INTRODUCTION TO SSE

1. INTRODUCTION TO SSE • Solid different with liquid and gas in the way of the arrangement of atom. • Distortion of the crystal is needed to accommodate the solute, unless the two species of solid is very similar.

2. SOLID SOLUTION • Solid solution is when two or more solid mix together in a manner of similar to liquids. • Consider as a solution but not a compound.

3. Factors to form solid solution Hume-Rothery Rules Substitutional Solid Solution Rules • Atomic radii: • Difference in atomic radii between two atoms less about ± 15% 2) Crystal structure: - Crystal structures for metals of both atom types must be same

4. 3) Electronegativity: • Similar electronegativity • More electropositive one element and more electronegative the other, the greater they will form an intermetallic compound 4) Valences: - Higher valency metal have more tendency to dissolve another metal than on of a lower valency

5. INTERSTITIAL SOLID SOLUTION RULES • Solute atoms must be smaller than the pores in the solvent lattice. • The solute and solvent should have similar electronegativity.

6. SUBSTITUTIONAL SOLID SOLUTION • substitutionally, by replacing a solvent particle in the lattice • Solute( compound in minor concentration) or impurity atoms replace or substitute for the host atoms • Species B occupies lattices sites where species A sat. As long as crystal can accommodate B without altering its basic structure, a solid solution occur

8. Example of substitution solid solution is copper an nickel • Two elements completely soluble with each other • The atomic radii for the both are almost the same(15% or less difference.( copper 0.128 while nickel 0.125) • Electronegativities are 1.9 and 1.8 • Same crystal structure • Similar valency

9. INTERSTITIAL SOLID SOLUTION • An interstitial solid solution results when the solute atoms are small enough to fit into the interstices of the metal lattice. • The atoms of the parent or solvent metal are bigger than the atoms of the alloying or solute metal. • the solute atoms occupy the interstitial positions (holes between the atoms) in the crystal lattice of the solute). • The elements that can form interstitial solid solutions with transition metals are hydrogen, carbon, nitrogen and boron.

11. MISCIBLE SOLID SOLUTION • behavior of solid solution where α and β are miscible in all proportions. • show two metals which forms a solid solution at all relative concentrations of the two species. • solid solution can mix when : • i. the species are similar in size. • ii. Chemically similar. • iii. Both form body centre cubic crystal lattices.

12. PARTIALLY MISCIBLE SOLID SOLUTION • shows the phases of a mixture of two substances in varying concentrations. • only limited amount of α will dissolve in β. • the large solid region in between α and β is not solid solution. • It reveal two phase in α+β region. It form separate phase, perhaps lamella or grains.

13. How to Separate a Solid Mixture Solid mixture is a non- homogeneous crystalline structure Each of the solid has different properties : -thermodynamic properties -energy -fugacity

14. How to Separate a Solid Mixture • In order to separate the solid mixture is by using a driving force. -pressure -temperature -energy