121 results about "Tetragonal zirconia" patented technology

A corrosion resistant component of semiconductor processing equipment such as a plasma chamber comprises zirconia toughened ceramic material as an outermost surface of the component. The component can be made entirely of the ceramic material or the ceramic material can be provided as a coating on a substrate such as aluminum or aluminum alloy, stainless steel, or refractory metal. The zirconia toughened ceramic can be tetragonal zirconia polycrystalline (TZP) material, partially-stabilized zirconia (PSZ), or a zirconia dispersion toughened ceramic (ZTC) such as zirconia-toughened alumina (tetragonal zirconia particles dispersed in Al2O3). In the case of a ceramic zirconia toughened coating, one or more intermediate layers may be provided between the component and the ceramic coating. To promote adhesion of the ceramic coating, the component surface or the intermediate layer surface may be subjected to a surface roughening treatment prior to depositing the ceramic coating.

The invention relates to a porous dental milling block comprising at least two geometrically defined Material Sections A and B, Material Section A comprising a tetragonal zirconia crystal phase in an amount A-T in % and a cubic zirconia crystal phase in an amount A-C in %, Material Section B comprising cubic zirconia crystal phase in an amount B-T in % and cubic zirconia crystal phase in an amount B-C in %, wherein (amount of tetragonal phase A-T in %)/(amount of cubic phase content A-C in %)>1 and (amount of tetragonal phase content B-T in %)/(amount of cubic phase content B-C in %)<1. The invention also relates to a process of production of the porous dental milling block and its use for producing a dental article.

The invention relates to a dental prosthesis of zirconia material with tetragonal nanometer-sized ZrO2-CaO powder and much added amount of alumina. Said invention also relates to tooth body and false tooth prepared by said above tetragonal nanometer-sized ZrO2-CaO powder and zirconia material for prosthesis, so that making color transparency L*=64-81,colority a*=-1.04- 5.63 and b*=6.95-21.88,thus natural color.

A zirconia-containing composition and processes for synthesizing same. The composition comprises least about 99.9 percent tetragonal phase zirconia, based on the total crystalline zirconia in the zirconia-containing composition as determined by x-ray diffraction (XRD). The composition also has a substantially spherical morphology and comprises less than 100 wppm chlorine, based on the total weight of the zirconia-containing composition. The zirconia-containing composition has an average surface area of at least 80 m²/g and an average particle size of less than about 10 microns.

The invention discloses a colored zirconia ceramic, which is composed of tetragonal phase zirconia serving as the main crystalline phase and cubic phase zirconia serving as a minor crystalline phase, or is composed of tetragonal phase zirconia serving as the main crystalline phase, cubic phase zirconia serving as a minor crystalline phase, and a transition metal oxide. The colored zirconia ceramic realizes coloring through a rare earth metal that is in a solid solution state in cubic phase zirconia crystal grains, or achieves coloring through a rare earth metal that is in a solid solution state in cubic phase zirconia crystal grains, and is assisted by the transition metal oxide provided transition metal for toning. According to the invention, coloring rare earth metal ions are in a solid solution state in cubic zirconia lattices, and have no influence to the stability of tetragonal zirconia; solid solution rare earth metal ions in cubic zirconia are mainly adopted for coloring, then the consumption of other transition metal oxide coloring materials can be reduced or even the coloring materials can be not used, thus reducing the influence of transition metal oxide coloring materials concentrated at crystal boundaries to sintering densification, and avoiding the adverse effect on material strength.

This invention discloses a process for preparing zirconium oxide-aluminum oxide biphase gradient ceramic coating on the surface of zirconium-based material. The process comprises: preparing an electrolyte, supplying zirconium or zirconium alloy as the anode and metal stainless steel as the cathode (spacing = 8-12 cm), and performing micro-arc oxidation treatment on zirconium or zirconium alloy at an electrolyte temperature of 15-40 deg.C, a constant voltage (supplied from an impulse power supply) of 300-650 V, an initial current density of 6-20 A/mm2, a frequency of 50-1000 Hz, and a duty ratio of 5-40% for 25-90 min to obtain the product. The zirconium oxide-aluminum oxide biphase gradient ceramic coating is composed of t-ZrO2 and alpha-Al2O3 biphase, and the content of alpha-Al2O3 biphase is decreased from the surface to the matrix. The zirconium oxide-aluminum oxide biphase gradient ceramic coating has a nanoporous structure and no interface with the matrix, and thus has high combination strength and high hardness (above 1200 Hv).

