EP3681433A1 - Procédé de fabrication d'un corps façonné par frittage - Google Patents

Procédé de fabrication d'un corps façonné par frittage

Info

Publication number
EP3681433A1
EP3681433A1 EP18770021.6A EP18770021A EP3681433A1 EP 3681433 A1 EP3681433 A1 EP 3681433A1 EP 18770021 A EP18770021 A EP 18770021A EP 3681433 A1 EP3681433 A1 EP 3681433A1
Authority
EP
European Patent Office
Prior art keywords
blank
shaped body
sintering
raw materials
sintering behavior
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP18770021.6A
Other languages
German (de)
English (en)
Inventor
Michael Dorn
Andreas Oberländer
Christian Strasser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vita Zahnfabrik H Rauter GmbH and Co KG
Original Assignee
Vita Zahnfabrik H Rauter GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vita Zahnfabrik H Rauter GmbH and Co KG filed Critical Vita Zahnfabrik H Rauter GmbH and Co KG
Publication of EP3681433A1 publication Critical patent/EP3681433A1/fr
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/64—Burning or sintering processes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/0003—Making bridge-work, inlays, implants or the like
    • A61C13/0022—Blanks or green, unfinished dental restoration parts
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C04B35/486—Fine ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • C04B35/587—Fine ceramics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/0003—Making bridge-work, inlays, implants or the like
    • A61C13/0004—Computer-assisted sizing or machining of dental prostheses
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3225—Yttrium oxide or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/327—Iron group oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3272—Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/327—Iron group oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3275—Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/608—Green bodies or pre-forms with well-defined density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/612—Machining
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C04B2235/963—Surface properties, e.g. surface roughness
    • C04B2235/9638—Tolerance; Dimensional accuracy

Definitions

  • the present invention relates to a method for producing a shaped body from a blank, taking into account its sintering behavior, as well as a molded article produced by means of the presented method.
  • WO 2013/156483 relates to a process for producing a porous ceramic article which has at least two layers, in which the individual layers have a different presintering temperature, which is set by means of a suitable selection of the particle size. The sintering of the article is then carried out taking into account the respectively set presinter temperature.
  • WO 2015/011079 discloses a process for producing a multilayer oxide ceramic body which can be sintered without delay.
  • the sintering behavior of the individual layers is set by the doping of the ceramic with sintering aids, in particular aluminum oxide for promoting sintering and yttrium oxide for sintering inhibition.
  • US 2011/0115210 describes a method for processing a blank, wherein the blank can be densely sintered after processing under shrinkage and wherein the processing of the blank in a processing machine taking into account an individual on the blank individual magnification factor (F) to compensate for the shrinkage during dense sintering in which, for determining the magnification factor (F), a length measurement of the blank in one or more of the dimensions of length, Width and height for scale determination is performed, wherein the measured linear dimension has a known relationship to the magnification factor (F) and the type of blank is known.
  • the linear measurement of the blank can be carried out in the machining direction.
  • US 2006/0131770 describes a method for producing a dental model with the following steps: a) providing one or more fluid, solidifiable materials and one or more electrically conductive substances; b) fabricating the dental model by rapid prototyping using the fluid or solidified materials and the one or more electrically conductive substances so that the manufactured model is electrically conductive in one or more areas of its surface. Prior to making the model, geometric data of the dental model can be generated and changed to result in an oversized model that compensates for the expected dimensional changes during the manufacturing process.
  • US 2011/00639301 discloses a method of sintering an object comprising introducing an object into a high temperature furnace, heating the furnace, creating a geometric surface profile of at least a portion of the object by irradiating the object with light from a light source and detecting the object scattered therefrom Light with a detector and determining the geometric surface profile of the detected light comprises.
  • this object is achieved in that the sintering delay is determined before the processing of a blank and the processing is carried out according to the particular sintering delay.
  • an object of the present invention is a method for the production of a shaped body, comprising the following steps: a) providing a blank, wherein the blank has an inhomogeneous sintering behavior; b) working the blank from step a) to obtain a shaped body; and c) sintering the shaped body from step b) to a desired final density, characterized in that the shrinkage of the blank is determined prior to the processing of the blank and the processing is carried out in accordance with the spatially resolved magnification factors obtained in the determination.
