The Fe-Cu Metastable Nano-scale Compound for Enhanced Absorption in the UV–Vis and NIR Ranges

Abstract

This paper investigates the synthesis, microstructural characterization, electrical and optical, and thermal testing of Fe-Cu metastable alloy system for selective solar absorption applications. The system is produced by mechanical alloying using high-energy ball milling while monitoring its crystallographic morphology via X-ray diffraction from the initial as-is mixture up to the one produced after 8 hours milling time. The resulting homogeneous, metastable microstructure is examined by scanning electron microscopy and energy dispersive X-ray spectroscopy to verify the sought result of efficient inter-diffusion of elements. Optical spectroscopy results exhibit up to 81 pct enhanced absorption in the UV–Vis–NIR wavelength range with increased milling time from the as-is compound to the one obtained after 8 hours, while the trends of absorptivity curves had clear correlations with microstructural evolution. The impedance measurement of the resulting compound shows an increase in the resistance up to 120 Ω, compared with zero for the as-is starting mixture, which is a useful observation for many applications.