The invention relates to a zirconia ceramic matrix composite and a preparation method thereof. In the composite, tetragonal zirconia is used as a substrate, and a Nb-Ti-Cr phase is used as a toughening phase, wherein the substrate and the toughening phase account for 20 and 80 volume percent of the total volume of the composite respectively and a sum of the volume percentages of the substrate and the toughening phase is 100 percent. Nb powder, Ti powder and Cr powder are mixed according to the mass ratio of Nb atoms to Ti atoms to Cr atoms of 50:37:23. The preparation method of the zirconia ceramic matrix composite comprises the following steps: ball milling the substrate and the toughening phase and mixing the mixture obtained after ball milling; and preparing the zirconia ceramic matrix composite by hot pressed sintering the mixture under vacuum. The composite of the invention has excellent high-temperature mechanical property and antioxygenic property as well as low cost; and compared with fiber and whisker toughened ceramic, the zirconia ceramic matrix composite has a similar toughening effect, but has simple preparation process, low cost and far more excellent conductivity.

Disclosed are a block having a structure for joining an abutment and a superstructure for a dental implant and a method for manufacturing the same. An abutment and a superstructure are not shaped in advance, and instead, a block, in which a structure for joining a fixture and other connection parts of a dental prosthesis are formed, is manufactured such that the block can be machined through CAD/CAM, or, after a wax mock-up or a resin mock-up is scanned and drawn on a paper, the block can be machined through CAM to form an abutment or the crown of a superstructure. In order to provide high strength and high toughness, the block is made of a stabilized tetragonal zirconia polycrystalline (TZP)-based material or a composite of zirconia and oxide. The method comprises the steps of pressing a starting material for a block, machining a resultant formation, and sintering the machined formation.

A method for forming a zirconium oxide (ZrO₂) layer on a substrate in a chamber includes controlling a temperature of the substrate; and repeating a unit cycle of an atomic layer deposition (ALD) method. The unit cycle includes supplying a zirconium (Zr) source into a chamber, parts of the Zr source being adsorbed into a surface of the substrate; purging non-adsorbed parts of the Zr source remaining inside the chamber; supplying a reaction gas for reacting with the adsorbed parts of the Zr source; and purging non-reacted parts of the reaction gas remaining inside the chamber and reaction byproducts, wherein the temperature of the substrate and a concentration of the reaction gas are controlled such that the ZrO₂ layer is formed with a tetragonal structure.

The invention discloses a process for preparing zirconium surface porous nanometer zirconia biological activity coat. The porous nanometer zirconia biological activity coat is directly produced by micro-arc oxidation treating zirconium and zirconium alloy under high pressure using impulsing power source, with water solution containing calcium and phosphorous as electrolytic solution. The produced nanometer zirconia biological activity coat comprises tetragonal zirconia with the thickness of more than 40 mum and porous nanometer crystal structure, without interface between based bodys, accordingly it has high bonding strength, good tenacity and elastic modulus adjacent to sclerotin, bone apatite formed by inducing in similar body fluid has good biological activity usable as biological activity surface layer of zirconium medical implant.

A zirconia sintered body having high strength and high toughness is provided, and a method for producing the same is also provided. The zirconia sintered body comprising tetragonal zirconia, wherein a full width at half maximum at (111) plane of the tetragonal zirconia obtained by X-ray diffraction pattern is from 0.38 to 4 degree. A method for producing the zirconia sintered body, wherein the method comprises steps of; molding zirconia powder having an average particle diameter of from 0.1 to 0.6 mum, a maximum particle diameter of 5 mum or less and a substantially polyhedral shape, and then sintering the molded green body under the temperature of from 1200 to 1400° C.

The invention relates to a material used for a denture, and in particular relates to a ceramic material powder used for denture preparation. The ceramic material powder comprises 90%-95% of stable tetragonal zirconia, and 2.5-3.49% of yttrium oxide used as a stabilizer, wherein a precursor is obtained by coprecipitation reaction of the ceramic material powder; the precursor is sequentially subjected to hydrothermal reaction and spray drying to obtain powder with bending strength greater than 600MPa. A method for preparing the powder comprises the following steps: a, forming 90%-95% of tetragonal zirconia, and 2.5-3.49% of yttrium oxide used as the stabilizer; b, carrying out hydrothermal reaction on the precursor produced in the step a, wherein the reaction temperature is 120-250 DEG C and the reaction time in a high-pressure reactor is 24-48 hours; c, adding a 2-5% polyvinyl alcohol solution into a product obtained in b as adhesive; d, carrying out centrifugal spray granulation on a product obtained in c at hot air temperature of 200-350 DEG C. Through the steps, high-quality ceramic powder with high bending strength greater than 600MPa, high fracture toughness, good chemical stability and good biocompatibility can be obtained.

