Thermal conductivity is one of the basic thermophysical properties which determines the heat flux and the temperature field in a material for unit spatial configurations and boundary conditions. Thermal conductivity is the quantity of heat transmitted, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area, when the heat transfer is dependent only on the temperature gradient. In practice, thermal conductivity is measured as: K = Heat Flux / Thermal Gradient K is defined as a phenomenological constant: K = a. d. Cp where:-a - thermal diffusivity , d - density, Cp - heat capacity. | 
