Near-Infrared Reflectance, Thermal Shielding, and Corrosion Resistance of Neodymium-Modified Zinc Aluminate Spinel-Based Zinc Phosphate Coatings

Abstract

Given the increasing demand for energy-efficient and durable coatings, particularly in outdoor environments, this study investigates the development of lavender-shaded neodymium (Nd)-modified zinc aluminate pigment for thermal energy-saving applications. The results evidence the potential of incorporating this Nd-modified ZnAl₂O₄ pigment in zinc phosphate (ZP) coating to tune the morphology, microstructure, near-infrared (NIR) reflectance, thermal shielding, and corrosion resistance capability. The study provides a detailed elucidation of the mechanism of pigment particles’ incorporation into ZP coating, revealing enhanced nucleation and crystal size refinement, leading to denser coating with improved NIR reflectance and corrosion resistance, with aesthetic requirements potentially suitable for outdoor environments. Quantitative analysis reveals a maximum NIR reflectance of 93%, thermal shielding capacity with a temperature difference of 15.4 °C, and a more than threefold reduction in corrosion current density. The study underscores the potential of these coatings for energy-saving applications and outdoor use, highlighting their stability and effectiveness in various environmental conditions.