Zirconia pre-sintered body
The present invention provides a pre-sintered body for obtaining a zirconia sintered body that can satisfy both high strength and high translucency, and a method of production of such a pre-sintered body. The present invention relates to a zirconia pre-sintered body comprising a secondary aggregate having an average particle diameter of 275 nm or less, the secondary aggregate comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia, the secondary aggregate comprising a larger particle having an average primary particle diameter of 100 nm or more and 200 nm or less, and a smaller particle having an average primary particle diameter of 10 nm or more and less than 60 nm.
1 . A zirconia pre-sintered body comprising a secondary aggregate having an average particle diameter of 275 nm or less,
the secondary aggregate comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia,
the secondary aggregate comprising a larger particle portion having an average primary particle diameter of 100 nm or more and 200 nm or less, and a smaller particle portion having an average primary particle diameter of 10 nm or more and less than 60 nm, and
the larger particle portion comprising zirconia, the stabilizer, or both and the smaller particle portion comprising zirconia, the stabilizer, or both,
wherein the content of the larger particle portion in the secondary aggregate is 15 to 85 volume %, and the content of the smaller particle portion in the secondary aggregate is 15 to 85 volume %.
2 . The zirconia pre-sintered body according to claim 1 , wherein the stabilizer is yttria.
3 . The zirconia pre-sintered body according to claim 1 , wherein the content of the stabilizer is 3.0 to 7.5 mol % with respect to the total mole of the zirconia and the stabilizer, and at least a part of the stabilizer is not dissolved in the zirconia as a solid solution.
4 . The zirconia pre-sintered body according to claim 1 , which has a density of 2.75 g/cm 3 or more.
5 . The zirconia pre-sintered body according to claim 1 , wherein a sintered body after the pre-sintered body is fired at a firing temperature of 1,500° C. or less for 2 hours contains crystal grains with an average crystal grain size of 0.70 μm or less.
6 . The zirconia pre-sintered body according to claim 1 , wherein a sintered body after the pre-sintered body is fired at a firing temperature of 1,500° C. or less for 2 hours has a density of 5.8 g/cm 3 or more.
7 . The zirconia pre-sintered body according to claim 1 , which has two peaks in a number-based particle size distribution measured with an electron microscope image of the larger particle portion and the smaller particle portion, with a first peak representing a most frequent particle diameter occurring at a particle size of 10 nm or more and less than 60 nm, and a second peak occurring at a particle size of 60 nm or more and 200 nm or less.
8 . A method for producing a zirconia pre-sintered body that comprises zirconia, and a stabilizer capable of preventing a phase transformation of zirconia, comprising sintering a composition which comprises a powder (A) that comprises a secondary aggregate comprising a powder (a1) having an average primary particle diameter of 100 nm or more and 200 nm or less, and a powder (a2) having an average primary particle diameter of 10 nm or more and less than 60 nm,
the secondary aggregate having an average particle diameter of 275 nm or less,
the secondary aggregate comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia,
wherein the powder (A) comprising the secondary aggregate comprises:
15 to 85 mass % of the powder (a1) having an average primary particle diameter of 100 nm or more and 200 nm or less; and
15 to 85 mass % of the powder (a2) having an average primary particle diameter of 10 nm or more and less than 60 nm.
9 . The method for producing a zirconia pre-sintered body according to claim 8 , wherein the powder (a1) comprises the stabilizer.
10 . The method for producing a zirconia pre-sintered body according to claim 8 , wherein the content of the stabilizer is 3.0 to 7.5 mol % with respect to the total mole of the zirconia and the stabilizer, and at least a part of the stabilizer is not dissolved in the zirconia as a solid solution.
11 . The method for producing a zirconia pre-sintered body according to claim 8 , wherein the stabilizer is yttria.
12 . A method for producing a powder for obtaining a zirconia pre-sintered body of claim 1 , comprising
producing a slurry comprising a secondary aggregate that comprises a powder (a1) having an average primary particle diameter of 100 to 275 nm, and a powder (a2) having an average primary particle diameter of 10 nm or more and less than 60 nm, and that has an average particle diameter of 275 nm or less; and
granulating the slurry by dry spraying.
13 . A method for producing a zirconia sintered body, comprising firing a zirconia pre-sintered body of claim 1 .