硅酸盐学报

Sr_1-_xNa_xNb₅O₁₅固溶体系陶瓷的结构与电性能

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郝蕊 ¹ , 邓卓 ² , 马占营 ¹ , 于天淼 ¹ , 曹梦馨 ¹ , 魏灵灵 ²

硅酸盐学报 | 研究论文 2026,54(6): 1980-1990

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硅酸盐学报 |研究论文 2026 , 54 (6) : 1980 -1990

Sr_1-_xNa_xNb₅O₁₅固溶体系陶瓷的结构与电性能

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郝蕊¹, 邓卓², 马占营¹, 于天淼¹, 曹梦馨¹, 魏灵灵²

作者信息

^1．咸阳师范学院化学与化工学院，陕西咸阳 712000

^2．陕西师范大学化学化工学院，西安 710119

通讯作者:

魏灵灵（1984—），女，博士，教授。

作者简介:

郝蕊（1997—），女，硕士，助理实验师。

Structure and Electrical Properties of Sr_1-_xNa_xNb₅O₁₅ Solid Solution Ceramic Systems

Rui HAO¹, Zhuo DENG², Zhanying MA¹, Tianmiao YU¹, Mengxin CAO¹, Lingling WEI²

Affiliations

^1.School of Chemistry and Chemical Engineering, Xianyang Normal University, Xianyang 712000, Shaanxi, China

^2.School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China

Corresponding Author:

{WEI} Lingling (1984-), female, Ph.D., Professor. E-mail: weill@snnu.edu.cn

HAO Rui (1997-), female, Master, Assistant experimentalist. E-mail: 1021263538@qq.com

出版时间: 2026-05-13 doi: 10.14062/j.issn.0454-5648.20250708

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摘要

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从SrNb₂O₆-NaNbO₃的二元固溶相图出发，通过传统固相法合成了一系列Sr_1-_xNa_xNb₅O₁₅（SNN，0.56 ≤ x ≤ 1.06）陶瓷材料，通过X射线衍射、扫描电子显微镜和电性能实验，研究了第二相对SNN陶瓷结构、介电、铁电性能的影响并确定了SNN纯相的组成条件和温度范围。结果表明：当x = 0.71~0.80时，陶瓷在1200~1360 ℃范围内可获得稳定的纯相，且SNN纯相的存在取决于陶瓷的组成和烧结温度。当x = 0.71~0.88范围内时，SNN陶瓷的电学性能相对较好，x = 0.80的陶瓷表现出优异的铁电性能：P_r = 11.49 μC/cm²，E_c = 20.99 KV/cm。

关键词

铌酸锶-铌酸钠二元固溶体 / 陶瓷组分 / 烧结温度 / 铁电性能

Abstract

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Introduction

As an important branch of lead-free piezoelectric materials, ceramics with a tetragonal tungsten bronze (TTB) structure have a high spontaneous polarization strength, high Curie temperature (T_C), and beneficial dielectric properties, making them particularly useful in ferroelectric applications. Depending on which sites are filled, the TTB structure can be divided into three categories, i.e., the "stuffed" structure, the "filled" structure and the "unfilled" structure. As a typical "filled" TTB compound, the Sr₂NaNb₅O₁₅ (SNN) ceramics can be regulated through compositional design to exhibit a wide range of structures and functional characteristics, which have a broad development potential in the fields of dielectric energy storage, multiferroic materials, nonlinear optics, and pyroelectric sensors. However, SNN ceramics require relatively high sintering temperatures, and the secondary phase Na_0.5Sr_0.25NbO₃ (NSN) readily forms during the sintering process, which adversely affects the electrical properties. Although some previous studies used the methods of eliminating the impurity phase, there could be few studies on the relationship between impurities and the properties of SNN ceramics. In this paper, SNN ceramics (i.e., Sr_1-_xNa_xNb₅O₁₅, 0.56 ≤ x ≤ 1.06) were prepared with the SrNb₂O₆ (SN)-NaNbO₃ (NN) binary solid solution system, to examine the relationship among the presence of the secondary phases and the ceramic composition, as well as the sintering temperature.

Methods

SN and NN powders were synthesized by a solid-state method with reagent-grade SrCO₃ (99.99%), Na₂CO₃ (99.99%), and Nb₂O₅ (99.99%) as raw materials. The starting raw materials were pre-dried at 120 ℃ for 24 h, and then weighed according to the target stoichiometric ratios. The powders were thoroughly mixed in ethanol in a planetary ball mill with ZrO₂ balls at 401 r/min for 20 h. The mixtures were dried at 80 ℃ for 24 h, and then calcined at their respective suitable temperatures. Subsequently, the SN and NN powders were obtained by separately grinding the calcined products in a mortar after natural cooling. Afterwards, SNN ceramics (Sr_1-_xNa_xNb₅O₁₅, 0.56 ≤ x ≤ 1.06) were synthesized with polycrystalline SN and NN according to the desired SNN compositions, calcined at 1220 ℃ for 6 h, and uniaxially compacted into pellets with a binder (namely 5% polyvinyl alcohol). The binder was removed at a high temperature. Finally, SNN ceramics were prepared by sintering at 1280-1340 ℃ for 4 h.