The invention relates to an outer pipe shell material containing tetragonal zirconia and a preparation method thereof. The material comprises the components: aluminium oxide, superfine nano-zirconia and additive, wherein the aluminium oxide has the purity of 90-99.9% and the parts by weight of 70-95; the superfine nano-zirconia has the purity of 99-99.9% and the parts by weight of 5-30; the additive is one, two or more in four additives comprising yttrium oxide, magnesium oxide, calcium oxide or cerium oxide; and the four additives have the purity of 95-99.9% and the total parts by weight of 1-3. The invention adopts a thermal fluid injection molding technique to form a round or square thin wall tubular structure green body which is sintered at 1560-1580 DEG C for 20-24h. The sintered ceramic material microcosmic crystal phase contains 70-95wt% of aluminium oxide and 5-30wt% of zirconia, wherein the zirconia with the tetragonal stable phase has the weight percent of 5-70%. The invention better solves the technical problems of a thin wall mini-fuse outer pipe shell.

The present invention relates to a process for the preparation of a full-ceramic dental restoration, comprising heat pressing of a tooth coloured pressing glass on a fully or partially supporting structure of yttria doped tetragonal zirconia (YTZP), comprised of yttria doped tetragonal zirconia ceramic having a grain size, as measured by the linear intercept method, of less than 0.6 μm, wherein the pressing glass has a thermal expansion coefficient (TEC) of between 9.0 and 11.0 μm/m.K (measured in the range of from 25 to 500° C.) and wherein the pressing glass has a pressing temperature of between 750 and 1200° C. In a further aspect, the invention relates to a full-ceramic dental restoration, comprising a fully or partially supporting structure of yttria doped tetragonal zirconia (YTZP) and a heat pressed tooth coloured pressing glass, which restoration is modeled to be in occlusal contact with opposing teeth and in mesio-distal contact with neighbouring teeth.

The invention discloses a high-intensity porous bone repair material and a method for preparing the same. The method comprises the following: (1) a step of preparing a porous body, which is to use beta-tricalcium phosphate, bio-glass and a stable tetragonal zirconia power as a solid phase, add deionized water into the solid phase, add ammonium polyacrylate serving a dispersant, process the mixture by ball milling to prepare pulp, soak polyurethane foam completely into the pulp, take out the soaked foam, extrude excessive pulp out of the product so as to evenly coat the pulp on the pore walls of the porous body, dry the obtained product, place the dried product in a program control furnace or an electric resistance furnace, film the obtained product at a rising temperature and sinter the filmed product to form the porous body; (2) a step of soaking the obtained porous body in a water solution of NaOH, washing the product with deionized water in the atmosphere of ultra waves and drying the resulting product to obtain the high-intensity porous bone repair material. The high-intensity porous bone repair material of the invention has a high intensity and a high compressive strength, can be widely applied to repair skulls, frontal bones and the like and can also be used to reconstruct scaffolds of cell carriers in tissue engineering and repairing organs.

The invention discloses a ZrO2 toughened bioactive glass-ceramics of MgO-CaO-SiO2-P2O5-CaF2 system. The glass comprises the components with mass fractions as follows: 25.7-34.1% of SiO2, 3.4-4.6% of MgO, 33.7-44.8% of CaO, 12.2-16.3% of P2O5, 0.1-5% of CaF2 and 0.1-20% of ZrO2; wherein, the ZrO2 is tetragonal zirconia. The prepared ZrO2 toughened bioactive glass-ceramics of MgO-CaO-SiO2-P2O5-CaF2 system witnesses obviously improved bending strength and fracture toughness; the elastic module index of the bioactive glass-ceramics can serve as materials for restoring or replacing artificial bones and the linear expansibility index thereof meets the requirement of similarity to the linear expansibility of titanium and titanium alloy coating materials. The bioactive glass-ceramics show good bioactivity in the immersion test in the simulated body fluid.

