Dual-activator luminescence of LuAG:Mn4+/Tb3+ phosphor for optical thermometry

Mn⁴⁺ and Tb³⁺ singly doped and Mn⁴⁺/Tb³⁺ codoped lutetium aluminum garnet (Lu₃Al₅O₁₂, or simply LuAG) phosphors were synthesized and investigated for the application of optical thermometry. X-ray powder diffraction and luminescence spectroscopy measurements were performed on all samples to analyze their crystal phases and optical properties. In particular, temperature-dependent luminescence of the LuAG:Mn⁴⁺/Tb³⁺ sample was measured at the temperature range of 270–420 K. The results showed that the luminescence intensity of Mn⁴⁺ has gone through a remarkable decline while the luminescence of Tb³⁺ has an only insignificant change with the rise of temperature which leads to a dramatic decrease in the fluorescence intensity ratio (FIR) between the two activator Mn⁴⁺ and Tb³⁺. Further analysis showed that the LuAG:Mn⁴⁺/Tb³⁺ sample used for temperature sensing has a high relative sensitivity with maximum value of 4.3% K⁻¹ at 333 K. Our research indicated that this LuAG:Mn⁴⁺/Tb³⁺ material is a promising candidate for FIR-type optical temperature sensing.     

Preparation and characterization of multilayer Gd2O2S:Tb phosphor screen for X-ray detection application

Gd2O2S:Tb (GOS) phosphor screen, generally with a multilayer structure, has been widely used in digital X-ray imaging. GOS phosphor screen is fabricated via a slip casting route, which is an effective method to obtain multilayer composites with good strength. The GOS slurry was prepared using the menhaden oil, polyvinyl butyral and PEG-400 as dispersant, binder and plasticizer, respectively, and slip casted on a support layer. After the GOS scintillation layer is formed, a transparent polyethylene terephthalate film is covered on it as a protective layer. The X-ray excited emission spectra of the obtained GOS phosphor screen is well match to the spectral response of a-Si:H photodiode, and the spatial resolution was close to 3.7 LP/mm, which could meet the request of the commercial application.     

Visible emission and energy transfer in Tb3+/Dy3+ co-doped phosphate glasses

In this work, we systematically study the spectroscopic properties of Tb³⁺/Dy³⁺ co-doped phosphate glasses in the visible spectral region and explore the sensitization role of Dy³⁺ in the enhancement of visible fluorescence of Tb³⁺ ions. Judd-Ofelt parameters Ω₂ and Ω₄/Ω₆ of the phosphate glass as host for Tb³⁺ are calculated as 21.60 × 10^-20 cm² and 0.73, respectively, based on the measured spectral absorption. Multiple energy transfer (ET) routes from Dy³⁺ to Tb³⁺ and their efficiencies are characterized, and the enhanced fluorescence properties of Tb³⁺ are investigated, including the emission spectral strength and the spontaneous emission lifetime as functions of Dy³⁺ doping concentration. The efficient nonradiative ET processes between Dy³⁺ and Tb³⁺ allow a moderate concentration level of Tb³⁺ to achieve favorably stronger spectral absorption at blue and ultraviolet wavelengths. Tb³⁺/Dy³⁺ co-doped phosphate glass shows promising potential for phosphors and lasing operation at visible wavelengths.     

晶界扩散Tb对烧结Nd-Fe-B组织与磁性能的影响

用磁控溅射法在烧结Nd-Fe-B磁体表面沉积Tb金属薄膜并进行晶界扩散处理,对比经不同热扩散温度及时间处理后的磁体组织和磁性能变化。结果表明,925℃×10 h+500℃×2 h为最佳晶界扩散工艺,可将磁体矫顽力提高到1630.9 kA·m^-1,较原始磁体提升50%,同时剩磁和磁能积无明显下降,磁体仍具有较高的退磁曲线方形度。晶界扩散处理后磁体取向度有所提高,主相晶粒表面形成了明显的富Tb壳层结构,其厚度随离开磁体表面距离的增加逐渐变薄,随热扩散温度升高和时间延长逐渐增厚。长时间热扩散处理使磁体内形成沿晶界分布的连续薄层富Nd相,将主相晶粒彼此分隔,有效降低磁性相颗粒间交换耦合作用。能谱(EDS)分析表明,适当的热扩散工艺可使Tb元素扩散至磁体芯部,渗透厚度4 mm的磁体。     

Fabrication and investigation of Ca/Tb co-doped HfO2 infrared coatings

In this study, Ca/Tb co-doped HfO₂ coatings were prepared by atmosphere plasma spraying. The chemical composition, morphology and infrared property of the coatings were characterized. The coatings possessed a layer-stacked morphology. When the Ca/Tb doping atomic ratio was 1:1, the phase of the coatings gradually changed from monoclinic to cubic with increasing the doping mass. The CTH2 coating had the highest emissivity which was 0.820 in 0.75–6.5 µm and 0.902 in 6.5–15 µm respectively. The enhancement in short band was mainly due to the introduction of Ca²⁺ and Tb³⁺ ions that generated oxygen vacancies in the lattice forming impurity levels within the forbidden band, moreover, the transfer of Tb³⁺ to Tb⁴⁺ increased the concentration of free electrons, which promoted the absorption of free carriers. The increase in long band attributed to the lattice distortion that reduced the lattice symmetry and strengthened the absorption of lattice polar vibration.     

