Continuous and symmetric graded Si3N4 ceramics designed by spark plasma sintering at 15 MPa. Issue 13 (September 2019)

• Record Type: Journal Article
• Authors: Yu, Jun-Jie; Sun, Shi-Kuan; Wei, Wan-Xin; Guo, Wei-Ming; Plucknett, Kevin; Lin, Hua-Tay
• Is Part Of: Ceramics international. Volume 45:Issue 13(2019)
• Page Start: 16703
• Page End: 16706
• Publication Date: 2019-09
• Subjects: Si3N4 -- Continuous graded ceramics -- Sintering -- Microstructure -- Mechanical properties; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2019.05.148
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Continuous and symmetric graded Si3 N4 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 Si3 N4 specimen prepared under 15 MPa, owing to the ratio variation of α-/β -Si3 N4 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∙m 1/2 to 5.6 MPa∙m 1/2 .