کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1462002 989625 2012 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of pre-oxidation on the microstructure, mechanical and dielectric properties of highly porous silicon nitride ceramics
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Effect of pre-oxidation on the microstructure, mechanical and dielectric properties of highly porous silicon nitride ceramics
چکیده انگلیسی

Highly porous Si3N4 ceramics have been fabricated via freeze casting and sintering. The as-sintered samples were pre-oxidized at 1200–1400 °C for 15 min. The effect of pre-oxidation temperature on the microstructure, flexural strength, and dielectric properties of porous Si3N4 ceramics were investigated. As the pre-oxidation temperature increased from 1200 °C to 1400 °C, firstly, the flexural strength of the pre-oxidized specimens remained almost constant at 1200 °C, and then decreased to 14.2 MPa at 1300 °C, but finally increased to 25.6 MPa at 1400 °C, while the dielectric constant decreased gradually over the frequencies ranging from 8.2 GHz to 12.4 GHz. This simple process allows porous Si3N4 ceramics to have ultra-low dielectric constant and moderate strength, which will be feasible in broadband radome applications at high temperatures.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 38, Issue 7, September 2012, Pages 6021–6026
نویسندگان
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