Low-temperature chemical routes to formation and IR properties of lanthanum sesquisulfide (La_2S_3) ceramics
Low-temperature chemical routes to formation and IR properties of lanthanum sesquisulfide (La_2S_3) ceramics
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三硫化镧(La_2S_3)陶瓷的低温化学合成途径及红外性能
DOI：
10.1557/jmr.1993.1394
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
S. Risbud
中科院分区：
文献类型：
--
作者：
P. Kumta;S. Risbud
硫化镧（La_2S_3）在结晶状态下以三种不同的同素异形体存在。低温正交相（α）转变为中间四方相（β），该四方相进一步经历高温立方相（γ）的转变。La_2S_3的立方相（γ）具有作为远红外（8-14 μ m）窗口材料的潜力。本文报道了利用金属有机合成方法，通过前驱体化学的选择和工艺的改进，制备La_2S_3的β相和γ相。烷氧基衍生的前体和转化的硫化物粉末的形貌，微观结构和热稳定性进行了表征。还进行了相演化研究，并在β和γ相形成的背景下讨论了结果。还介绍了致密化、微观结构和红外透射特性的结果。
Lanthanum sulfide (La_2S_3) exists in three different allotropic forms in the crystalline state. The low-temperature orthorhombic phase ( α ) transforms to the intermediate tetragonal phase ( β ) which further undergoes transformation to the high-temperature cubic phase ( γ ). The intermediate tetragonal phase ( β ) is an oxysulfide with possible use as a phosphor, and the cubic phase ( γ ) of La_2S_3 shows potential for application as a far IR (8–14 µ m) window material. We report metal-organic synthesis routes for the preparation of the β - and γ -phases of La_2S_3 by processing modifications and choice of precursor chemistry. The alkoxide-derived precursors and the transformed sulfide powders were characterized for morphology, microstructure, and thermal stability. Phase evolution studies were also conducted, and the results are discussed in the context of formation of the β- and γ -phases. Results of densification, microstructure, and infrared transmission characteristics are also presented.