Details

Autor(en) / Beteiligte

• Kuo, Chia-Liang
• Wang, Cheng-Li
• Chen, Te-Yuan
• Chen, Guo-Ju
• Hung, I-Ming
• Shih, Chi-Jen
• Fung, Kuan-Zong

Titel

Low temperature synthesis of nanocrystalline lanthanum monoaluminate powders by chemical coprecipitation

Ist Teil von

• Journal of alloys and compounds, 2007-08, Vol.440 (1), p.367-374

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2007

Quelle

ScienceDirect

Beschreibungen/Notizen

• Nanocrystalline lanthanum monoaluminate (LaAlO 3) powders were prepared by chemical coprecipitation using 25 vol.% of NH 4OH, 0.05 M La(NO 3) 3·6H 2O and 0.05 M Al(NO 3) 3·9H 2O aqueous solutions as the starting materials. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analyses (TGA/DTA), X-ray diffraction (XRD), Raman spectrometry, specific surface area (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) were utilized to characterize the LaAlO 3 powders prepared by chemical coprecipitation. The crystallization temperature of the LaAlO 3 precursor gels precipitated at pH 9 is estimated as 810 °C by TG/DTA. The XRD pattern of the LaAlO 3 precursor gels precipitated at pH 8–12 and calcined at 700 °C for 6 h shows a broad arciform continuum exist between 24° and 32° and sharp peaks of LaAlO 3 except the precursor gels precipitated at pH 9. For the LaAlO 3 precursor gels precipitated at pH 9 and calcined at 700 °C for 6 h, the formation of the perovskite LaAlO 3 phase occurs and the presence of crystalline impurities is not found. The crystallite size of LaAlO 3 slightly increases from 37.8 to 41.5 nm with calcination temperature increasing from 700 to 900 °C for 6 h. The LaAlO 3 powders prepared by chemical coprecipitation have a considerably large specific surface of 30 m 2/g. The relative density greater than 97% is obtained when these nanocrystalline LaAlO 3 powders are sintered at 1550 °C for 2 h.