Continuous and symmetric graded Si3N4 ceramics designed by spark plasma sintering at 15 MPa

Continuous and symmetric graded Si3N4 ceramics with hard surface and tough core were fabricated by spark plasma sintering at 1800 °C under low pressure. The results of phase assemblage, microstructure, Vickers hardness and fracture toughness revealed that the mechanical properties strongly depended...

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Bibliographic Details
Published inCeramics international Vol. 45; no. 13; pp. 16703 - 16706
Main Authors Yu, Jun-Jie, Sun, Shi-Kuan, Wei, Wan-Xin, Guo, Wei-Ming, Plucknett, Kevin, Lin, Hua-Tay
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.09.2019
Subjects
Continuous graded ceramics
Mechanical properties
Microstructure
Si3N4
Sintering
Mechanical properties
Si3N4
Microstructure
Continuous graded ceramics
Sintering
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Summary:Continuous and symmetric graded Si3N4 ceramics with hard surface and tough core were fabricated by spark plasma sintering at 1800 °C under low pressure. The results of phase assemblage, microstructure, Vickers hardness and fracture toughness revealed that the mechanical properties strongly depended on the external pressure and sampling position. For Si3N4 specimen prepared under 15 MPa, owing to the ratio variation of α-/β-Si3N4 phase and the increasing amount of elongated grain along the radial direction, the corresponding Vickers hardness from the edge to the center gradually decreased from 20.6 GPa to 18.5 GPa, and the fracture toughness increased from 4.0 MPa∙m1/2 to 5.6 MPa∙m1/2.
ISSN:0272-8842
1873-3956
DOI:10.1016/j.ceramint.2019.05.148