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《中国照明电器》2017,(10)
本文于探究制备YAG黄色荧光粉的最佳工艺参数,从而提高白光LED的发光性能和生产效率。采用了高温固相法制备Ce~(3+)掺杂铝酸盐YAG(Y_(3-x)Al_5O_(12)∶Ce_x~(3+))黄色荧光粉样品,其中x=0.02,0.04,0.06,0.08,0.1。实验以氧化钇,氧化铈,氧化铝为原料,添加不同助熔剂(硼酸,BaF_2)制得YAG,利用X射线衍射仪(XRD),扫描电子显微镜(SEM),荧光光谱分析仪(PL)等测试分析了产物的物相,形貌及发光性能等。通过对激活剂浓度不同以及助熔剂不同样品的发射光谱进行比较,得出结论:在煅烧温度1 300℃,保温时间为4 h时,当激活剂的掺杂浓度为x=0.06,生成YAG质量的3%的硼酸和3%的BaF_2混合为助熔剂时,制得的YAG∶Ce~(3+)的发光性能最好,并且在主激发光为455 nm的可见光激发下,发射光谱的发射峰值为530 nm。 相似文献
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采用了固相反应法制备了Ni0.24Cu0.21Zn0.55Fe2O4铁氧体材料,研究了制备工艺(预烧温度、烧结温度、升温速度、保温时间)及助熔剂Bi2O3对材料显微结构和电磁性能的影响.结果表明,预烧温度、烧结温度、升温速度、保温时间和助熔剂Bi2O3对NiCuZn铁氧体材料的晶粒尺寸、晶粒分布均匀度、品质因数、起始磁导率和介电常数等影响显著.通过制备工艺参数的优化,确定出适当的工艺条件:预烧温度875℃,烧结温度900℃,升温速度2℃/min,保温时间2h.利用上述工艺制得的材料,不仅具有良好的电磁性能,而且实现了低温烧结. 相似文献
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采用微波法以活性炭粒为微波吸收剂成功合成了SrMoO_4∶Tb~(3+)绿色荧光粉,利用X射线粉末衍射仪、扫描电子显微镜、荧光分光光度计等手段对样品进行分析表征,讨论了不同助熔剂对样品的物相结构、微观形貌和发光性质的影响,并确定了助熔剂的最佳用量。结果表明:所合成样品的晶体结构与SrMoO_4相似,属四方晶系结构,I4_1/a空间群。助熔剂K_2CO_3、H_3BO_3或NH_4F的加入有助于改善样品的结晶度和相纯度。未加助熔剂合成的荧光粉颗粒形貌呈不规则片状,添加助熔剂K_2CO_3、H_3BO_3或NH_4F合成的荧光粉颗粒形貌均为类球形。与未加助熔剂合成的荧光粉相比,添加助熔剂NH_4F、K_2CO_3或H_3BO_3后合成的样品发光强度分别提高了57%,21%和18%。 相似文献
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本文采用高温固相法合成BaSi_2O_2N_2∶Eu~(2+)蓝绿色荧光粉,探索了温度和时间对荧光粉性能的影响,同时通过添加助熔剂有效提升了荧光粉性能。BaSi_2O_2N_2∶Eu~(2+)荧光粉搭配YAG∶Ce~(3+)和CaAlSiN_3∶Eu~(2+)荧光粉,可以达到LED正白光段显色指数R_1~R_(15)大于90的全光谱目的。该方案解决了之前LED光源制作高显色方案中显色指数R_(12)偏低的现象,补充了白光LED缺失深蓝色的部分,对LED的推广有着重要的意义。 相似文献
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AbstractNanoscale SrAl2O4: Eu2+, Dy3+ with controllable size and morphology was synthesized by sol-gel auto-combustion method. The surface morphology and structural characterization were carried out with TEM and XRD. Optical properties were analyzed by comparing excitation spectra, emission spectra and afterglow decay of the nanoscale phosphor with that of the bulk phosphor. The results showed that citric acid acted as a soft template in the reaction system. The morphology and size changed clearly with pH value and sintering temperature. The crystallinity was affected by the quantity of citric acid. Both the nanoscale phosphors with different particle size and the bulk one have the strongest emission at 525?nm. But their strongest peaks in excitation spectra are very different from each other. The phosphorescence of nanoscale phosphor decays more rapidly than that of the bulk phosphor. 相似文献
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采用溶胶-凝胶法制备了纳米晶SmFeO_3/γ-Fe_2O_3复合粉体,然后经压制和高温烧结制备了SmFeO_3/γ-Fe_2O_3块体样品.研究了烧结温度对样品组织结构与磁性能的影响,结果表明,干凝胶经450℃预烧后,粉体样品中出现SmFeO_3相,但仍有部分非晶相存在.烧结温度对块体材料晶粒尺寸及磁性能有着显著的影响,在保温时间为1h的情况下,当烧结温度从800℃升高到1100℃时,烧结块体中SmFeO_3和γ-Fe_2O_3两相的平均晶粒尺寸分别由51nm和48nm长大到79nm和76nm,样品致密度由56%增大到72%,比饱和磁化强度从51A·m~2/kg升高到76A·m~2/kg,矫顽力从215kA/m下降到187kA/m. 相似文献
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Nanosized (1???x)BiScO3???xPbTiO3 ferroelectric ceramic powders was obtained by the metal citrate sol–gel method. The decomposition process of the polymer was studied by using infrared spectral absorption and X-ray diffraction. Perovskite phase can be obtained at the calcining temperature as low as 450 °C and the average grain sizes of powders were calculated by XRD method. The influence of the grain size by pH value of the solution is explained. The calcining temperature is proved to be the foremost factor to determine the grain size which grew from 12 to 23 nm when calcined at different temperatures. The holding time can also affect the grain size. The sintering temperature can be reduced by 100 °C using nano powders than using traditionally prepared large grain powders. 相似文献
