thermal properties

2-1 INTRODUCTION:
Heat is essentially the vibration of atoms in a material. Consequently thermal properties reflect the type and strength of interatomic bonding and the crystal structure. The important thermal properties of any material are
- Heat capacity
- Coefficient of thermal expansion
- Thermal conductivity
Thermal properties of ceramics differ from those of metals whenever free (conduction) electrons are involved, such as in thermal conductivity. However, heat transfer by phonon (lattice vibration) transport can in some cases be more effective than through the movement of electrons. Table 2.1 lists the important parameters used in this chapter and their units. The SI unit of temperature is Kelvin (K), but as you will have realized by now °C is often used in presenting data in materials science.
2-2 ABSORPTION AND HEAT CAPACITY
When a solid absorbs an amount of heat, dq, its internal energy, E, rises by an amount dE where
dE = dq (2.1)
The increase in internal energy is largely due to the increased vibrational amplitude of the atoms about their equilibrium positions. This vibrational motion represents the thermal energy of the solid. There are other mechanisms for heat absorption, but these are either negligible or absent entirely.