Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Microstructure and properties of porous silicon nitride ceramics prepared by gel-casting and gas pressure sintering
Highlights ► Gel-casting and GPS is an effective way to prepare porous Si3N4 ceramics. ► Porosity and microstructure are largely dependent on the solid loadings. ► Porous Si3N4 ceramics have desirable mechanical properties. ► Porous Si3N4 ceramics have suitable dielectric properties.
Abstract Wave-transparent porous Si3N4 ceramics were prepared by gel-casting and gas pressure sintering, and the effects of solid loading on microstructure, mechanical and dielectric properties were investigated. Microstructures with interlocked elongated β-Si3N4 grains and uniformly distributed pores were observed, while both the β-Si3N4 phase content and grain aspect ratio reduced as the solid loading increased due to the restrained anisotropic growth of β-Si3N4 grains. As the solid loading increased from 30 to 45vol.%, the porosity of ceramics declined from 57.6% to 36.4%. The flexural strength increased linearly from 108.3 to 235.1MPa, and the dielectric constant and loss tangent of ceramics increased from 2.63 and 2.85×10−3 to 3.68 and 3.56×10−3 (10GHz), respectively.
Microstructure and properties of porous silicon nitride ceramics prepared by gel-casting and gas pressure sintering
Highlights ► Gel-casting and GPS is an effective way to prepare porous Si3N4 ceramics. ► Porosity and microstructure are largely dependent on the solid loadings. ► Porous Si3N4 ceramics have desirable mechanical properties. ► Porous Si3N4 ceramics have suitable dielectric properties.
Abstract Wave-transparent porous Si3N4 ceramics were prepared by gel-casting and gas pressure sintering, and the effects of solid loading on microstructure, mechanical and dielectric properties were investigated. Microstructures with interlocked elongated β-Si3N4 grains and uniformly distributed pores were observed, while both the β-Si3N4 phase content and grain aspect ratio reduced as the solid loading increased due to the restrained anisotropic growth of β-Si3N4 grains. As the solid loading increased from 30 to 45vol.%, the porosity of ceramics declined from 57.6% to 36.4%. The flexural strength increased linearly from 108.3 to 235.1MPa, and the dielectric constant and loss tangent of ceramics increased from 2.63 and 2.85×10−3 to 3.68 and 3.56×10−3 (10GHz), respectively.
Microstructure and properties of porous silicon nitride ceramics prepared by gel-casting and gas pressure sintering
Zou, Chunrong (Autor:in) / Zhang, Changrui (Autor:in) / Li, Bin (Autor:in) / Wang, Siqing (Autor:in) / Cao, Feng (Autor:in)
27.07.2012
5 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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