کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1657720 | 1517647 | 2013 | 4 صفحه PDF | دانلود رایگان |
Hydrophobic zirconium doped alumina xerogels and zirconium doped alumina xerogels hybridized with α-Al2O3 whisker were fabricated by Si(CH3)3 (trimethylsilyl substituent) modification of alcogels via ambient pressure solvothermal drying procedure. One-step solvent exchange and surface modification were simultaneously progressed by immersing alumina alcogels in hexamethyldisilazane/hexane solution. The synthesized Zr doped Al2O3 xerogels have shown increased phase transition temperature from γ-phase to α-phase over 200 °C. Although phase transition temperature was increased, the porous structure of Zr-doped Al2O3 xerogel was collapsed over 1200 °C losing its specific surface area. To maintain their porous structures at the elevated temperatures, the Zr-doped Al2O3 xerogels were hybridized with α-Al2O3 whiskers. The α-Al2O3 whiskers were grown at 1400 °C and thus sustained its phase and structure over 1400 °C. The α-Al2O3 whiskers in xerogels act as a pillar at elevated temperatures. As a result, Zr doped Al2O3 xerogels hybridized with α-Al2O3 whiskers maintained their porous structure over 1400 °C even though there was a phase transition from γ-Al2O3 to α-Al2O3.
► Al2O3 xerogel is synthesized by sol–gel method using solvothermal drying.
► Phase transition temperature increased with 1.0 at.% Zr doped Al2O3 xerogel.
► Zr doped Al2O3 xerogel composite with α-Al2O3 whisker to increase thermal stability.
► AlOZr network was maintained in Zr doped Al2O3 xerogel composite with α-Al2O3 whisker.
► The characteristics of hybridized Zr doped Al2O3 xerogels were analyzed.
Journal: Surface and Coatings Technology - Volume 231, 25 September 2013, Pages 185–188