Effects of Sr2Nb2O7 additive on microstructure and mechanical properties of 3Y–TZP/Al2O3 ceramics
2002; Elsevier BV; Volume: 28; Issue: 2 Linguagem: Inglês
10.1016/s0272-8842(01)00079-7
ISSN1873-3956
Autores Tópico(s)Nuclear materials and radiation effects
ResumoAbstract The effects of Sr 2 Nb 2 O 7 additive on microstructure and mechanical properties of 3Y–TZP/Al 2 O 3 ceramics were investigated. Sr 2 Nb 2 O 7 reacted with Al 2 O 3 to form SrAl 12 O 19 platelets, which could contribute to the fracture toughness due to the elongated grains. The fraction of transformable tetragonal zirconia phase increased firstly with the Sr 2 Nb 2 O 7 content and then decreased when the additive content is beyond a critical value. Also, the fracture toughness increased firstly to a maximum value (10.2 MPa.m 1/2 ) with the additive content and then decreased for composites sintered at 1600 °C for 6 h, while it increased linearly with additive content for composites sintered at 1575 °C for 6 h. However, the Vickers hardness decreased linearly with the Sr 2 Nb 2 O 7 content for composites sintered under any condition investigated here. The fracture toughness was affected by the fraction of transformable tetragonal zirconia phase and Sr 2 Nb 2 O 7 content, and the toughening effects should be the integrated result of stress-induced transformation toughening and elongated grain toughening.
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