  • the advantage of the method according to the invention is that, especially in multi-layer systems whose individual layers have different sintering behavior, the applied temperature range and thus the densities can be set very variably. Prerequisite for the temperature selection for the sintering is therefore only the mechanical workability of the blanks such as machinability and sandability for error-free production of the desired geometry.
  • a blank is to be understood, which has a different sintering behavior at different locations. This can be caused, for example, by the fact that the blank is composed of different components which each have a different sintering behavior.
  • Such an inhomogeneous sintering behavior can also occur in blanks that consist of only one component, but in which the Properties differ at different locations, for example, characterized in that the blank has a density gradient. Accordingly, a method is preferred in which the blank has at least two components with different sintering behavior or a component with an inhomogeneous sintering behavior.
  • the blank comprises a plurality of components with different sintering behavior, wherein the components are arranged differently in layers or gradually or in partial molding areas.
  • the processing of the blank takes place taking into account the shrinkage occurring during sintering.
  • the shrinkage caused by the sintering is determined in a spatially resolved manner before processing.
  • Shrinkage in the sense of the present invention is to be understood as meaning the change in length, width change and height change of the shaped body caused by the sintering.
  • the degree of shrinkage depends, inter alia, on the chemical composition, the particle size, the heating rate during the sintering process, the compact density, the density distribution in the blank and the sintering rate.
  • the inhomogeneous sintering behavior of the blank leads to an anisotropic shrinkage within the blank, which may, for example, lead to a geometric deformation of the blank.
  • the method according to the invention is characterized in that the individual shrinkage of the shaped body is determined before it is processed and the machining takes place taking into account the inhomogeneous shrinkage behavior, if appropriate using form factors.
  • the respective shrinkage of the molding is determined spatially resolved.
  • the determination is made by applying spatially resolved magnification factors in all three spatial directions for each coordinate point of the shaped body.
  • the inventive method offers the advantage that the spatially resolved magnification factors for each coordinate point and in each direction in space can be adjusted individually. So, for example the magnification factor in x-direction is different from that in y-direction. Therefore, an embodiment is preferred in which the spatially resolved magnification factors are independent of one another. Preferably, more than one magnification factor is used in the processing.
  • the blank comprises oxidic and / or non-oxidic raw materials.
  • the raw materials mentioned are preferably ceramic and metallic materials.
  • the oxidic raw materials are preferably selected from the group consisting of zirconium oxide, silicates, alumina, beryllium oxide, titanium oxide, aluminum titanate, barium titanate and mixtures thereof.
  • the non-oxidic raw materials may for example be selected from the group consisting of silicon carbide, boron nitride, boron carbide, silicon nitride, aluminum nitride, molybdenum silicide, tungsten carbide and mixtures thereof.
  • the oxidic raw materials are selected from the group consisting of zirconium oxide, silicates and aluminum oxide.
  • the blank comprises one or more materials selected from the group consisting of zirconia (ZrO 2 ), alumina (Al 2 O 3), silicon carbide (SiC), silicon nitride (S 13 N 4), silicates and mixtures thereof.
  • the oxidic raw materials can be present in a preferred embodiment together with other oxides. These further oxides are preferably stabilizing oxides.
  • the oxidic raw material is yttrium-stabilized zirconium oxide.
  • the content of further oxide 0.01 wt .-% to 20 wt .-%, preferably 0.1 to 15 wt .-% and particularly preferably 0.5 wt .-% to 10 wt. %, in each case based on the total weight of the oxidic raw material.
  • the blank comprises at least one metallic material, preferably a metallic alloy.
  • the blank additives are added, for example, to achieve certain properties. Therefore, an embodiment is preferred in which the blank has further additives.
  • additives are preferably dyes and / or coloring oxides. Particular preference is given to dyes and / or coloring oxides selected from the group consisting of oxides of yttrium, lanthanum, vanadium, terbium, titanium, manganese, magnesium, erbium, iron, copper, chromium, cobalt, nickel, selenium, silver, indium, gold and rare earth metals, and from these in particular neodymium, praseodymium, samarium and europium.
