Effect of cooling rate on the microstructural and mechanical properties of speed-sintered monolithic zirconia

Korte inhoud:Objectives To evaluate the effect of different speed-sintering cooling rates on the phase composition, microstructure, optical and mechanical properties of monolithic zirconia. Methods Speed-sintered ZirCAD LT (Ivoclar) (LT_1200; 5 min at 1480 °C; oven-door opening and air-cooling: 1200 °C) and Katana STML (Kuraray Noritake) (STML_800; 30 min at 1560 °C; oven-door opening and air-cooling: 800 °C) were compared to speed-sintered ZirCAD LT and Katana STML with a steady cooling rate and oven-door opening at 300 °C (LT_300 and STML_300, respectively). Density was measured by Archimedes’ principle; composition by XRF; phase by XRD; grain size by SEM; translucency parameter by spectrophotometry. Vickers hardness, indentation fracture toughness, and biaxial strength were also assessed. Results Regardless of the cooling rate, ZirCAD LT and Katana STML revealed similar density, chemical composition and grain size. Both 3Y-TZP ZirCAD LT_1200/300 zirconia had lower cubic ZrO2-phase content, and lower Y2O3 content in the remaining tetragonal ZrO2 phases compared to 5Y-PSZ Katana STML_800/300 zirconia. In contrast to 3Y-TZP, 5Y-PSZ contained a high amount of metastable t’-phase. TP of ZirCAD LT and Katana STML were not affected by the cooling rate. The hardness and fracture toughness of both 3Y-TZP and 5Y-PSZ were not influenced by cooling rate variations. Steady cooling significantly diminished flexural strength and mechanical reliability of Katana STML_300, while it did not have any effect on the ZirCAD LT zirconia grades. Significance Steady cooling during speed-sintering did not significantly influence the performance of 3Y-TZP but can negatively influence flexural strength and mechanical reliability of 5Y-PSZ zirconia ceramics.

Jaar van publicatie:2025

Trefwoorden:Biomaterialen en biomedische ingenieurswetenschappen, Tandheelkunde

Toegankelijkheid:Embargoed

Reviewstatus:Peerreview