Study on cermet material for selective absorbing surface

In order to improve the solar thermal performance of selective coating at high temperature, cermet material is used. The material consists of dielectric medium and metal particles, which has excellent optical properties and thermal stability. The coating is deposited by co-sputtering with three metal targets. The structures of the selective surface designed by using numerical modelling calculation. Compared with the existing coating on the vacuum tubes the cermet coating is more stable and has lower emittance at high temperature (350 °C-500 °C). The cermet coating can be used on low concentrate vacuum tube collectors.