Gd2O2S:Tb闪烁陶瓷的制备、微结构与性能研究

Fabrication, microstructure and properties of Gd2O2S:Tb scintillation ceramics

  • 摘要: Gd2O2S:Tb闪烁陶瓷因其具有高中子吸收截面、高光输出以及优异的光谱匹配性能,同时避免了传统中子粉体闪烁屏中气泡、粉体颗粒和粘结剂之间存在的光学损耗问题,显著提高了辐照稳定性与使用寿命,因此在中子成像领域展现出良好的应用前景。为制备组分均匀、分散性优异且烧结活性高的Gd2O2S:Tb粉体,本研究以Gd2O3粉体、Tb(NO3)3及H2SO4为初始原料,经90 ℃热水浴反应生成前驱体,随后在空气氛围中煅烧(600 ℃×3 h)得到Gd2O2SO4粉体,再通过氢气还原(750 ℃×2.5 h)制得Gd2O2S:Tb粉体。结合热水浴反应机理分析,通过调控初始Gd2O3粉体的形貌,优化了Gd2O2S:Tb粉体的形貌特性。对比研究了不同Gd2O3粉体(包括商业纳米、液相沉淀法合成、商业微米以及球磨商业微米Gd2O3粉体)对Gd2O2S:Tb粉体形貌的影响,结果表明,采用商业纳米Gd2O3粉体制备的Gd2O2S:Tb粉体具有较小的片层尺寸、较均匀的分散性以及较高的烧结活性。以商业纳米Gd2O3粉体为原料制备的Gd2O2S:Tb粉体经真空预烧(1300 ℃×3 h)结合热等静压烧结后处理(1350 ℃×3 h,176 MPa)制备的Gd2O2S:Tb陶瓷(厚度为1 mm),表现出最高的光学总透过率(11.3%@545 nm)和最强的X射线激发发光强度。然而,陶瓷内部存在的Gd2O3第二相对进一步提升Gd2O2S:Tb陶瓷的光学质量产生了一定影响。

     

    Abstract: Gd2O2S:Tb scintillation ceramics exhibit a high neutron absorption cross-section, high light output, and excellent spectral matching performance. These ceramics eliminate optical losses associated with bubbles, powder particles, and binders commonly observed in traditional neutron powder scintillation screens. Gd2O2S:Tb ceramics enhance irradiation stability and extend service life, offering promising applications in neutron imaging. To obtain Gd2O2S:Tb powders with homogeneous composition, superior dispersion, and high sintering activity, precursors were synthesized from Gd2O3 powders, Tb(NO3)3, and H2SO4 via a hot water-bath reaction at 90 ℃. The precursors were transformed into Gd2O2SO4 after air calcination at 600 ℃ for 3 h. Subsequent hydrogen reduction at 750 ℃ for 2.5 h yielded Gd2O2S:Tb powders with smaller lamellar particle size and more uniform dispersion. The morphology of the Gd2O2S:Tb powders was optimized by modulating the morphology of the initial Gd2O3 powders in combination with an analysis of the hot water-bath reaction mechanism. The influence of different Gd2O3 powders (commercial nano-, precipitation -synthesized, commercial micron-, and ball-milled commercial micron- Gd2O3 powders) on the morphology of Gd2O2S:Tb powders was investigated. Gd2O2S:Tb powders with smaller lamellar size, more uniform dispersion, and higher sintering activity were obtained using commercial nano-Gd2O3 powders. The Gd2O2S:Tb ceramics prepared from commercial nano-Gd2O3 powders via vacuum pre-sintering at 1300 ℃ for 3 h and hot isostatic pressing post-treatment at 1350 ℃ for 3 h under 176 MPa exhibited the highest total optical transmittance of 11.3%@545 nm (1 mm thickness) and the highest X-ray excited luminescence intensity. However, the presence of a secondary phase of Gd2O3 within the ceramics limits further improvement in the optical quality of Gd2O2S:Tb ceramics.

     

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