X-ray diffraction and atomic force microscopy study in aged zirconia-toughened alumina composite with dispersion of m-Zr02 nanoparticles

摘要

X-ray diffraction (XRD) and atomic force microscopy (AFM) were utilized to investigate the aging behavior of pressureless sintered monolithic ZrO_2 (TZ-3Y) and zirconia-toughened alumina composite with additions of 2 wt% m-ZrO_2 nanoparticles at 1520 °C for 1 h. Results show that TZ-3Y exhibited significant aging in water steam at 134 °C under pressure 2 bar compared to zirconia toughened alumina (ZTA) composite. The maximum fraction of monoclinic polymorph resulted after 10 and 15 h of aging for monolithic TZ-3Y (~85%) and ZTA (-2.3%) composite, respectively. The homogeneous dispersion of zirconia into the matrix and its fine grain size as well as the high Young's modulus of the A1_2O_3 matrix which can provide a constraining effect on the zirconia could partially inhibit the phase transformation. In terms of monoclinic phase content, our ZTA composite fulfil ISO 1336-2008 requirements for implants for surgery, being thus an interesting alternative in this field.