  • the amount of dyes and / or coloring oxides depends on the desired end result and may for example be in the range of a few ppm to a few percent by weight.
  • the proportion of dye and / or coloring oxide for example, 1 ppm to 500 ppm, preferably 5 ppm to 300 ppm, wherein the ppm relate to parts by mass.
  • the proportion may be 0.1% to 5.0% by weight, preferably 0.2 to 3.0% by weight, based in each case on the total weight of the blank.
  • agents can be added to the raw materials, such as binders, pressing aids and waxes.
  • these means are removed after pressing the blank, preferably by a thermal treatment of the pressed blank.
  • the blank provided in step a) of the method according to the invention is a pressed material.
  • the blank provided in step a) is a pre-sintered blank.
  • a pre-sintered blank is to be understood as meaning a blank which has already been subjected to a sintering treatment, without, however, achieving the desired final density.
  • the precise mapping of given data is of particular importance when it comes to components that are to be incorporated into a composite.
  • An example of such a compound is the human dentition in addition to the usual technical applications.
  • the method according to the invention is particularly suitable because it allows the dimensionally accurate and precise production of moldings also of ceramic materials, as usual in the field of dental restoration. Therefore, in a preferred embodiment of the method according to the invention in the resulting molded body is a dental restoration.
  • the dental restoration is preferably selected from the group consisting of dental restorations, bridge restorations, implants and implant abutments.
  • the blank is processed to obtain a shaped body.
  • the processing is preferably carried out by means of CAD / CAM method.
  • CAD / CAM method By machining by means of CAD / CAM methods, it is possible to obtain a faithful reproduction of the determined geometrical configuration of the shaped body, in which, in particular, the specific shrinkage is taken into account.
  • the shaped body can be subjected to further process steps.
  • the shaped body can be colored, wherein the coloring substances can be applied by the usual methods, such as painting or dipping in appropriate solutions.
  • step c) of the process according to the invention the shaped body obtained in step b) is sintered to a desired final density.
  • the final density of the molded article depends on the intended use. In some fields of application, it may be advantageous to give the molding as high a density as possible, which is close to the theoretically possible density.
  • a coating can be applied to the thus sintered shaped body.
  • the shaped body has a certain porosity. This is the case, for example, when the shaped body is to be subjected to further treatment steps. For example, it is possible to introduce filling materials into the pores remaining in the molding. This type of treatment is found, for example, in the manufacture of electronic components, but has also found its way into the field of dental restoration.
  • the inventive method has the advantage that the processing of the blank and the sintering of the molding to the desired final density on site, for example, the dentist, can be made. Thanks to the previously determined and provided spatially resolved magnification factors, the sintering process can be carried out in such a way that different materials can be contained in the blank and this nevertheless corresponds to the inhomogeneous sintering behavior of the desired final shape after dense sintering.
  • the inventive method further comprises providing a data set comprising the spatially resolved magnification factors obtained in determining the shrinkage of the blank.
  • the method according to the invention comprises the following steps: a) providing a blank, the blank having an inhomogeneous sintering behavior; b) determining the shrinkage of the blank to obtain a set of spatially resolved magnification factors; c) providing the set of spatially resolved magnification factors obtained in determining the shrinkage of the blank; d) working the blank to obtain a shaped article; and e) sintering the shaped body to a desired final density, the processing being carried out in accordance with the spatially resolved magnification factors obtained in determining the shrinkage.
  • the determination of the shrinkage of the blank can be carried out at any time before the processing of the blank.
  • the method according to the invention further comprises the step of checking the determined set of spatially resolved magnification factors.
  • This check preferably takes place in that the set of spatially resolved magnification factors determined in step b) of the method according to the invention is applied to a further blank to obtain a shaped body and this shaped body is then sintered to the desired final density. In this way, the quality of the determined set of spatially resolved magnification factors is ensured in order to ensure comfortable handling and a tailor-made final result.
