Quiznetik
Material Science | Set 10
1. which of the following is essential requirement for the galvanic corrosion to occur ?
A. an electrolyte in contact with two metals
B. electrical contact between two metals
C. a difference of potential between two metals
D. all of the above
Correct : D. all of the above
2. which of the following methods are used ot reduce galvanic corrosion ?
A. select two metals that are close together in the galvanic corrosion
B. avoid relatively small area of less noble metal and large area of more noble metal
C. insulate the metal from each other
D. all of the above
Correct : D. all of the above
3. in galvanic corrosion, as the area of anode metal decreases with respect to cathode area of metal, the corrosion rate
A. increases
B. decreases
C. remain constant
D. none of the above
Correct : A. increases
4. pitting corrosion is also known as
A. low temperature corrosion
B. high temperature corrosion
C. bimetal corrosion
D. none of the above
Correct : D. none of the above
5. pitting corrosion is also known as
A. highly localized corrosion
B. low temperature corrosion
C. high temperature corrosion
D. bimetal corrosion
Correct : A. highly localized corrosion
6. pitting corrosion is a bimetal corrosion, the statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
7. galvanic corrosion is a highly localized corrosion, the statement is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : A. false
8. crevice corrosion is also a localized attack, the statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : A. true
9. phenomenon of crevice corrosion is based on
A. electrochemi cal corrosion
B. electromenta l corrosion
C. electromech anical corrosion
D. none of the above
Correct : A. electrochemi cal corrosion
10. crevice corrosion rate become faster due to
A. gases in the liquid or electrolyte
B. high flow of liquid or electrolyte
C. trapped stagnant liquids, which is highly concentrated
D. none of the above
Correct : C. trapped stagnant liquids, which is highly concentrated
11. which of the following remedial measure is suitable to prevent crevice corrosion
A. avoid joining of metal rivets and bolts. use welding
B. avoid solution get into crevice by applying grease
C. routine cleaning must be carried out
D. all of the above
Correct : D. all of the above
12. intergranular corrosion take place at which portion of grain
A. phases in the grain
B. inclusions in the grain
C. grain boundary
D. twin boundary
Correct : C. grain boundary
13. in case of stainless steels, which type of following effect is seen after welding
A. grantization
B. sensitization
C. graphitizatio n
D. none of the above
Correct : B. sensitization
14. which of the following element precipitate on grain boundary, when stainless steel gets sensitized ?
A. vanadium carbide
B. molybdenum carbide
C. tungsten carbide
D. chromium carbide
Correct : D. chromium carbide
15. the chemical formula for chromium carbide which precipitate at grain boundary due to sensitization is
A. cr23c6
B. cr21c5
C. cr20c2
D. cr0c0
Correct : A. cr23c6
16. in case of intergranular corrosion, when grain boundary become ric in chromium then the % of chromium at the depleted region will become
A. lower than 12%
B. more than 12%
C. equal to 12%
D. none of the above
Correct : A. lower than 12%
17. when grain voundary becomes sucseptible to corrosion, due to chromium carbide in stainles steel, this stage of metal is known as
A. graphitizatio n
B. chromitizatio n
C. sensitization
D. none of the above
Correct : C. sensitization
18. one of the following is the preventive measure for intergranular corrosion
A. use of low carbon grade os stainless steel (304l, 316l grade)
B. use of stabilised grade of stainless steel (321 or 322 grade)
C. use post weld heat treatment
D. all of the above
Correct : D. all of the above
19. one of the following step is used to control intergranular corrosion in stainless steel
A. use of metal coatings
B. use of cathodic protection
C. use of anodic protection
D. use of low carbon grade of stainless steel i.e. 304l, 316l
Correct : D. use of low carbon grade of stainless steel i.e. 304l, 316l
20. one of the following step is used to control intergranular corrosion in stainless steel
A. use of metal coating, like electroplatin g
B. use of stabilized grade of stinless steel i.e. (321, 322 grade)
C. use of special type of inhibitor
D. all of the above
Correct : B. use of stabilized grade of stinless steel i.e. (321, 322 grade)
21. what is meant by K.L.A.
A. kinetic low alloy
B. knife low alloy
C. knife line alloy
D. knife line attack
Correct : D. knife line attack
22. knife line attack is which type of corrosion ?
A. bimetal corrosion
B. general corrosion
C. intergranular corrosion
D. all of the above
Correct : C. intergranular corrosion
23. which of the following ia a velocity related corrosion attack?
