Provided are pre-sintered and sintered zirconia dental ceramic materials. The materials have a gradient in yttria content. The materials may have a gradient in one or more physical/mechanical property and/or one or more optical property. The materials may be made by mixing at least two zirconia ceramic powders having different yttria content. A sintered zirconia dental ceramic material may be in the form of a dental article.

Disclosed is a polycrystalline ceramic dielectric comprising: crystal grain bulks made of a barium titanate-based ceramic; and grain boundaries comprising interfaces between the crystal grain bulks, wherein the composition of the grain boundaries is controlled using dopants. By controlling the grain boundary composition using dopants so that the dopants are distributed across a width of 5 nm or less and using a nano-sized, fine-grained barium titanate-based ceramic precursor, the grain boundary structure within the polycrystals may maintain electroneutrality, and their ferroelectricity may be controlled, thereby allowing for smoother polarization reaction. Accordingly, the present disclosure provides polycrystalline ceramic dielectrics that have dielectric properties such as high permittivity and low dielectric losses in a wide frequency range, a small amount of reduction in electric field-dependent relative permittivity, high temperature stability, non-reducibility under a reduction sintering condition, and resulting high insulation resistance, and a preparation method therefor.

Disclosed is a polycrystalline ceramic dielectric comprising: crystal grain bulks made of a barium titanate-based ceramic; and grain boundaries comprising interfaces between the crystal grain bulks, wherein the composition of the grain boundaries is controlled using dopants. By controlling the grain boundary composition using dopants so that the dopants are distributed across a width of 5 nm or less and using a nano-sized, fine-grained barium titanate-based ceramic precursor, the grain boundary structure within the polycrystals may maintain electroneutrality, and their ferroelectricity may be controlled, thereby allowing for smoother polarization reaction. Accordingly, the present disclosure provides polycrystalline ceramic dielectrics that have dielectric properties such as high permittivity and low dielectric losses in a wide frequency range, a small amount of reduction in electric field-dependent relative permittivity, high temperature stability, non-reducibility under a reduction sintering condition, and resulting high insulation resistance, and a preparation method therefor.

A method of preparing an ITO ceramic target includes that: In.sub.2O.sub.3 powder with mass fraction of 90˜97 and SnO.sub.2 powder with mass fraction of 10˜3 are ball-milled and mixed with deionized water, diluent, binder and polymer material by a sand mill to obtain an ITO ceramic slurry with a solid content between 70˜80% and a viscosity between 120˜300 mpa.Math.s, with an average particle size D50 of the mixed powder controlled at 100˜300 nm; the ITO ceramic slurry is shaped by a pressure grouting to obtain an ITO ceramic green body with a relative density of 58˜62%; the ITO ceramic green body is put into a degreasing and sintering integrated furnace, and under a degreasing temperature of 700˜800° C., the ITO ceramic target is degreased in an atmospheric oxygen atmosphere for the time set to 12˜36 hours; the temperature increases from the degreasing temperature to the first sintering temperature of 1,600˜1,650° C.

A method of preparing an ITO ceramic target includes that: In.sub.2O.sub.3 powder with mass fraction of 90˜97 and SnO.sub.2 powder with mass fraction of 10˜3 are ball-milled and mixed with deionized water, diluent, binder and polymer material by a sand mill to obtain an ITO ceramic slurry with a solid content between 70˜80% and a viscosity between 120˜300 mpa.Math.s, with an average particle size D50 of the mixed powder controlled at 100˜300 nm; the ITO ceramic slurry is shaped by a pressure grouting to obtain an ITO ceramic green body with a relative density of 58˜62%; the ITO ceramic green body is put into a degreasing and sintering integrated furnace, and under a degreasing temperature of 700˜800° C., the ITO ceramic target is degreased in an atmospheric oxygen atmosphere for the time set to 12˜36 hours; the temperature increases from the degreasing temperature to the first sintering temperature of 1,600˜1,650° C.

Compositions and methods for making biocompatible articles are provided. A method includes preparing a 3D printable mixture and depositing successive layers of the mixture in a predetermined pattern to form a porous biocompatible article. The predetermined pattern has a porosity suitable for a bone or cartilage scaffold. Associated 3D printable compositions and porous articles made from the described methods are also described. The preparing a 3D printable mixture can comprise conjugating an alkyne-terminated polymer to a peptide to form a peptide-containing composite, or providing a mixture that comprises a ceramic material and a binder, and wherein the 3D printable mixture comprises from 50 wt. % to 80 wt. % of the ceramic material.

Compositions and methods for making biocompatible articles are provided. A method includes preparing a 3D printable mixture and depositing successive layers of the mixture in a predetermined pattern to form a porous biocompatible article. The predetermined pattern has a porosity suitable for a bone or cartilage scaffold. Associated 3D printable compositions and porous articles made from the described methods are also described. The preparing a 3D printable mixture can comprise conjugating an alkyne-terminated polymer to a peptide to form a peptide-containing composite, or providing a mixture that comprises a ceramic material and a binder, and wherein the 3D printable mixture comprises from 50 wt. % to 80 wt. % of the ceramic material.

Provided are a high-entropy carbide ceramic, a rare earth-containing high-entropy carbide ceramic, fibers thereof, precursors thereof, and preparation methods thereof. The precursor includes at least four elements selected from Ti, Zr, Hf, V, Nb, Ta, Mo, and W, with each metal element accounting for 5-35% of the total molar quantity of metal elements in the precursor. The rare earth-containing high-entropy carbide ceramic precursor includes at least four transition metal elements and at least one rare-earth metal element. The high-entropy ceramic is a single-crystal-phase high-performance ceramic prepared from the precursor, with each element being homogenously distributed at molecular level. The method for preparing the high-entropy ceramic fiber includes uniformly mixing high-entropy carbide ceramic precursor containing target metal elements with spinning aid and solvent to prepare a spinnable precursor solution, followed by spinning, pyrolyzation, and high-temperature solid solution to prepare the high-entropy carbide ceramic fiber.

Provided are a high-entropy carbide ceramic, a rare earth-containing high-entropy carbide ceramic, fibers thereof, precursors thereof, and preparation methods thereof. The precursor includes at least four elements selected from Ti, Zr, Hf, V, Nb, Ta, Mo, and W, with each metal element accounting for 5-35% of the total molar quantity of metal elements in the precursor. The rare earth-containing high-entropy carbide ceramic precursor includes at least four transition metal elements and at least one rare-earth metal element. The high-entropy ceramic is a single-crystal-phase high-performance ceramic prepared from the precursor, with each element being homogenously distributed at molecular level. The method for preparing the high-entropy ceramic fiber includes uniformly mixing high-entropy carbide ceramic precursor containing target metal elements with spinning aid and solvent to prepare a spinnable precursor solution, followed by spinning, pyrolyzation, and high-temperature solid solution to prepare the high-entropy carbide ceramic fiber.

Provided is a boron nitride sintered body including boron nitride particles and pores, the boron nitride sintered body having a sheet shape and a thickness of less than 2 mm. Provided is a method for manufacturing a boron nitride sintered body, the method including a sintering step of molding and heating a blend containing a boron carbonitride powder and a sintering aid to obtain a sheet-shaped boron nitride sintered body including boron nitride particles and pores, in which a thickness of the boron nitride sintered body obtained in the sintering step is less than 2 mm.