The effect of the secondary phases on the structure of SNN ceramics was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and field emission transmission electron microscopy (FETEM). Furthermore, the ceramics were ground and polished down to a thickness of about 0.6 mm, coated with silver electrodes, and fired at 840 ℃ for 30 min. Their dielectric characteristics and piezoelectric coefficients d₃₃ were measured by the LCR meter and quasi-static piezoelectric meter. The ceramics were also ground and polished down to a thickness of about 0.2 mm and coated with gold electrodes to record the room-temperature ferroelectric hysteresis loops by a Radiant Precision Workstation.

Results and discussion

The required composition and sintering temperature ranges of the SNN pure phase are determined. For Na⁺contents (x) of 0.56-0.68, SN-NN can be solidly dissolved to obtain a pure phase at high temperatures (i.e., > 1280 ℃). As x = 0.71 and 0.80, SN-NN can be solidly dissolved at 1200-1360 ℃. At the Na⁺ content of 0.88, the SN-NN solid solution can be obtained, but it decomposes at higher temperatures (> 1320 ℃), accompanying the formation of the secondary NN phase. As the Na⁺ content further increases, it cannot be solidly dissolved at 1200-1360 ℃.

The maximum density is obtained for SNN ceramics sintered at 1340 ℃, and the change in Na⁺ content has little effect on the microstructure. The T_C of SNN ceramics increases from 272 ℃ as x = 0.56 to 323 ℃ as x = 0.88 because the crystal structure changes from "unfilled" to "filled" as the Na⁺ content increases, thus affecting the degree of crystal distortion. T_C gradually decreases because a minor amount of NN appears at x of 0.88. The dielectric constant (ε_r) of SNN ceramics initially increases and then decreases, exhibiting a maximum of 1664 as x = 0.80. The dielectric loss (tanδ) remains at a low value at this point. The remnant polarization P_r (11.49 μC/cm²) and coercive field E_c (20.99 kV/cm) are both nearly maximized as x = 0.80 for SNN ceramics due to the "filled" TTB structure, and the maximum d₃₃ value of 34 pC/N is obtained for SNN ceramics as x = 0.80, which is consistent with the optimal composition for ferroelectric properties.

Conclusions

Based on the XRD patterns, the ceramics with a stable, pure TTB phase could be obtained by sintering at 1200-1360 ℃ when x = 0.71-0.80, and the existence of this phase depended on the ceramic composition and the sintering temperature. As the Na⁺ content increased, T_C initially increased because the filling degree of the TTB structure increased, and then gradually decreasesd when x > 0.88 because the increase in Na⁺ content induced the formation of the secondary NN phase. When x=0.71-0.88, the electrical properties could be optimal. The ceramic with x of 0.80 demonstrated a high ferroelectric performance (i.e., P_r = 11.49 μC/cm², and E_c = 20.99 kV/cm). This study could provide certain theoretical basis and technical support for the subsequent studies of SNN ceramics.

Key words

strontium niobate-sodium niobate binary solid solution / ceramic concentration / sintering temperature / ferroelectric performance

引用本文

郝蕊, 邓卓, 马占营, 于天淼, 曹梦馨, 魏灵灵. Sr_1-_xNa_xNb₅O₁₅固溶体系陶瓷的结构与电性能. 硅酸盐学报, 2026 , 54 (6) : 1980 -1990 . DOI: 10.14062/j.issn.0454-5648.20250708

Rui HAO, Zhuo DENG, Zhanying MA, Tianmiao YU, Mengxin CAO, Lingling WEI. Structure and Electrical Properties of Sr_1-_xNa_xNb₅O₁₅ Solid Solution Ceramic Systems[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (6) : 1980 -1990 . DOI: 10.14062/j.issn.0454-5648.20250708

基金

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国家自然科学基金面上项目(22475125)
陕西省教育厅科学研究计划(24JK0709)
陕西省科技厅自然科学基础研究计划(2025JC-YBQN-503)
咸阳师范学院科研计划(XSYK24029)

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2026年第54卷第6期

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doi: 10.14062/j.issn.0454-5648.20250708

接收时间：2025-09-24
首发时间：2026-10-22
出版时间：2026-05-13

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收稿日期：2025-09-24
修回日期：2026-02-04

基金

国家自然科学基金面上项目(22475125)

陕西省教育厅科学研究计划(24JK0709)

陕西省科技厅自然科学基础研究计划(2025JC-YBQN-503)

咸阳师范学院科研计划(XSYK24029)

作者信息

^1．咸阳师范学院化学与化工学院，陕西咸阳 712000

^2．陕西师范大学化学化工学院，西安 710119

通讯作者:

魏灵灵（1984—），女，博士，教授。

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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