Impact of aging on metal oxide-doped fluorophosphate nanopowder

Abstract

The aging behavior of silver and zinc oxide-doped fluorophosphate nanopowders, developed for orthopedic applications, was investigated to address storage stability concerns. Over 12 months, the nanopowders were analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). FTIR revealed a reduction in the O–H peak intensity from 3435 cm⁻¹ to 1633 cm⁻¹, indicating absorption of environmental CO₂/moisture and the formation of carbonates or phosphocarbonates. XRD demonstrated new crystalline peaks at 2θ angles of 15° and 30°, confirming crystallization over time. SEM images showed significant crystal growth, particularly after six months, with particles transitioning from amorphous to more crystalline forms. EDX analysis indicated a notable reduction in silver (Ag) and zinc (Zn) peaks, alongside the appearance of sodium (Na), oxygen (O), and carbon (C) peaks, pointing to environmental contamination and oxidation. These findings emphasize the need for vacuum-sealed storage to preserve the structural integrity and extend the shelf life of these nanopowders, enhancing their biomedical applications.