This set of Ceramics Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Ceramic Defects”.
1. What category does linear defect belongs?
a) 1D defect
b) 0D defect
c) 2D defect
d) 3D defect
View Answer
Explanation: Linear defect belongs to one-dimensional defect around which some atoms are misaligned. Dislocation is an example of linear defects. Point defects belong to 0D defect. Interfacial defects are 2D defects and pores and cracks belong to 3D defect.
2. What is edge dislocation?
a) Shear deformation
b) Extra half plane of atoms
c) Twin boundary formation
d) Stacking fault
View Answer
Explanation: A type of dislocation in which an extra half plane of atoms is introduced in the crystal is called edge dislocation. The line that is defined along the end of the extra half plane of atoms is called dislocation line.
3. What is screw dislocation?
a) Shear deformation
b) Extra half plane of atoms
c) Twin boundary formation
d) Stacking fault
View Answer
Explanation: A dislocation that is formed by a shear stress that is applied to produce distortion is called screw dislocation. The upper front region of the crystal gets shifted one atomic distance relative to the bottom portion along a dislocation line.
4. In edge dislocation, burger vector is ________
a) Parallel to dislocation line
b) Present
c) Perpendicular to dislocation line
d) Not present
View Answer
Explanation: In edge dislocation, burger vector is perpendicular to dislocation line. The nature of dislocation is defined by relative orientations of dislocation line and burger vector. Burger vector is same at all points even though a dislocation changes its direction.
5. In screw dislocation, burger vector is _________
a) Parallel to dislocation line
b) Present
c) Perpendicular to dislocation line
d) Not present
View Answer
Explanation: In screw dislocation, burger vector is parallel to dislocation line. Burger vector will point in a closed packed crystallographic direction and of magnitude equal to interatomic spacing.
6. Burger vector is always measured along close packed plane.
a) True
b) False
View Answer
Explanation: Burger vector is shortest along close packed direction. Stress required for moving dislocation is least in this direction. Therefore, burger vector is always measured along close packed plane.
7. What prevents dislocation movements?
a) Electrons
b) Atoms
c) Grains
d) Grain boundaries
View Answer
Explanation: Two grains having different crystallographic orientation is called grain boundary. Grain boundary has higher energy than grains. They pin the dislocations and movement is prevented by dislocation pile up.
8. How does deformation take place?
a) Dislocation movement
b) Frank reed source
c) Slip between layers
d) Van der Waals forces
View Answer
Explanation: Deformation occurs on slip planes. As stress is applied there is slip along with movement of dislocations. If there is pinning of dislocations, they get regenerated by Frank Reed sources.
9. Schottky and Frenkel defects are example of which defects?
a) 1D defect
b) 0D defect
c) 2D defect
d) 3D defect
View Answer
Explanation: Schottky and Frenkel defects are example of 0D defects. They are also called as point defects. They maintain electroneutrality of the system.
10. What role does point defect play in cubic zirconia?
a) Stabilize the cubic structure
b) Conduction of electricity
c) Diffusion of ions
d) Deformation
View Answer
Explanation: Cubic zirconia is cubic because of presence of point defects that stabilize the cubic structure. We find oxygen interstitials and some dopants in cubic zirconia to help stabilize the structure.
Sanfoundry Global Education & Learning Series – Ceramics Engineering.
To practice all areas of Ceramics Engineering, here is complete set of Multiple Choice Questions and Answers.
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