particles solidify before the reach the bottom of the tank.
A. Top collection
B. Wet collection
C. Dry collection
D. Bottom collection
Answer:: C
19. In ________ the collection of powder is done in a water tank.
A. Hydrated collection
B. Wet collection
C. Water collection
D. Dry collection
Answer:: B
20. _______ type of nozzle is used in water atomization.
A. Concentric
B. Free-fall
C. Multiple-jet
D. Annular
Answer:: B
21. ________ type of nozzle design is used frequently in gas atomization.
A. Confined
B. Free-fall
C. Multiple-jet
D. Concentric
Answer:: A
22. ________ gas is produced from fractional distillation of natural gas.
A. Nitrogen
B. Argon
C. Helium
D. Boron
Answer:: C
23. Oil atomization is not suitable for __________
A. bearing steel
B. high speed steel
C. high carbon steel
D. low-carbon steel
Answer:: D
24. __________ is successfully used as an atomizing medium in place of water and gas.
A. air
B. synthetic oil
C. nitrogen
D. argon
Answer:: B
25. The ________ and __________ influence the shape and size of the atomized particles.
A. Cooling conditions, surface energy
B. Cooling conditions, pressure
C. Cooling conditions, surface tension forces
D. Surface tension, volume
Answer:: C
26. Which of the following factors control the average particle size, for a given nozzle design?
A. Pressure of the atomizing medium
B. Reflex angle between the axes of the gas jets
C. Pressure of the atomizing medium, reflex angle between the axes of the gas jets
D. Pressure of the atomizing medium, apex angle between the axes of the gas jets
Answer:: D
27. The results of designs used for free fall atomization are difficult to reproduce by _________
A. True
B. False
Answer:: A
28. Which of the following are the types of nozzles used in atomization process?
A. Annular type
B. Discrete jet
C. Annular and discrete jet type
D. Concentric type
Answer:: C
29. The rate of atomization ______ with increase in temperature.
A. Increases
B. Decreases
C. Zero
D. Constant
Answer:: B
30. What is the effect of increased temperature on the particle size?
A. Independent
B. Decreases
C. Increases
D. Increases first and then decreases
Answer:: C
31. The particle shape of water atomized copper becomes more irregular upon addition of _____
A. Silicon
B. Lithium
C. Tantalum
D. Potassium
Answer:: B
32. The rate of atomization and orifice area have a _______ relation.
A. Logarithmic
B. Inverse
C. Exponential
D. Linear
Answer:: D
33. Which of the following depicts the stages of molten metal disintegration?
A. Wave formation → ligament formation → powder
B. Wave formation → ligament formation → fine droplets → breakdown to smaller particles → powder
C. Wave formation → ligament formation → fine droplets → breakdown to smaller particles → collision & coalescence of particles
D. Wave formation → ligament formation → fine droplets → collision & coalescence of particles
Answer:: C
34. The fraction of coarse powder will increase as the quantity of metal available for atomization increases.
A. True
B. False
View Answer:
Answer:: A
35. Which of the following set of conditions leads to maximum fineness?
A. Increase in air pressure and increase in flow of metal
B. Decrease in air pressure and increase in flow of metal
C. Increase in air pressure and decrease in flow of metal
D. Decrease in air pressure and decrease in flow of metal
Answer:: A
36. The shearing forces involved in atomization depends on the ________
A. Reynolds number
B. Temperature
C. Pressure
D. Biot’s number
Answer:: A
37. Which of the following is a process parameter for atomization process?
A. Orifice volume
B. Pressure of atomizing medium
C. Temperature of atomizing medium
D. Atomizing medium properties
Answer:: B
38. Which force fragments the liquid into ligaments in atomization process?
A. Tensile force
B. Shear force
C. Compressive force
D. Torque
Answer:: B
39. Under which set of conditions is the irregular particle shape obtained?
A. Lower surface tension
B. Lower surface tension and low cooling rates
C. Higher surface tension and low cooling rates
D. Lower surface tension and high cooling rates
Answer:: D
40. Under which set of conditions is the spherical particle shape obtained?
A. Lower surface tension
B. Lower surface tension and low cooling rates
C. Higher surface tension and low cooling rates
D. Lower surface tension and high cooling rates
Answer:: C
41. The particle size decreases with _______
A. increasing surface tension of liquid
B. decreasing velocity of atomizing medium
C. decreasing surface tension of liquid
D. constant velocity of atomizing medium
Answer:: C
42. ______ apex angles lead to fine particles.
A. 89°
B. 0°
C. Lower
D. Higher
Answer:: D
43. ______ is obtained in water atomization compared to gas atomization.
A. Coarse powder
B. Fine powder
C. Ultra coarse powder
D. Spherical powder
Answer:: B
44. Gas atomization results in _______
A. dendritic shape powder
B. irregular shape powder
C. spherical shape powder
D. fine powder
Answer:: C
45. Which of the following factors affect the particle size of atomized powder?
A. Nozzle configuration
B. Atomizing medium and nozzle configuration
C. Properties of metal, atomizing medium and nozzle configuration
D. Atomizing medium
Answer:: C
46. What is the full form of SHS?
A. Standard pressure High-Temperature Synthesis
B. Standard pressure Heat-Temperature Synthesis
C. Self-propagating Heat-Temperature Synthesis
D. Self-propagating High-Temperature Synthesis
Answer:: D
47. In ______, a self-sustaining reaction occurs by local ignition in a reactant mixture.
A. reaction sintering
B. SPS
C. SHS
D. activated sintering
Answer:: C
48. Spontaneous formation of product occurs in SHS.
A. True
B. False
Answer:: A
49. In SHS, _____ are the different classes of reactions recognized.
A. layer-wise combustion mode
B. propagation mode and simultaneous combustion mode
C. volumetric combustion mode
D. propagation mode and layer-wise combustion mode
Answer:: B
50. Conventional combustion processes differ from SHS reactions.
A. True
B. False
Answer:: A
