Question

1. Point defects- such as vacancies and interstitials – are examples of crystalline defects. Why are
they called “crystalline”? Are there no vacancies and interstitials in non- crystalline solids? Justify
your answer. 

2. How do grain boundaries influence the chemical; and mechanical properties of a metal? 
(must mention about the corrosion properties)

3. How would you expect the diffusion process to change if the slide was changed from amorphous
to crystalline glass?  

Answer 1

Question 1.

In crystalline solids there is uniformity of structure and arrangement of atoms.

Some time this uniformity distrub interms of defects.

Defects are point , line and surface types.

In crystalline solids there is well defined distances between the atoms.

But in non crystalline solids there is a lack of large range order. So point defects are not formed in non crystalline solids.

Question 2.

Grain boundary is the interference between two grains. The grain size and grain boundary are interrelated.

And the properties of metals are realted to grain boundary.

The mechanical properties decreases with increasing grain boundaries and decreasing grain size.This leads to more loss of surface abrasive leads to corrosion.

In chemical point of high density of grain boundaries increases the reactivity of surface through electron activity and diffusion it effects the corrosion.

Question 3.

Diffusion process is the motion of one atom realtive to another atom

Generally glass is non crystalline solid. When temperature changes it influences the relative motion of atoms which leads increasing in diffusion process though slides.

When the temperature decrease the diffusion rate decrease and atoms realtive motion slows down. It causes proper arrangements and definite range of distance between the atoms.

So diffusion process influences the non crystalline phase and crystalline phase.