# Diploma courses

### Structure - Property Relations in Materials

#### Course Description

Introduction. Crystal systems and crystal lattices. Miller indices. Simple geometric calculations of properties (e.g. density) based on crystalline structure. Types of bonds and interactions in crystals. Lattice energy and its calculation. Madelung constant. Defects (point, line, surface, volume). Dislocations and their role in plastic deformation. Diffusion in the solid state. Transition state theory for estimating elementary jump rate constants. Random walk model of diffusive transport. Estimation of the diffusivity from atomic-level characteristics. Solution of the diffusion equation under steady-state and transient conditions, for various characteristic geometries. Vibrational modes of a crystal lattice. Einstein and Debye theories of the heat capacity of solids. Density of vibrational states, Debye temperature, low temperature limit of the heat capacity. Thermal expansion of solids. First and second-order phase transitions. Melting, Lindemann criterion. Electrons in a metal as an ideal Fermi gas. Density of electronic states, Fermi energy. Electronic contribution to the heat capacity of metals. Thermal conductivity of non-metallic materials. Thermal conductivity of metals. Conduction of electricity in metals. Relation between thermal and electrical conductivity in metals: Wiedemann-Franz law. Electronic band theory. Nearly free electron model. Conductors, insulators, semiconductors (intrinsic, extrinsic). Hall effect and measurement of the density of carriers. Dielectric properties of solids. Relating the dielectric constant and the index of refraction to the molecular polarizability and dipole moment. Dielectric relaxation and principles of dielectric spectroscopy. Mechanical properties of solids. Basic principles of elasticity theory, elastic constants. Plasticity, creep. Fracture mechanisms. Hardness measurements. Mechanical properties of thin films.

7th Semester - Direction "Material Science"

**Teachers:** Th. Theodorou, C. Charitidis, G. Papadopoulos

http://mycourses.ntua.gr/courses/CHEM1006/

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