Preparation of neodymium-doped yttrium aluminum garnet powders and fibers

• 作 者: R. López J. Zárate E. A. Aguilar J. Muoz-Saldaa
• 机 构: Instituto de Investigaciones Metalurgicas, UMSNH, Morelia,Centro de Investigación y de Estudios Avan
• 出 处: Journal of Rare Earths
• 发表日期: 2008年05期
• 关键词: neodymium powders garnet yttrium spray crystalline citrate diameters amorphous c

Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi- num garnet (YAG) phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 °C us- ing the spray-drying methodology whilst conventional approaches currently available require 1000 °C. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization (spray dryer) to obtain aggregated precursor powders of the compound. These aggregates were calcined at 800, 850 and 900 °C to determine the phase evolution from amorphous to crystalline by X-ray diffraction (XRD). The morphology of aggregates was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, through XRD it was determined that the crystallization of YAG phase started at about 800 °C without any intermediate phases. The powders were composed of spherical aggregates with an average diame- ter of 1 μm. From these powders, ceramic fibers with additions of 2at.% and 5at.% Nd, were extracted from the melt with diameters ranging from 30 μm to 50 μm.

Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi- num garnet (YAG) phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 ° C us - ing the spray Dry Hay Dialectical Technologies currently available require 1000 ° C. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization (spray dryer) to obtain These aggregates were calcined at 800, 850 and 900 ° C to determine the phase evolution from amorphous to crystalline by X-ray diffraction (XRD). The morphology of aggregates was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, through XRD it was determined that the crystallization of YAG phase started at about 800 ° C without any intermedi The powders were composed of spherical aggregates with an average diameter of 1 μm. From these powders, ceramic fibers with additions of 2 at.% and 5 at.% Nd, were extracted from the melt with diameters ranging from 30 μm to 50 μm.