The Brayton cycle-based tower solar thermal power system features a flexible layout and operates at high receiver temperatures. However, fluctuations in solar irradiance can lead to thermal fatigue of receiver materials or excessive surface temperatures, necessitating effective strategies to mitigate temperature fluctuations. This study develops a manganese-based thermochemical thermal protection coating utilizing a reversible redox reaction. When solar radiation intensifies and the temperature exceeds 978 ℃, the coating undergoes a reduction endothermic reaction, reducing the heating rate. Conversely, when solar radiation decreases and the temperature drops below 878 ℃, an oxidation exothermic reaction occurs, slowing the cooling rate, thereby stabilizing receiver surface temperature fluctuations. Experimental results indicate that when the mass ratio of the coating material to the binder is 4:3, the adhesion strength reaches the highest national standard level, and the solar weighed average absorptivity achieves 94.93%. After undergoing 500 hours of thermal aging at 950 ℃, 100 cycles of thermal cycling, and 200 cycles of redox reaction tests, the coating’s weighed average absorptivity decreased by only 0.82, 0.98, and 2.61 percentage points, respectively, while maintaining the highest adhesion strength. Under a sudden change in concentrated solar radiation flux of ±9.7 kW/m², the heating and cooling rates in the first 100 seconds were reduced by 59.66% and 67.09%, respectively. Additionally, the time required for a 20 ℃ increase and decrease was extended by 182.50% and 438.60%, respectively. The manganese-based thermochemical coating demonstrates excellent aging resistance and effectively suppresses absorber temperature fluctuations, making it highly promising for applications in Brayton cycle-based tower solar thermal power systems.

thermochemical material  /  coating  /  solar receiver  /  thermal protection