New ZrO2/Al2O3 Nanocomposite Fabricated from Hybrid Nanoparticles Prepared by CO2 Laser Co-Vaporization

Abstract

Alumina toughened zirconia (ATZ) and zirconia toughened alumina (ZTA) are currently the materials of choice to meet the need for tough, strong, and bioinert ceramics for medical devices. However, the mechanical properties of ZrO2/Al2O3 dispersion ceramics could be considerably increased by reducing the corresponding grain sizes and by improving the homogeneity of the phase dispersion. Here, we prepare nanoparticles with an intraparticular phase distribution of Zr(1−x)AlxO(2−x/2) and (γ-, δ-)Al2O3 by the simultaneous gas phase condensation of laser co-vaporized zirconia and alumina raw powders. During subsequent spark plasma sintering the zirconia defect structures and transition alumina phases transform to a homogeneously distributed dispersion of tetragonal ZrO2 (52.4 vol%) and α-Al2O3 (47.6 vol%). Ceramics sintered by spark plasma sintering are completely dense with average grain sizes in the range around 250 nm. Outstanding mechanical properties (flexural strength σf = 1500 MPa, fracture toughness KIc = 6.8 MPa m1/2) together with a high resistance against low temperature degradation make these materials promising candidates for next generation bioceramics in total hip replacements and for dental implants.

Design of a New Zirconia–Alumina–Ta Micro‐Nanocomposite with Unique Mechanical Properties

“…Analyses of the post mortem fracture surfaces reveal that failure mechanism was complete or partial plastic deformation and debonding of lamellar tantalum particles. In Table mechanical properties of the new 2Y‐TZP/Al 2 O 3 ‐Ta ceramic–metal composite are compared to those of 2Y‐TZP and 2Y‐TZP/Al 2 O 3 ceramics obtained in earlier studies. Maximum flexural strength and Vickers hardness were obtained for the zirconia–alumina composite.…”

“…Starting from this mixture, a 2Y‐TZP/Al 2 O 3 hybrid nanopowder consisting of 47.6 vol% (37.4 mass%) Al 2 O 3 and 52.4 vol% (62.6 mass%) ZrO 2 was prepared by using the CoLAVA method. Details of the preparation were reported elsewhere . The Ta powder was attrition milled with zirconia balls in a teflon container for 4 h using isopropyl alcohol as fluid.…”

“…To fabricate the ceramic 2Y‐TZP/Al 2 O 3 matrix reinforced with lamellar Ta particles, the CoLAVA nanopowder was wet mixed with 20 vol% of the ball‐milled Ta powder and subsequently compacted by using SPS at 1400°C and 80 MPa under vacuum. Details of the ceramic/metal suspension processing and sintering parameters were reported elsewhere . The sintered specimens had diameters of 20 and 50 mm and a thickness of 2–4 mm.…”

“…Based on our previous research, the CO 2 laser covaporization (CoLAVA) method was chosen for the preparation of a zirconia–alumina hybrid nanopowder to avoid an inhomogeneous distribution of both phases . Nevertheless, the resulting ceramic materials remain brittle.…”

Europium(III)‐Doped MgAl2O4 Spinel Nanophosphor Prepared by CO2 Laser Co‐Vaporization

“…The CO 2 laser vaporization technique has proven its versatility to prepare a broad range of functional, single or multiphase ceramic NPs with excellent properties . Briefly, a CO 2 laser beam is focused onto the surface of a coarse‐grained raw powder.…”