What are the principles of ceramics?

Thermal radiation
The basic pathways of heat exchange are conduction, convection, and radiation. In order to effectively dissipate heat, people often achieve this by reducing the thermal resistance of the heat flow path and strengthening the convection coefficient, often neglecting thermal radiation. LED lamps generally use Natural convection to dissipate heat. The heat produced by LED is quickly transferred to the surface of the radiator by the radiator. Due to the low convection coefficient, the heat cannot be dissipated into the surrounding air in time, resulting in the rise of the surface temperature and the deterioration of the LED working environment. Increasing the Radiance can effectively take away the heat on the radiator surface in the form of thermal radiation. Generally, aluminum radiators improve the surface Radiance through anodic oxidation. Ceramic materials can have high Radiance characteristics, without complicated subsequent treatment.
Radiation mechanism
The radiation mechanism of ceramic materials is generated by the non resonant effects of random vibrations of two phonons and multiple phonons. High radiation ceramic materials, such as silicon carbide, metal oxide, Boride, etc., all have extremely strong infrared activated polar vibration. Due to the extremely strong anharmonic effect, the absorption coefficient of the dual frequency and frequency region generally has the order of 100-100cm-1, which is equivalent to the lower reflectivity of the residual reflection band in the area of the medium intensity absorption region. Therefore, it is conducive to the formation of a relatively flat strong radiation band.
Generally speaking, radiation bands with high thermal radiation efficiency extend from strong resonant wavelengths to the entire two-phonon combination and frequency region of short waves, including some multi-phonon combination regions. This is a common feature of most radiation bands in high radiation ceramic materials. It can be said that strong radiation bands mainly originate from the two-phonon combination radiation in this band. With a few exceptions, the radiation bands of radiation ceramics are generally concentrated in the two phonon and three phonon regions greater than 5m. Therefore, for infrared radiation ceramics, the radiation in the 1-5m band mainly comes from the intra band transitions of free carriers or direct transitions of electrons from impurity levels to conduction bands, while radiation in the greater than 5m band is mainly attributed to two-phonon combination radiation.