Low-Temperature Processing and Mechanical Properties of Zirconia and Zirconia–Alumina Nanoceramics |
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Authors: | Oleg Vasylkiv Yoshio Sakka Valeriy V Skorokhod |
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Affiliation: | National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki, 305-0047, Japan;Institute for Materials Science, National Academy of Science of the Ukraine, Kiev, 03680, Ukraine |
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Abstract: | The 1.5- to 3-mol%-Y2O3-stabilized tetragonal ZrO2 (Y-TZP) and Al2O3/Y-TZP nanocomposite ceramics with 1 to 5 wt% of alumina were produced by a colloidal technique and low-temperature sintering. The influence of the ceramic processing conditions, resulting density, microstructure, and the alumina content on the hardness and toughness were determined. The densification of the zirconia (Y-TZP) ceramic at low temperatures was possible only when a highly uniform packing of the nanoaggregates was achieved in the green compacts. The bulk nanostructured 3-mol%-yttria-stabilized zirconia ceramic with an average grain size of 112 nm was shown to reach a hardness of 12.2 GPa and a fracture toughness of 9.3 MPa·m1/2. The addition of alumina allowed the sintering process to be intensified. A nanograined bulk alumina/zirconia composite ceramic with an average grain size of 94 nm was obtained, and the hardness increased to 16.2 GPa. Nanograined tetragonal zirconia ceramics with a reduced yttria-stabilizer content were shown to reach fracture toughnesses between 12.6–14.8 MPa·m1/2 (2Y-TZP) and 11.9–13.9 MPa·m1/2 (1.5Y-TZP). |
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Keywords: | hardness zirconia nanomaterials |
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