ABSTRACT

A series of phosphate glasses defined by the composition 50Na₂O-xNb₂O₅-(50-x)P₂O₅ (0<x < 25 mol%) and designated as Nb5, Nb10, Nb15, Nb20, Nb25, respectively, have been elaborated by the melt quenching method, and their structural and optical properties were investigated. It was found that their density and molar volume increase and decrease with the Nb₂O₅ content, respectively. The analysis of the glasses structure by Raman spectroscopy allowed the identification of several phosphate structural units, mainly metaphosphate and pyrophosphate, and showed that niobium adopts an octahedral oxygen environment, forming linkages such as Nb-O-P and Nb-O-Nb within the network. Glass-ceramics were obtained by controlled heat treatments of the parent glasses. The heat treatment of the high niobium concentration glass Nb25 at 650°C led to the formation of the sodium niobate phase with cubic symmetry. Its microstructure was analyzed by SEM. The study of the dielectric properties of the glass-ceramics and their energy storage performance presented an optimum discharge density for the glass-ceramic with 25 mol% Nb₂O₅ and an energy efficiency of 82.5%.

摘要

由组成 50Na ₂ O-xNb ₂ O ₅ -(50-x)P ₂ O ₅ (0<x < 25 mol%)定义的一系列磷酸盐玻璃，分别指定为 Nb5、Nb10、Nb15、Nb20、Nb25 ，已经通过熔体淬火方法进行了阐述，并研究了它们的结构和光学性能。发现它们的密度和摩尔体积随着 Nb ₂ O ₅内容，分别。通过拉曼光谱对玻璃结构的分析可以识别出几种磷酸盐结构单元，主要是偏磷酸盐和焦磷酸盐，并表明铌采用八面体氧环境，在网络内形成 Nb-OP 和 Nb-O-Nb 等键。通过对母体玻璃进行受控热处理获得微晶玻璃。在 650°C 下对高铌浓度玻璃 Nb25 进行热处理导致形成立方对称的铌酸钠相。通过SEM分析其微观结构。对微晶玻璃介电性能及其储能性能的研究表明，Nb ₂ O ₅含量为 25 mol% 的微晶玻璃具有最佳放电密度 和82.5%的能源效率。