  • the method according to the invention makes it possible to provide a blank and a set of spatially resolved magnification factors corresponding to the shrinkage of the blank. It has surprisingly been found that by providing a set of spatially resolved magnification factors which are individually adapted to the blank, a simple and convenient production of a dimensionally accurate shaped body is possible. Therefore, another object of the present invention is a kit comprising: i) a blank; and ii) a set of spatially resolved magnification factors, wherein the set of spatially resolved magnification factors is obtained by determining the shrinkage of the blank.
  • the blank is preferably a blank as described above. Particularly preferably, the blank comprises various components with different sintering behavior, wherein the components are not arranged homogeneously in the blank.
  • a further subject of the present invention is a kit comprising a blank and an information carrier, the information carrier containing a set of spatially resolved magnification factors obtained by determining the shrinkage of the blank.
  • the blank is preferably a blank as described above.
  • the blank comprises various components with different sintering behavior, wherein the components are preferably arranged differently in layers or gradually or in partial molding areas.
  • the blank and the information carrier are integrally formed.
  • the blank serves as an information carrier. In this way a simple and comfortable handling is ensured.
  • Another object of the present invention is a molded body having an inhomogeneous sintering behavior, wherein the shaped body has a shape adapted to its sintering behavior.
  • An inhomogeneous sintering behavior can occur, for example, if the molding is composed of more than one component, the components showing a different sintering behavior. In other cases, an inhomogeneous sintering behavior is present when different regions of the molding have different properties. This can be the case, for example, if the shaped body has a density gradient or was pressed inhomogeneously.
  • the shaped body according to the invention is preferably a shaped body which has at least two components with different sintering behavior or a component with inhomogeneous sintering behavior, the shape of the shaped body being adapted to the sintering behavior of the individual components.
  • sintering leads to geometric changes, which are particularly pronounced when the shaped body has an inhomogeneous sintering behavior.
  • the shaped body according to the invention is distinguished in a preferred embodiment in that it is brought by sintering in a desired shape. This can be achieved, inter alia, by the fact that the expected sintering distortion is taken into account in the shaping of the shaped body.
  • the contraction taking into account shape of the molding is specified by spatially resolved magnification factors.
  • the material of the molded article may be selected depending on the intended use.
  • the shaped body comprises oxidic and / or non-oxidic raw materials.
  • the raw materials mentioned are preferably ceramic and metallic materials.
  • the oxidic raw materials are preferably selected from the group consisting of zirconium oxide, silicates, alumina, beryllium oxide, titanium oxide, aluminum titanate, barium titanate and mixtures.
  • the non-oxidic raw materials may for example be selected from the group consisting of silicon carbide, boron nitride, boron carbide, silicon nitride, aluminum nitride, molybdenum silicide, tungsten carbide and mixtures thereof.
  • the shaped body comprises one or more materials selected from the group consisting of zirconium oxide (Zr0 2 ), aluminum oxide (Al 2 O 3 ), silicon carbide (SiC), silicon nitride (S13N4), silicates and mixtures thereof.
  • the oxidic raw materials can be present in a preferred embodiment together with other oxides. These further oxides are preferably stabilizing oxides.
  • the oxidic raw material is yttrium-stabilized zirconium oxide.
  • the content of further oxide 0.01 wt .-% to 20 wt .-%, preferably 0.1 to 15 wt .-% and particularly preferably 0.5 wt .-% to 10 wt. %, in each case based on the total weight of the oxidic raw material.
  • the shaped body comprises at least one metallic material, preferably a metallic alloy.
  • the shaped body may contain additives.
  • additives can be used, for example be given to the molded body certain properties, especially in optical terms.
  • the additives are preferably dyes and / or glass-coloring oxides. Particular preference is given to dyes and / or glass-coloring oxides selected from the group consisting of oxides of yttrium, lanthanum, vanadium, terbium, titanium, manganese, magnesium, erbium, iron, copper, chromium, cobalt, nickel, selenium, silver, indium, gold and rare earth metals, and from these in particular neodymium, praseodymium, samarium and europium.
