[Problem]

A technique for improving translucency in order to prepare a zirconia sintered body having high translucency without using special equipment, has been required.

[Solution]

To provide A sintering method for a dental zirconia calcined body containing 5.5 mol % to 7.0 mol % of a stabilizer, wherein the method satisfies the following (a) to (c). (a) an average rate of temperature increase in the section from room temperature to 1300° C. is 9° C./min or more. (b) an average rate of temperature increase in the section from 1300° C. to 1400° C. is 0.6° C./min or more and 3° C./min or less. (c) an average rate of temperature increase in the section from 1400° C. to the maximum temperature of the sintering process is 0.5° C./min or more and 2.5° C./min or less.

A zirconia sintered body is provided and includes yttria and zirconia, containing yttria by a content ranging from 4.5 mol % or more to 6.5 mol % or less and zirconia as the remainder, the total light transmittance of a 1-mm thick sample measured in compliance with JIS K 7361-1 being 46.5% or higher, the three-point bending strength being 700 MPa or higher, and a ratio of an integrated value for the total light transmittance to an integrated value for the parallel light transmittance of a 1-mm thick sample measured at the measurement wavelength ranging from 400 to 700 nm being 1.3% or less.

A sintered bead with the following crystal phases, in percentages by mass based on crystal phases: 25%≤zircon, or “Z.sub.1”, ≤94%; 4%≤stabilized zirconia+stabilized hafnia, or “Z.sub.2”, ≤61%; monoclinic zirconia+monoclinic hafnia, or “Z.sub.3”≤50%; corundum≤57%; crystal phases other than Z.sub.1, Z.sub.2, Z.sub.3 and corundum<10%; the following chemical composition, in percentages by mass based on oxides: 33%≤ZrO.sub.2+HfO.sub.2, or “Z.sub.4”≤83.4%; HfO.sub.2≤2%; 10.6%≤SiO.sub.2≤34.7%; Al.sub.2O.sub.3≤50%; 0%≤Y.sub.2O.sub.3, or “Z.sub.5”; 0%≤CeO.sub.2, or “Z.sub.6”; 0.3%≤CeO.sub.2+Y.sub.2O.sub.3≤19%, provided that (1) CeO.sub.2+3.76*Y.sub.2O.sub.3≥0.128*Z, and (2) CeO.sub.2+1.3*Y.sub.2O.sub.3≤0.318*Z, with Z=Z.sub.4+Z.sub.5+Z.sub.6−(0.67*Z.sub.1*(Z.sub.4+Z.sub.5+Z.sub.6)/(0.67*Z.sub.1+Z.sub.2+Z.sub.3)); MgO≤5%; CaO≤2%; oxides other than ZrO.sub.2, HfO.sub.2, SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, CeO.sub.2 and Y.sub.2O.sub.3<5.0%.

A manufacturing method of a sintered body is a manufacturing method of the sintered body which increases a temperature while applying an electric field to a ceramic compact. This method controls a current which flows to the ceramic compact so that a sintering rate becomes constant.

A coated substrate has a substrate and a coating system having one or more ceramic layers. At least a first layer of one of the one or more ceramic layers is a columnar layer having as-deposited columns and intercolumn gaps. The intercolumn gaps have a mean width at least one of: at least 4.0 micrometers; and at least 1.5% of a thickness of said first layer.

A zirconia sintered body comprises zirconia and multiple different areas, including at least one upper area and at least one lower area having a different chemical composition and a different strength. The sintered body has a translucency and a strength with an inverse relationship. The translucency increases in one direction across the multiple different areas and the strength decreasing in the same direction across the multiple different areas. At least part of the sintered body has a total light transmittance of at least 35% and less than 53% to light with a wavelength at least at a point between 400 nm and 600 nm, and at least 51% and less than 57% to light with a wavelength at least at a point between 600 nm and 800 nm, at a thickness of 0.6 mm. At least a part of the sintered body has a strength of at least 925 Mpa.

Disclosed is a curable composition for the manufacture, by stereolithography, of a green part made of a ceramic or metallic material, the curable composition including at least one ceramic and/or metallic powder; at least one polymerizable monomer and/or oligomer; at least one initiator for the polymerization of the polymerizable monomer(s) and/or oligomer(s). The initiator(s) are selected from iodonium, sulphonium and diazonium salts and onium salts in combination with at least one amine and/or at least one phosphine to form a charge transfer complex. The initiator(s) may generate the initiation of a thermal polymerization under the exposure to at least one source of UV, visible or IR irradiation.

A sintered body that includes zirconia containing a stabilizing element; and a plastic deformation region, wherein the stabilizing element includes at least one rare-earth element other than yttrium, and the stabilizing element content is 1.5% or more by mole and less than 3.0% by mole.

The invention relates to a process for fabricating complex mechanical shapes from metal or ceramic, and in particular to fabricating complex mechanical shapes using a pressure-assisted sintering technique to address problems relating to variations in specimen thickness and tooling, or densification gradients, by 3-D printing of a sacrificial, self-destructing powder mold is created using e.g. alumina and swellable binders such as polysaccharides. The binder-free sintering powder that forms the manufactured item is injected into the mold, and high pressure is applied. The powder assembly can then be sintered by any pressure assisted technique to full densification and the self-destructing mold allows the release of the fully densified complex manufactured item.

A method of selectively removing at least part of a first phase from a surface of a nanocomposite includes at least a first phase and a second phase, each phase having a respective threshold fluence under a given number of applied laser pulses for removal of the phase by laser ablation. The threshold fluence of the first phase is less than the threshold fluence of the second phase. The method includes irradiating the surface of the nanocomposite with a laser beam having a laser beam diameter, a laser pulse duration, and a laser pulse energy during the irradiation. The laser fluence during the irradiation is less than the threshold fluence of the second phase and greater than the threshold fluence of the first phase. The laser beam diameter is greater than an average grain size of the first phase at the surface of the nanocomposite.