A. impingement corrosion
B. cavitation corrosion
C. erosion corrosion
D. all of the above
Correct : D. all of the above
24. one of the following is a velocity related corrosion attack in the pipeline
A. general corrosion
B. galvanic corrosion
C. intergranular corrosion
D. none of the above
Correct : D. none of the above
25. one of the following is a velocity related corrosion attack, due to fluid flow
A. impingement corrosion
B. crevice corrosion
C. bimetal corrosion
D. general corrosion
Correct : A. impingement corrosion
26. one of the following is a velocity related corrosion attack, due to fluid flow
A. erosion corrosion
B. galvanic corrosion
C. uniform corrosion
D. none of the above
Correct : A. erosion corrosion
27. one of the following is velocity related attack , due to fluid flow
A. cavitation corrosion
B. uniform corrosion
C. bimetal corrosion
D. intergranular corrosion
Correct : A. cavitation corrosion
28. erosion corrosion can be defined as
A. the precipitation of hard carbides at grain boundary
B. corrosion reaction which accelerated by the relative movement between a corrosive fluid and the metal surface
C. corrosion reaction due to bubbles flowing through the fluid gets burst
D. none of the above
Correct : D. none of the above
29. the rate of erosion corrosion is vary with the velocity of fluid i.e thed velocity of fluid is high. The statement stated is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : B. true
30. out of the following is the measure to control erosion corrosion
A. selection of resistant materials
B. decreasing the flow velocity
C. minimizing turebulence
D. all of the above
Correct : D. all of the above
31. out of the following is the measure to control erosion corrosion
A. decreasing the flow velocity
B. coating the metal surface
C. increasing the temperature of fluid
D. none of the above
Correct : A. decreasing the flow velocity
32. hard particles or asnd particels in a flowing fluid, causes which type of corrosion
A. cavitation corrosion
B. erosion corrosion
C. impingement corrosion
D. none of the above
Correct : C. impingement corrosion
33. the corrosion profile of erosion corrosion shows
A. a smoooth surface profile with directional pattern
B. very rough surface with groves
C. very shiny surface
D. all of the above
Correct : A. a smoooth surface profile with directional pattern
34. one of the following is the remedial measure to control or prevent impingemnet corrosion
A. selection of good resistant metal
B. filtering out the solid particles while entering he system
C. installation of water traps or wear plates and baffles in the path
D. all of the above
Correct : D. all of the above
35. stress corrosion cracking is a combined effect of
A. temperature and time
B. velocity and fluid
C. acidity and stress
D. corrosive environment and mechanical stresses
Correct : D. corrosive environment and mechanical stresses
36. stress corrosion cracking is
A. intergranular cracking
B. transgranular cracking
C. slow cracking
D. none of the above
Correct : A. intergranular cracking
37. hydrogen blistering is happen only because of
A. atomic oxygen that
B. atomic hydrogen
C. atomic nitrogen that
D. none of the
Correct : B. atomic hydrogen
38. corrosion fatigue cracking is a combined effect of
A. strain and corrosion
B. stress and corrosion
C. cyclic stress and corrosion
D. none of the above
Correct : C. cyclic stress and corrosion
39. cracking due to corrosion fatigue is mainly combine effect of
A. temperature and sluid flow
B. fluid velocity and stress
C. stress and corrosion
D. none of the above
Correct : D. none of the above
40. fatigue life of a metal in air is better than fatigue life in sea water. This statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : A. true
41. fatigue fracture is always initiated at
A. discontinuity on the surface
B. dicontinuity in the center of a metal
C. without any discontinity in the metal
D. none of the above
Correct : A. discontinuity on the surface
42. metallic component gets fatigue due to which type of stresses applied
A. tensile stresses
B. compression stresses
C. shear stresses
D. cyclic stresses
Correct : D. cyclic stresses
43. one of the following is a preventive measure to control corrosion fatigue failure
A. eliminate cyclic stresses
B. reduces stress concentratio n
C. obtain a smooth and shiny surface on the metal
D. all of the above
Correct : D. all of the above
44. high temperature corrosion of a carbon stee; can be a problem at a temperature above
A. 500 oc
B. 1000 oc
C. 1500 oc
D. none of the above
Correct : A. 500 oc
45. the best example of high temperature corrosion is
A. creep failure
B. oxidation
C. high temperature hydrogen attack
D. all of the above
Correct : D. all of the above
46. the rate of corrosion increases as the temperature ncreases. The statement given is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : B. true
47. one of the following methods is not a corrosion prevention method
A. internal and external coating
B. corrosion inhibitor
C. cathodic and anodic protection
D. all of the above
Correct : D. all of the above
48. one of the following methods is not a corrosion prevention method
A. use of special alloys
B. removal of corrosive gases
C. dehydration
D. all of the above
Correct : D. all of the above
49. non metalic coatings are more durable than metallic coatings. The given statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
50. metaliic coatings gives best protection against corrosion over metallic coating. The statement is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : B. true
51. non metallic coating gives best protection against corrosion over metallic coating. The statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
52. metalic coatings are more durable than nonmetalic coatings. This statement is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : B. true
53. one of following method is a metallic coating method for protection from corrosion
A. metal spraying
B. electroplatin g
C. metal cladding
D. all of the above
Correct : D. all of the above
54. in hot dipping process, liquid metal of zinc is never used in any case. This statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
55. in hot dipping method of metal coating, which metal is coated on the steel to protect from corrosion ?
