کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1477579 991188 2008 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Sintering behaviour and microstructural evolution of ultrapure α-alumina containing low amounts of SiO2
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Sintering behaviour and microstructural evolution of ultrapure α-alumina containing low amounts of SiO2
چکیده انگلیسی

The effect of small additions of silica (SiO2) on the densification and microstructural evolution of an ultrapure α-alumina (Al2O3) has been investigated. The role of SiO2 on the sintering behaviour was elucidated through an extensive dilatometric study performed on pure alumina and on doped samples with small amounts of colloidal silica (up to 2000 ppm). It has been found that the addition of SiO2 leads to a significant decrease of the shrinkage rate at the intermediate state of sintering due to the reduction of point defects (predominantly oxygen vacancies). Doping with small amounts of SiO2 results in heterogeneous microstructures in which abnormal grain growth was observed above a critical temperature of near 1600 °C. Below this temperature, silicon was detected at the grain-boundary triple junctions forming amorphous pockets and over 10 nm at each side of the grain boundaries. Above 1600 °C, a glassy phase of 2–3 nm in thickness was formed at the grain boundaries.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the European Ceramic Society - Volume 28, Issue 1, 2008, Pages 205–215
نویسندگان
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