  • additives can be used to influence, for example, the mechanical properties of the molding.
  • the molded body according to the invention is characterized in that its shape is adapted to the sintering behavior and it obtains its desired shape by sintering. Accordingly, it is particularly suitable for use as a dental restoration.
  • the shaped body according to the invention is preferably a dental restoration.
  • the dental restoration is preferably selected from the group consisting of dental restorations, bridge restorations, implants and implant abutments.
  • the molding is obtainable according to the process of the invention.
  • Another object is a molding which is obtainable by the process according to the invention.
  • the shaped body according to the invention is particularly suitable for use in the field of dental restorations. Therefore, another object of the present invention is the use of the shaped body according to the invention for the production of a dental restoration.
  • zirconia powder stabilized with yttria was pressed uniaxially on both sides to form a cuboid body.
  • a density gradient within the body is formed due to friction between the particles and the friction to the pressing die wall at the pressing pressures necessary for this material. The lowest density is found along the press neutrals. In this area occurs the lowest compression of the powder granules.
  • the pressed body was subjected to a heat treatment at temperatures up to 700 ° C to remove organic additives.
  • a second heat treatment the body was pre-sintered at temperatures in the range of 1000 ° C to 1200 ° C to 50 to 60% of its theoretical density.
  • the milled box was sintered at temperatures of 1300 ° C to 1600 ° C to the desired final density.
  • the geometry of the sintered body was scanned and recorded using a profilometer.
  • the densely sintered body has a deviation from the target geometry.
  • the reason for this is the density gradient occurring in the body, which is maintained during pre-sintering of the blank and leads to an inhomogeneous sintering behavior.
  • the sintered body therefore shows a significant deviation from the target geometry in the area of the press neutrals.
  • FIG. 1b shows the profile measurement of the milled, pre-sintered body and the densely sintered body along the plane indicated in FIG. 1a. Again, the significant deviation of the dense body from the desired cuboidal target geometry can be seen.
  • a presintered body of yttria stabilized zirconia was prepared. From the pre-sintered body, a cuboidal blank was milled, the outer dimensions of which result from the target geometry of the densely sintered body. Unlike Comparative Example 1, no uniform magnification factor was used to account for the shrinkage that occurs during sintering. Rather, the inhomogeneous sintering behavior of the body was taken into account by the dimensions of the target geometry were increased spatially resolved according to the density distribution. For this purpose, each coordinate point of the target geometry has its own magnification factor, resolved into x, y, z coordinates, assigned to obtain the geometry to be cropped.
  • the milled body was sintered analogously to Example 1 at temperatures in the range of 1300 to 1600 ° C to the desired final density, which corresponds to that of the body described in Example 1.
  • the densely sintered body was scanned with a profilometer to determine the outside dimensions.
  • FIG. 2a shows the schematic representation of the pre-sintered, milled body (light) and the densely sintered body (dark), wherein it can be clearly seen that the densely sintered body corresponds to the target geometry.
  • FIG. 2b shows the profile measurement of the milled and densely sintered body along the plane indicated in FIG. 2a.
  • the densely sintered body has no deviations from the target geometry.
  • 2nd blank consisting of four layers with different composition
  • Example 3 Different yttria-stabilized zirconia powders were layered in a die, with the powders each having different additives in the form of iron oxide, cobalt oxide and erbium oxide. The layers were uniaxially pressed on both sides to a cuboid blank. Due to the different composition of the layers results in each case a different sintering behavior.
  • the pressed body was subjected to a heat treatment at temperatures up to 700 ° C to remove organic additives.
  • a second heat treatment the body was pre-sintered at temperatures in the range of 1000 ° C to 1200 ° C to 50 to 60% of its theoretical density.
  • the milled box was sintered at temperatures of 1300 ° C to 1600 ° C to the desired final density.
  • the geometry of the sintered body was scanned and recorded using a profilometer.
  • the densely sintered body has a deviation from the target geometry. The reason for this is the different sintering behavior of the layers.
  • the densely sintered body shows a significant curvature.