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Sung Park Yun-Joong Chung Jae Chun Lee Kang Yoo Byoung-Woo Kim Ju-Hyeon Lee 《Journal of Electroceramics》2006,17(2-4):827-830
ZnGa2O4 phosphors were synthesized by both SCM (solution combustion method) and SSRM (solid state reaction method). The characteristics
of the both ZnGa2O4 phosphors were investigated by TGA (Thermogravimetric analysis), SEM (scanning electron microscope), BET (Brunauer Emmett
Teller), PL (photoluminescence) and XRD (X-ray diffraction). The particle size of SCM phosphor was about one-hundredth of
SSRM phosphor. The PL intensity of SCM phosphor was about 1.5 fold higher than that of SSRM phosphor. The SCM phosphor was
also tried to be doped with Mn+2 ions. The highest PL peak was observed with Mn+2 ions of 0.003 mole fraction. The peak was shifted from blue (470 nm) to green (513 nm) color. These results might be very
useful for high efficiency phosphors for displays such as field emission displays and plasma display panels. 相似文献
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Photoluminescence characteristics of Y3Al5O12:Tb3+ phosphors synthesized using the combustion method
Hyun-ho Kwak Se-Jun Kim Hyon-Hee Yoon Sang-Joon Park Hyung-wook Choi 《Journal of Electroceramics》2009,23(2-4):397-401
For this study, terbium-doped yttrium aluminum garnet (YAG:Tb) phosphor powders were prepared via the combustion process using the 1:1 ratio of metal ions to reagents. The characteristics of the synthesized nano powder were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence. Single-phase cubic YAG:Tb crystalline powder was obtained at 800 °C by directly crystallizing it from amorphous materials, as determined by XRD techniques. There were no intermediate phases such as yttrium aluminum perovskite (YAlO3) and yttrium aluminum monoclinic (Y4Al2O9) observed in the sintering process. The SEM image showed that the resulting YAG:Tb powders had uniform sizes and good homogeneity. With the increase in the sintering temperature, the grain size increased. The photoluminescence spectra of the YAG:Tb nanoparticles were investigated to determine the energy level of electron transition related to luminescence processes. There were three peaks in the excited spectrum, and the major one was a broad band of around 274 nm. Also, the YAG:Tb nanoparticles showed two emission peaks in the range of 450?×?500 and 525?×?560 nm, respectively, and had maximum intensity at 545 nm. 相似文献
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采用传统的陶瓷制备工艺,在1 060℃下分别保温2 h、4 h和6 h,制备了{0.996[0.95(Na0.5K0.5)-NbO3-0.05LiSbO3]-0.004FeBiO3}+0.15mol%CuO(简称KNN-LS-BF-0.15%Cu)压电陶瓷,研究了烧结保温时间对陶瓷性能的影响。结果表明,过短的烧结保温时间并不能促成陶瓷晶粒的长成,但超过4 h后继续延长烧结保温时间对晶粒尺寸的影响不大;随着烧结保温时间的延长,KNN-LS-BF-0.15%Cu陶瓷的压电常数d33、机电耦合系数kp和介电常数εr先升高后降低,而介电损耗tanδ和机械品质因数Qm则随之下降;当烧结保温时间为4 h时,样品具有最佳的综合性能:d33=185 pC/N,kp=0.28,εr=1054.25,tanδ=2.1%,Qm=53.39。 相似文献