Effect of Growth Condition on Mechanical Properties of Zirconium Carbonitride Absorber-Based Spectrally Selective Coatings

Abstract

Zirconium carbonitride (ZrC-ZrN) absorber layer has been optimized for the maximum absorptivity a * 0.9 in ZrO x /ZrC-ZrN/Zr reflector-absorber tandem structures on stainless steel (SS) and aluminum (Al) substrates, using reactive DC/RF magnetron sputtering process and varying reactive nitrogen during the deposition. The mechanical properties such as hardness and Young's modulus values increase from *19.63 to *38.53 GPa and *36.39 to *58.67 GPa, respectively, with increasing nitrogen flow rate during ZrC-ZrN absorber layer deposition on SS substrate. These values also increase with increasing load up to a critical limit and saturates thereafter with further increase in load values. The films with moderate hardness and Young's modulus exhibit enhanced solar thermal performance (a * 0.9) against films with lower and higher values of these mechanical properties, suggesting optimal nitrogen concentration for desired solar thermal performance.