A High‐Emissivity Coating Comprising Chromium–Aluminum Phosphate for Thermal Protection at High Temperatures

ABSTRACT High‐emission coatings are the focus of significant attention for their efficient thermal protection in aerospace applications. Aluminum–chromium phosphate solution (ACP) was synthesized in this study by utilizing H 3 PO 4 , Al(OH) 3 , CrO 3, and CH 3 OH as raw materials. Subsequently, a room‐temperature curing high‐emissivity coating was effectively developed by employing ACP as the binder, Mg‐MOF‐74 as the curing agent, SiC and ZrB 2 as radiating agents, and Al 2 O 3 and ZrO 2 as high‐temperature stabilizers. Consequently, the coating exhibited exceptional thermal stability and radiation performance, with a mass residue rate of 98.71% after exposure to 1500°C. And the emissivity exceeded 0.93 at room temperature and measured ε (3–8 µm) = 0.84 and ε (8–18 µm) = 0.9 after treatment at 1200°C. Thus, the coating developed in this study provides durable and highly effective thermal protection under high‐temperature conditions.