KCaPO4:Tb3+绿色荧光粉的发光特性

采用高温固相法合成了KCaPO4:Tb3+绿色荧光粉,并研究了材料的发光性质.KCaPO4:Tb什材料呈多峰发射,发射峰为437、490、545、587和623nm,分别对应Tb3+的5D3→F4和5D4→FJ=615,4,3跃迁发射,主峰为545nm;监测545nm发射峰,所得激发光谱由4f7 5d1宽带吸收(200...     

Tb4O7掺杂Cr2O3-TiO2基高发射率涂层结构及辐射性能研究

目的提高Cr_2O_3-TiO_2基陶瓷涂层的辐射性能。方法以Cr_2O_3、TiO_2、NiO、Tb_4O_7为原料,经喷雾干燥及高温烧结致密化处理,制备成具有尖晶石和钙钛矿混合结构的Cr_2O_3-TiO_2基复合团聚型粉体,利用大气等离子喷涂法在TC4钛合金表面制备Tb_4O_7掺杂型Cr_2O_3-TiO_2基陶瓷涂层。采用扫描电子显微镜、X射线衍射仪、IRE-2红外辐射测试仪,分别对样品的显微组织结构、物相组成及辐射性能进行了表征。结果团聚造粒后,复合粉体的球形度和流动性较好,可满足等离子喷涂连续使用。所制备的Cr_2O_3-TiO_2基陶瓷涂层的熔化状态较好,扁平化程度较高,涂层中掺杂的Tb元素分布均匀。Tb~(4+)、Tb~(3+)等稀土元素离子,取代NiCr_2O_4尖晶石结构中半径相近的Ni~(2+)、Cr~(3+),导致单一晶体结构的整齐度被破坏,晶胞体积的变化引起晶体结构产生畸变,辐射条带显著加强和宽化。随着Tb_4O_7掺杂量的增多,涂层发射率逐渐上升,当掺杂量达到7.5%时,涂层在600℃的法向全发射率达到0.91。结论 Tb_4O_7稀土氧化物的加入可以有效提高Cr_2O_3-TiO_2基陶瓷涂层的发射率,稀土掺杂诱发尖晶石晶体结构畸变,从而改善涂层的辐射性能。     

Synthesis and characterization of core/shell structured nanophosphors CePO_4:Tb@LaPO_4 by solvothermal method

Core/shell structured CePO4:Tb(III) @LaPO4 and CePO4:Tb(III) were successfully synthesized in tris(2-ethylhexyl) phosphate(TEHP) and diethylene glycol(DEG) solvents for comparison of the two techniques in open air and closed reaction vessel.Morphology and crystal structure of the core/shell nanophosphors were determined by using X-ray diffraction(XRD) and transmission electron microscopy(TEM) ,which showed that nanophosphors had diameter of about 5-10 nm with the monoclinic monazite phase.The nanophosphors ...     

Tb2TiO5-Dy2TiO5中子吸收材料的显微组织及性能

以Tb₄O₇粉、Dy₂O₃粉和TiO₂粉为原料,采用高能球磨、冷等静压和高温烧结工艺制备了Tb₂TiO₅-30%(质量分数)Dy₂TiO₅中子吸收材料,研究不同球磨时间(0~48 h)下混合粉体的微观结构,不同烧结温度(1 200~1 400℃)与时间(1~96 h)下烧结块体材料的微观结构、热物理性能和耐腐蚀性能。结果表明:混合粉体的晶粒尺寸随球磨时间的延长而减小,球磨12 h后即可获得均匀混合的纳米晶粉体,纳米晶混合粉体在1 300℃烧结96 h获得了具有高致密度正交晶体结构Tb₂TiO₅-Dy₂TiO₅块体材料;该块体材料在500℃的热导率和热膨胀系数分别为2.2 W·m^-1·K^-1和5.8×10^-6 K^-1,在360℃/18.6 MPa去离子水中的腐蚀速率变化很小,平均腐蚀速率为0.18 mg·dm^-2·h^-1,该块体材料具有较高的热导率、较低的热膨胀系数以及较好的耐高温水腐蚀性能,是控制棒用中子吸收材料较优的候选材料。