Zirconia composition, zirconia pre-sintered body, and zirconia sintered body, and methods of production of zirconia pre-sintered body and zirconia sintered body

5:

• A zirconia pre-sintered body comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia, wherein:
• at least a part of the stabilizer is not dissolved in zirconia as a solid solution,
• the monoclinic crystal fraction fm represented by the mathematical formula (1) below is 50 to 98%, and
• the stabilizer has a local abundance of 10 to 90 mol % in particles derived from the stabilizer,
• f
• m
• =
• I
• 28
• /
• (
• I
• 28
• +
• I
• 30
• )
• *
• ⁢
• 100
• ,
• (
• 1
• )
• wherein fm represents the fraction (%) of the monoclinic crystal system, I28 represents the area intensity of a peak near 2θ=28°, where the main peak of the monoclinic crystal system appears in XRD measurement, and I30 represents the area intensity of a peak near 2θ=30°, where the main peak of the tetragonal or cubic crystal system appears in XRD measurement.

8:

• The zirconia pre-sintered body according to claim 5, which has an OP value of less than 15 in a sintered body of 1.2 mm thickness after 120 minutes of sintering at 900 to 1,400° C., as calculated from the following mathematical formula (2),
• OP
• ⁢
• value
• =
• (
• a
• *
• transmission
• -
• a
• *
• reflection
• )
• 2
• +
• (
• b
• *
• transmission
• -
• b
• *
• reflection
• )
• 2
• (
• 2
• )
• wherein a*transmission and b*transmission represent the color coordinates of L*a*b* color system for transmitted light, and a*reflection and b*reflection represent the color coordinates of L*a*b* color system for reflected light.

11:

• The zirconia pre-sintered body according to claim 5, wherein a first translucency ΔL1*(W−B) of a first sintered body fabricated by 120 minutes of sintering at 1,300° C., and a second translucency ΔL2*(W−B) of a second sintered body fabricated by 10 minutes of sintering at 1,300° C. satisfy the relationship of the following mathematical formula (3),
• Δ
• ⁢
• L
• 2
• *
• (
• W
• -
• B
• )
• /
• Δ
• ⁢
• L
• 1
• *
• (
• W
• -
• B
• )
• ≥
• 0.85
• .
• (
• 3
• )

13:

• A zirconia sintered body comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia, wherein:
• the zirconia sintered body has a stabilizer content of 2 to 9 mol % relative to the total mole of the zirconia and the stabilizer, and has a ΔL*(W−B) of 5 or more, and an OP value of less than 15, as calculated from the following mathematical formula (2), in a sintered body of 1.2 mm thickness,
• OP
• ⁢
• value
• =
• (
• a
• *
• transmission
• -
• a
• *
• reflection
• )
• 2
• +
• (
• b
• *
• transmission
• -
• b
• *
• reflection
• )
• 2
• (
• 2
• )
• wherein a*transmission and b*transmission represent the color coordinates of L*a*b* color system for transmitted light, and a*reflection and b*reflection represent the color coordinates of L*a*b* color system for reflected light.