University:
York University
Course:
CHEM 1100 | Chemistry and Materials Science for Engineers
Academic year:

2021
Views:

488

Pages:

2
Author:

Nick T.

Every crystal have defects sometimes Good Sometimes Bad imprefection mostly its blc its electricity always bad when it comes to electrical properties tied to e (trap them) S production at times. result in lack of Do we want defects? Depends properties S how it influence on them. FACTS Defects contribute. or bad. to knowing I justifying if a material is good Define properties of a material? 4 Defects bonding ( type of bonding) 4 Structure (crystalline or Amorphous) to be Changed properties will change if they are Composition elements you choose for bonding how we choose to bond Aloms it depending on what you Choose will define which will later the Structure 3 bonding type introduce defects of microstructure. result in manipulation small scale Structure of a material. Imprefections in bolids loose bands blw atoms Solidification liquid to solid transition. Atoms are further away = Defect. nucle crystals liquid growing grain structure to end up with a solid material made of various Crystals. inside each of those grains Different orientation of atoms. Beginning cooling molten material nuclei Start forming in liquid. After that with time Crystals form slowly Still there is remaining molten materials. too. FACT: there is no such thing as a 3 many important properties are perfect crystal. caused by these imprefections. Types of imprefections : (an atom) Point Defects. Dimension of defect. '00' vacancy atoms (missing atom) Intersitial atoms. Squeezed to positions where ( they are not supposed to be) atoms Substitutional (comes in place of other atoms) Line Defects 10' '20' Dislocations Defect in a line Area Defects. ог volume '3D' Area = planar Defect Grain boundaries pores volume sponge for an ex to fill the space distortion of planes Inwards FACT Vacancy distortion of planes Outwards to make space Intersitial atom Self if same atom of same element is Squeezed there : mobility of atom / Diffusion happens bic of temp change