A. silver
B. aluminium
C. chromium
D. zinc
Correct : D. zinc
56. in hot dipping method of metal coating, which one of the following metal is used ?
A. copper
B. silver
C. aluminium
D. none of the above
Correct : D. none of the above
57. in electroplating process for a metal coating, the metallic component on which coating is
A. anode
B. cathode
C. electrolyte solution
D. none of the above
Correct : B. cathode
58. in electroplating process for metal coating, the metallic component on which coating is needed, is made anode in the process. This statement is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : A. false
59. one of the following is a metal used for metallic coatings, used fro protection from corrosion
A. chromate coating
B. phosphate coating
C. plastic coating
D. all of the above
Correct : D. all of the above
60. one of the following is a non-metallic coatings, used for protection from corrosion
A. chromate coating
B. phosphate coating
C. plastic coating
D. all of the above
Correct : D. all of the above
61. corrosion inhibitors are used to protect the metal from corrosion. This statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : A. true
62. corrosion inhibitors are applied on the metal by electroplating process. Te statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
63. corrosion inhibitors are the chemicals that react with the metal surface, gets absorb and form a thin film on metal . This statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : A. true
64. one of the following is the main application of corrosion inhibitors
A. power plant
B. engine coolin g system
C. pipeline carrying hydrocarbon s
D. none of the above
Correct : D. none of the above
65. the corrosion inhibitor work by one of following mechanisms
A. they form precipitate and coat the metal
B. they combine with corrosion product films
C. they absorb on metal surface
D. all of the above
Correct : D. all of the above
66. one of the following is inhibitor which is used in metal protection.
A. zinc
B. aluminium
C. copper
D. none of the above
Correct : D. none of the above
67. in cathodic protection, it protects the metal by coating it with a suitable method. This statement is --
A. true
B. false
C. not applicable to it
D. none of the above
Correct : B. false
68. one of the following processes is a cathodic protection method.
A. hot dipping
B. electroplatin g
C. impresssed current
D. phosphating
Correct : C. impresssed current
69. one of the following processes is a cathodic protection method.
A. metal cladding
B. metal spraying
C. hot dipping
D. none of the above
Correct : D. none of the above
70. one of the following processes is a cathodic protection method.
A. metal spraying
B. electroplatin g
C. metal cladding
D. sacrificial anode
Correct : D. sacrificial anode
71. one of the following is a main advantage of sacrificial anode method
A. external power supply is not required
B. minimum maintenance
C. very easy to operate
D. all of the above
Correct : D. all of the above
72. one of the following is the main advantage of impressed current method
A. applicable to large objects
B. uncoated parts can be protect
C. can protect underground steel structure
D. all of the above
Correct : D. all of the above
73. anodes are dissolving in case of sacrificial anode method which is one of the cathodic protectionmethod. This statement is
A. true
B. false
C. not applicable to it
D. none of the above
Correct : A. true
74. anodes are dissolving in case of impressed current method, which is one of the cathodic protection method. This statement is
A. false
B. true
C. not applicable to it
D. none of the above
Correct : A. false
75. one of the following is a corrosion resistance alloy
A. stainless steel
B. nickel base alloys
C. cobalt base alloys
D. all of the above
Correct : D. all of the above
76. one of the following is a corrosive gas, which corrode the metal very fast
A. o2
B. co2
C. h2s
D. all of the above
Correct : D. all of the above
77. dehydration means removal of water from the system, to control corrosion . This
A. true
B. false
C. not applicable to
D. none of the above
Correct : A. true
78. dehydration is nothing but
A. removal of metal
B. removal of water
C. removal of matter
D. none of the above
Correct : B. removal of water
79. one of the following corrosive gas, possess a highest corrosion rate, withrespect to carbon steels ?
A. co2
B. o2
C. h2s
D. h2
Correct : B. o2
80. one of the following corrosive gas, possess a lowest corrosion rat, with respect to carbon steels, than any other gases?
A. co2
B. o2
C. h2s
D. h2
Correct : C. h2s