A comparative approach to synthesis and sintering of alumina/yttria nanocomposite powders using different precipitants

作者：Kafili G; Movahedi B^*; Milani M

来源：Materials Chemistry and Physics, 2016, 183: 136-144.

DOI：10.1016/j.matchemphys.2016.08.011

• Ceramics
• Nanostructures
• Optical materials
• Sintering

Alumina/yttria nanocomposite powder as an yttrium aluminum garnet (YAG) precursor was synthesized via partial wet route using urea and ammonium hydrogen carbonate (AHC) as precipitants, respectively. The products were characterized using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectroscopy. The use of urea produced very tiny spherical Y-compounds with chemical composition of Y-2(CO3)(3)center dot nH(2)O, which were attracted to the surface of alumina nanoparticles and consequently, a core shell structure was obtained. The use of ammonium hydrogen carbonate produced sheets of Y-compounds with chemical composition of Y(OH)CO3 covering the alumina nanoparticles. A fine-grained YAG ceramic (about 500 nm), presenting a non-negligible transparency (45% RIT at IR range) was obtained by the spark plasma sintering (SPS) of alumina-yttria nanocomposite synthesized in the urea system. This amount of transmission was obtained by only the sintering of the powder specimen without any colloidal forming process before sintering or adding any sintering aids or dopant elements. However, by spark plasma sintering of alumina-yttria nanocomposite powder synthesized in AHC system, an opaque YAG ceramic with an average grain size of 1.2 mu m was obtained.

• 出版日期2016-11-1