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本文采用固相烧结法制备了ZrV2-xPxO7(x=0, 0.2, 0.4, 0.6, 0.8, 1)系列材料. 粉末X射线衍射(XRD)分析表明, 所制备材料的结构为单一立方相. 应用变温拉曼光谱研究该材料相变, 变温拉曼光谱研究结果表明, 材料起始相变温度随着P5+ 替代V5+ 量的增加逐渐降低, x=0, 0.4, 0.8, 1对应的相变温度分别为383 K, 363 K, 273 K, 213 K. 热膨胀测试结果表明: 随着P替代量的增加正—负膨胀转变温度先降低后增加, x=0, 0.2, 0.4, 0.6, 0.8, 1对应的正—负膨胀转变温度分别为429 K, 403 K, 372 K, 390 K, 398 K和435 K. 本文指出了该系列材料存在两个相变过程, 为设计和制备ZrV2O7基室温附近的负热膨胀材料奠定了良好的基础.ZrV2-xPxO7 (x = 0, 0.4, 0.8, 1.0) solid solutions are prepared using a solid state reaction method. Powder X-ray diffraction (XRD) analysis reveals that the as-prepared solid solutions are of single-phase cubic type in crystal structure. Temperature dependent Raman spectroscopic studies demonstrate that the phase transition temperature of ZrV2-xPxO7 decreases with the increase of the content of P. ZrV2O7, ZrV1.6P0.4O7, ZrV1.2P0.8O7 and ZrVPO7 transform from a 3× 3× 3 superstructure to a 1× 1× 1 normal structure at about 373 K, 363 K 273 K and 213 K, respectively. The results of thermal expansion testing indicate that the temperature of positive thermal expansion changes to negative thermal expansion with the increase of P content. The temperatures of positive-to-negative thermal expansion of ZrV2-xPxO7 are 429 K, 403 K, 372 K, 390 K, 398 K and 435 K for x=0, 0.2, 0.4, 0.6, 0.8 and 1, respectively. Two phase change transformations are demonstrated in ZrV2-xPxO7 materials in our work, which is beneficial for preparing the negative thermal expansion materials at room temperature using ZrV2O7.
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Keywords:
- negative thermal expansion /
- phase transitions /
- Raman spectroscopy







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