Other

Acucera Inc.

Vatechacucera, Inc.

Dae-Joon Kim

Sang Wook Kim

Hyung-Jin Jung

Seung Won Seo

Ju-Woong Jang

Yong Hwan Jeong

Provided is a machinable zirconia having high translucency as a sintered body which is formed to include a tetragonal zirconia composite powder containing 79.8 to 92 mol % ZrO, 4.5 to 10.2 mol % YO, 3.5 to 7.5 mol % NbOor 5.5 to 10.0 mol % TaO, and a TiOnano powder which is added with a weight ratio of more than 0 wt % and up to 2.5 wt % to the composite powder, wherein a density of the sintered body is 99% or more, an average grain size of the sintered body is 2 &#x3bc;m or larger, hardness of the sintered body is in a range of 4 to 10 GPa, fracture toughness of the sintered body is in a range of 9 to 14 MPa&#xb7;m, a strength of the sintered body is in a range of 400 to 1000 MPa.

Machinable zirconia comprising titania nanopowder

A method for the preparation of tetragonal zirconia polycrystal composite with high toughness and low-temperature degradation resistance. The method comprising adding transformable TZP of ZrO.sub.2 --Y.sub.2 O.sub.3 --Nb.sub.2 O.sub.5 /Ta.sub.2 O.sub.5 system to non-transformable TZP of ZrO.sub.2 --Y.sub.2 O.sub.3 --Nb.sub.2 O.sub.5 /Ta.sub.2 O.sub.5 system in an amount of not more than 60% by weight based on the total weight of the resulting mixture; and sintering the mixture at above 1,500.degree. C. Even though being exposed to a temperature ranging from 100.degree. to 400.degree. C. for a long time in air, the TZP composite prepared by the present method is rarely transformed into monoclinic zirconia and yet exhibits high toughness.

Methods for preparation of tetragonal zirconia polycrystal composites

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Seoul, South Korea

Dae-Joon Kim