Toughened ZrO2 ceramics sintered with a La2O3-rich glass as additive

✍ Scribed by C. Santos; R.C. Souza; N. Almeida; F.A. Almeida; R.R.F. Silva; M.H.F.V. Fernandes

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 932 KB
• Volume: 200
• Category: Article
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2007.08.061

✦ Synopsis

In this study, the influence of the glass addition and sintering parameters on the densification and mechanical properties of tetragonal zirconia polycrystals (3Y-TZP) ceramics were evaluated. High-purity tetragonal ZrO 2 powder and La 2 O 3 -rich glass were used as starting powders. Two compositions based on ZrO 2 and containing 5 wt.% and 10 wt.% of La 2 O 3rich glass were studied in this work. The starting powders were mixed/milled by planetary milling, dried at 90 • C for 24 h, sieved through a 60 mesh screen and uniaxially cold pressed under 80 MPa. The samples were sintered in air at 1200 • C, 1300 • C, 1400 • C for 60 min and at 1450 • C for 120 min, with heating and cooling rates of 10 • C/min. Sintered samples were characterized by relative density, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Hardness and fracture toughness were obtained by Vickers indentation method.

Dense sintered samples were obtained for all conditions. Furthermore, only tetragonal-ZrO 2 was identified as crystalline phase in sintered samples, independently of the conditions studied. Samples sintered at 1300 • C for 60 min presented the optimal mechanical properties with hardness and fracture toughness values near to 12 GPa and 8.5 MPa m 1/2 , respectively.