High-performance WZr-SiZrO cermet-based solar selective coatings: Enhanced thermal stability and oxidation resistance

Abstract

Cermet-based solar selective absorbing coatings (SSACs) are critical for solar photothermal energy conversion, as their optical properties and thermal stability directly govern the efficiency and lifetime of power generation systems. However, under extreme conditions such as high temperatures (>550 °C) and oxidative or low-vacuum environments, conventional cermet-based SSACs face two key challenges: on the one hand, inward oxygen diffusion alters the coating's composition and microstructure; and on the other, metal nanoparticles within the cermet layer aggregate and coarsen, degrading the optical performance. To overcome these limitations, this study employs SiZrO as an advanced anti-reflective and oxygen-diffusion barrier layer, as well as a synergistic approach combining modified amorphous ceramic networks and microalloying to enhance cermet thermal stability. The resulting WZr-SiZrO-based SSACs demonstrate outstanding optical performance (α = 96.1 %, ε = 15.5 %@500 °C) even after annealing at 650 °C for 1050 h under 0.2 Pa. Additionally, accelerated aging tests indicate that the coating's service lifetime can exceed 25 years at 620 °C/0.2 Pa. With its high efficiency, exceptional durability, and scalable fabrication, this coating is a promising candidate used in the next-generation concentrated solar power (CSP) technologies.