Breviary Technical Ceramics






5.4 Thermal Properties

5.4.1 Thermal conductivity

The thermal conductivity [Wm^-1 K^-1] of ceramics is generally less than that of metals such as steel or copper. Materials such as silicon carbide or aluminium nitride however, find applications as heat conductors, due to their relatively high thermal conductivity compared with other electrically insulating materials.
Other ceramic materials, in contrast, are used for thermal insulation due to their low thermal conductivity. These insulating properties can be enhanced by inducing porosity in the ceramic. Ceramic fibre matting has a similar effect.
When comparing the thermal conductivity of different materials, it is important to note the temperature range, e.g. 30-100 for figures relevant to the range from 30 to 100 °C.

Test procedures for determining thermal diffusivity (a), which is related to thermal conductivity as ?= a·?·cp, are specified in DIN EN 821-2.

Figure 90: A guide to the flexural strength and thermal conductivity of selected materials

Figure 91: A guide to the coefficient of thermal expansion and thermal conductivity of selected materials


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