A study on the properties of Zr-doped gamma-Al2O3 xerogels hybridized with alpha-Al2O3 whiskers synthesized by solvothermal drying

作者：Jung In Keun; Ha Tae Jung; Park Hyung Ho^*; Park Si Jung; Choi Doo Jin; Baek Seungsu

来源：Surface and Coatings Technology, 2013, 231: 185-188.

DOI：10.1016/j.surfcoat.2012.05.049

• ZrO2
• Al2O3
• Composite porous structure
• Al2O3 whisker
• Solvothermal drying

Hydrophobic zirconium doped alumina xerogels and zirconium doped alumina xerogels hybridized with alpha-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 gamma-phase to alpha-phase over 200 degrees C. Although phase transition temperature was increased, the porous structure of Zr-doped Al2O3 xerogel was collapsed over 1200 degrees C losing its specific surface area. To maintain their porous structures at the elevated temperatures, the Zr-doped Al2O3 xerogels were hybridized with alpha-Al2O3 whiskers. The alpha-Al2O3 whiskers were grown at 1400 degrees C and thus sustained its phase and structure over 1400 degrees C. The alpha-Al2O3 whiskers in xerogels act as a pillar at elevated temperatures. As a result, Zr doped Al2O3 xerogels hybridized with alpha-Al2O3 whiskers maintained their porous structure over 1400 degrees C even though there was a phase transition from gamma-Al2O3 to alpha-Al2O3.

• 出版日期2013-9