Crystal Defects or Imperfections

CRYSTAL DEFECTS OR IMPERFECTIONS

1. Introduction

✓ Upto now, we have described only ideal crystals. An ideal crystal is one that contains no lattice defects. However, ideal crystals neither occur in nature nor can be produced by artificial methods. Thus real crystals are never perfect.

✓ The imperfections or defects are always present in actual crystals and their effects are often very important in under- standing the properties of crystals. This is because many impor- tant properties of materials such as mechanical strength, ducti- lity, crystal growth, magnetic hysteresis, dielectric strength, etc., are greatly affected by the presence of defects in crystals. 

✓ Purpose of the study of imperfections in crystals: The two main reasons for the study are as follows:

1. It provides a good understanding of crystals and how they affect the properties of metals.

2. It helps in finding the possibilities of reducing or removing these defects.

Note 

The term defect or imperfection is generally used to describe any deviation from the perfect periodic repeated array of atom in the crystal.