The invention provides a tetragonal zirconia ceramic material with stable manganese oxide and a preparation method thereof. The ceramic material takes the zirconium oxide as a substrate and takes the transition metal oxide manganese oxide as a stabilizing agent. The preparation method comprises the steps as follows: the weighed mixed powder of the zirconium oxide and manganese oxide is poured into a mortar and fully ground and mixed; the powder is pressed into ceramic sheets with certain shapes by adopting a unidirectional dry press method under the pressure of 8 to 10MPa; the ceramic sheets are put into a high temperature pipe furnace to be sintered, wherein, a heat treatment regime is that the heating rate is less than 300 DEG C per hour, heat preservation is carried out for 12 to 24 hours in the argon atmosphere at 1,300 to 1,400 DEG C and the cooling is carried out on the ceramic sheets along with the furnace. The method is simple in process and low in cost. The tetragonal zirconia ceramic is prepared by a solid sintering process; the material obtained has good stability, is an excellent structural ceramic material and a solid electrolyte material and is beneficial to the application and popularization of the novel zirconia ceramic material.

The invention discloses a zirconia ceramic stabilized by rare earth oxide and manganese oxide and a method for preparing the same. The zirconia ceramic consists of a certain mol percent of zirconia, the rare earth oxide and the manganese oxide, wherein the zirconia is a matrix, and the rare earth oxide and transition metal oxide of manganese oxide serve as a stabilizing agent together. The preparation process comprises the following steps: pouring the weighed and mixed powder of the zirconia, the manganese oxide and the rare earth oxide into a mortar; after fully mixing and grinding the mixed powder, pressing the mixed powder into blank tablets at a pressure of between 8 and 10 MPa; sintering the blank tablets in a high-temperature tubular furnace; and then cooling the blank tablets with the furnace. The invention adopts the transition metal oxide and the rare earth oxide as a stabilizing agent together to prepare the stabilized zirconia, has the characteristics of simple operation method, accuracy, high efficiency, easy control of reaction conditions, full reaction and the like, and the prepared square zirconia ceramic material stabilized by the manganese oxide has good stability and conductivity.

The invention relates to a tooth zirconia/leucite composite porcelain powder and a preparation method thereof. The material includes the following components: 50 to 60 percent of Sio2, 10 to 20 percent of Al2O3, 16 to 30 percent of K2O, 2 to 5 percent of Na2O and 2 to 15 percent of ZrO2. The preparation method of the material relates to: selecting a mineral potassium feldspar powder of the first grade, adding a certain amount of potash, nanometer tetragonal zirconia powder body and ethanol to uniformly mix in a globe mill and acquiring a raw material powder after drying; placing the raw material powder into a corundum crucible to calcine under a temperature of 1000 to 3000 DEG C for 30 to 90 minutes, cooling naturally and acquiring the zirconia/leucite composite porcelain powder with a grain diameter of 10 to 30Mum after crushing the raw material through ball milling. The crystalling phases of the zirconia and the leucite in the porcelain powder are distributed uniformly. The heat expansion coefficient of the powder is (12 to 16) multiplied by 10<-6>K and the anti-bending intensity of the powder is 90 to 130MPa. The invention is also characterized by good color masking property and high fracture toughness property, etc., and lays a foundation for the clinic application of mouth porcelain repairing.

The invention relates to a tetragonal zirconia based composite ceramic ultrathin cover plate and a preparation process thereof, and belongs to the field of preparation of fine ceramics. Ceramic powder of the composite ceramic ultrathin cover plate is a trans-scale mixture formed by nanometer zirconia powder and micrometer powder, wherein the nanometer zirconia powder accounts for 40-70% of the ceramic powder in volume. The preparation process comprises the following steps: adding appropriate dispersing agent, adhesive, plasticizer and defoamer into raw materials to prepare ceramic slurry; preparing an ultrathin ceramic green tape of which the solid content is above 63% through a tape casting process; then cutting and shaping; and preparing the ultrathin composite ceramic cover plate with high flatness and controllable shrinkage ratio for a fingerprint identification function through a special sintering pot. Compared with the existing fingerprint cover plate, the composite ceramic ultrathin cover plate prepared by the invention has low sintering temperature and favorable electrical and mechanical properties, satisfies the performance requirements of fingerprint identification for high sensitivity, drop resistance, wear resistance and ultrathinness, is low in cost, and has an important practical meaning.