Novel Temperature Dependent Process for α-Al₂O₃ Platelets

Abstract:

α-Al₂O₃ platelets were prepared in the interface of Na₂O-CaO-SiO₂ glass induced by Al. Phase identification was accomplished by X-ray diffraction analysis. The morphology of the platelets was observed using an Environmental Scanning Electron Microscopy (ESEM). The changes for the mixtures of the Al powders and the glass powders that occurred during heating were characterized by a combination of differential scanning calorimetry (DSC) and thermalgravimety(TG) on a multi-functional instrument. Confirmed by XRD and ESEM, at 1200°C, the prepared platelets have mean diameters between 400nm and 1000nm. Most of them are aggregated and part of them through intergrowth. The crystals develop from the interface between glass and Al, and can form good moistening with the glass matrix. DSC/TG shows that γ-Al₂O₃ formed by oxidation of Al, transforms into α-Al₂O₃ and grow into the platelet α-Al₂O₃ crystals owing to the molten Al and the molten glass. On the other hand, part of the molten Al erodes into the glass and makes the deviation of the Na₂O-CaO-SiO₂ ternary system into Na₂O-Al₂O₃-SiO₂ ternary system, resulting in the formation of NaAlSiO₄.

• Periodical: Applied Mechanics and Materials (Volumes 182-183)
• Pages: 104-109
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.182-183.104
• Online since: June 2012
• Authors: Cheng Long Yu, Xin Hao, Hong Tao Jiang, Li Li Wang, Zheng Guang Zhang, Xiu Feng Wang, She Bao Lin, Juan Dong
• Keywords: Aluminum (Al), Growth Mechanism, Na₂O-Cao-SiO₂ Glass, Platelet α-Al₂O₃

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