Synthesis of Ca-α-SiAlON phosphors by a mechanochemical activation route
Synthesis of Ca-α-SiAlON phosphors by a mechanochemical activation route
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DOI：
10.1016/j.actamat.2010.11.021
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发表时间：
2011-02
期刊：
影响因子：
9.4
通讯作者：
Xin Xu;Jia-Ye Tang;T. Nishimura;L. Hao
中科院分区：
文献类型：
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作者：
Xin Xu;Jia-Ye Tang;T. Nishimura;L. Hao
以β-Si 3 N4、AlN、Al 2 O3、CaO和Eu 2 O3为原料，采用机械化学活化法合成了Eu 2+掺杂的Ca-α-SiAlON荧光粉。机械研磨主要将起始粉末混合物转化为含有大量分散良好的纳米晶β-Si 3 N4晶粒的非晶相。在非晶相中实现了元素在原子水平上的均匀性。未球磨粉体中α-SiAlON晶粒的形成机制是通过溶解-扩散-再沉淀过程，导致Eu 2+离子在主相中分布不均匀。机械活化显著促进了起始粉末在后退火过程中的反应，由均匀的亚稳非晶相快速析出，直接形成由纳米晶组成的α-SiAlON晶粒。这种新的化学上不利的方法导致Eu 2+在α-SiAlON晶体中的均匀分布，从而改善了光致发光。机械化学活化路线有望适用于合成各种各样的纳米（氧）氮硅酸盐磷光体，具有改善的均匀性和光致发光效率。
Fine Eu2+-doped Ca-α-SiAlON phosphors have been synthesized by a novel mechanochemical activation route from stoichiometric mixtures of β-Si3N4, AlN, Al2O3, CaO and Eu2O3. Mechanical milling mostly transformed the starting powder mixture into an amorphous phase that contained a large number of well-dispersed nanocrystalline β-Si3N4grains. Homogeneity of elements at the atomic level was achieved in amorphous phase. The formation mechanism of α-SiAlON grains in unmilled powders was through a solution–diffusion–reprecipitation process, leading to an inhomogeneous distribution of Eu2+ions in the host phase. Mechanical activation significantly promoted the reaction among the starting powders during post-annealing, and α-SiAlON grains composed of nanocrystals with the intended composition formed directly through rapid precipitation from the homogeneous metastable amorphous phase. This novel thermodynamically unfavorable approach leads to the homogeneous distribution of Eu2+in α-SiAlON crystals resulting in improved photoluminescence. The mechanochemical activation route is expected to be applicable to the synthesis of a wide range of nanosized (oxo)nitridosilicate phosphors with improved homogeneity and photoluminescence efficiency.