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What is crystalline defect?

What is crystalline defect?

Crystal defect, imperfection in the regular geometrical arrangement of the atoms in a crystalline solid. These imperfections result from deformation of the solid, rapid cooling from high temperature, or high-energy radiation (X-rays or neutrons) striking the solid.

What is crystal defect PPT?

They are also called intrinsic or thermodynamic defects. Basically , these are of two types ; (i) Vacancy defects (ii) Interstitial defects (i)VACANCY DEFECTS When some of the lattice sites are vacant ,the crystal is said to have vacancy defect. This results in decrease in density of the substance.

What is substitutional defect?

Substitutional Defect occurs when the original atom in the lattice site of a crystalline solid is replaced by a different type of atom. Depending on the size of the substituted foreign atom, the neighboring atoms may remain either in tension or in compression. Substitutional Atom is a Point Defect.

What are volume defects?

Volume defects as name suggests are defects in 3-dimensions. These include pores, cracks, foreign inclusions and other phases. These defects are normally introduced during processing and fabrication steps.

What are two dimensional defects?

The defects are classified into four categories: point defects (PD), topological defects including dislocations and grain boundaries (GB), dislocations in bilayers, and other one-dimensional (1D) defects, ranging from edges, interfaces, to nanowires (NW).

What are the different types of point defects?

There are 3 types of point defects:

  • Stoichiometric defect.
  • Frenkel defect.
  • Schottky defect.

What are the main crystal defects?

There are basic classes of crystal defects:

  • point defects, which are places where an atom is missing or irregularly placed in the lattice structure.
  • linear defects, which are groups of atoms in irregular positions.
  • planar defects, which are interfaces between homogeneous regions of the material.

What are Schottky and Frenkel defects?

In Schottky defect the difference in size between cation and anion is small. Frenkel defect contains ionic crystals where the anion is larger than the cation. Both anion and cation leave the solid crystal. Atoms permanently leave the crystal.

What are the types of point defects?

What are three-dimensional defects?

Bulk defects

  • Three-dimensional macroscopic or bulk defects, such as pores, cracks, or inclusions.
  • Voids — small regions where there are no atoms, and which can be thought of as clusters of vacancies.
  • Impurities can cluster together to form small regions of a different phase. These are often called precipitates.

What are the major classes of point defects?