Chap2 Material and Structure
Chap2 Material and Structure
2.1.Materials classification Materials can be classified according to: √The type of bonding The structure(crystalline or amorphous) √The properties √The application
Materials can be classified according to: The type of bonding The structure(crystalline or amorphous) The properties The application 2. 1. Materials classification
Type of bonding lonic bonding Primary covalent bonding Metallic bonding Van der walls Secondary Hydrogen bonding
Type of bonding Primary Ionic bonding covalent bonding Metallic bonding Secondary Van der walls Hydrogen bonding
(1)Primary Bonding- (a)IONIC BONDING Between metallic(M)and non metallic (X)elements: Metals gives up an electron to non metallic element M+and X ions are formed A Coulombic attraction is created The bonding is non-directional Mostly "diffused"among ceramic materials Typical example: Sodium chloride Na
(1) Primary Bonding- (a)IONIC BONDING Between metallic(M) and non metallic (X) elements: Metals gives up an electron to non metallic element M+ and Xions are formed A Coulombic attraction is created The bonding is non-directional Mostly “diffused” among ceramic materials Typical example: Sodium chloride
COVALENT BONDING Electrons are shared between atoms or molecules in order to saturate the valence. The simplest examples is the H,molecule,where electrons stay longer between the two nucleii rather than in the outer areas->the bonding takes place H C=C HH H H H H HHH HH HH Diamond(ceramic) monomer
(b)COVALENT BONDING Electrons are shared between atoms or molecules in order to saturate the valence. The simplest examples is the H2 molecule, where electrons stay longer between the two nucleii rather than in the outer areas→the bonding takes place Diamond(ceramic) ethylene Poly-ethylene (polymer) monomer