  • Figure 3a shows the schematic representation of the pre-sintered, milled body (light) and dense sintered body (dark), where clearly the deviation from the target geometry can be seen.
  • Figures 3b and 3c depict the profile measurement of the pre-sintered milled body and densely sintered body along the planes indicated in Figure 3a. Again, the significant deviation of the dense body from the desired cuboidal target geometry can be seen.
  • a multilayer pre-sintered body of yttria-stabilized zirconia was prepared. From the pre-sintered Body was milled a cuboid blank, the outer dimensions of which result from the target geometry of the densely sintered body. In contrast to Comparative Example 3, no uniform magnification factor was used to account for the shrinkage that occurs during sintering. Rather, the inhomogeneous sintering behavior of the body was taken into account by the dimensions of the target geometry were increased spatially resolved. For this purpose, each coordinate point of the target geometry has its own magnification factor, resolved into x, y, z coordinates, assigned to obtain the geometry to be cropped.
  • the milled body was sintered analogously to Example 3 at temperatures in the range of 1300 to 1600 ° C to the desired final density, which corresponds to that of the body described in Example 3.
  • the densely sintered body was scanned with a profilometer to determine the outside dimensions.
  • FIG. 4a shows the schematic representation of the pre-sintered, milled body (light) and the densely sintered body (dark), wherein it can be clearly seen that the densely sintered body corresponds to the target geometry.
  • Figures 4b and 4c depict the profile measurement of the pre-sintered milled body and densely sintered body along the planes indicated in Figure 4a.
  • the densely sintered body has no deviations from the target geometry.
  • the side surfaces of the cuboid are straight and plane-parallel according to the target geometry.
  • FIG. 5 exemplarily demonstrates the use of the spatially resolved magnification factors in determining the sintering delay.
  • the method according to the invention allows individual adaptation of the magnification factors.
  • the magnification factor VGF2 at the lower level 4 in each spatial direction may be set smaller than the magnification factor VGF1 at the level 1 corner.
  • FIG. 6 likewise shows, by way of example, a multilayer shaped body whose planes have different sintering behavior.
  • optimal adaptation can be achieved by selecting the correspondingly individually adapted magnification factors. So applies in the present example VGF (x, E1, E5) ⁇ VGF (x, E3)
  • VGF (y, E1, E5) ⁇ VGF (y, E3)
  • VGF (z, E1, E5) ⁇ > VGF (z, E3).
  • the method according to the invention by using spatially resolved magnification factors, permits the dimensionally accurate production of shaped, inhomogeneous shaped bodies despite the different sintering behavior of the individual partial areas of the shaped body.

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  • Chemical & Material Sciences (AREA)
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  • Ceramic Engineering (AREA)
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  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Dentistry (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
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Abstract

La présente invention concerne un procédé permettant de fabriquer un corps façonné à partir d'une ébauche en tenant compte de son comportement au frittage ainsi qu'un corps façonné fabriqué au moyen dudit procédé.
EP18770021.6A 2017-09-15 2018-09-17 Procédé de fabrication d'un corps façonné par frittage Pending EP3681433A1 (fr)

Applications Claiming Priority (2)

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EP17191271 2017-09-15
PCT/EP2018/075056 WO2019053253A1 (fr) 2017-09-15 2018-09-17 Procédé de fabrication d'un corps façonné par frittage

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Publication number Priority date Publication date Assignee Title
DE102004052364A1 (de) 2004-10-28 2006-06-22 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH & Co. KG Verfahren zum Herstellen eines dentalen Modells, eines dentalen Modells mit darauf abgeschiedener Keramikschicht, sowie eines Dentalformteils, dentales Modell, sowie Verwendung eines 3D-Druckers und eines Kits
DE102006024489A1 (de) 2006-05-26 2007-11-29 Forschungszentrum Karlsruhe Gmbh Grünkörper, Verfahren zur Herstellung einer Keramik und deren Verwendung
DE102008013471A1 (de) 2008-03-10 2009-09-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Keramische Grünkörper mit einstellbarer Sinterschwindung, Verfahren zu ihrer Herstellug und Anwendung
DE102008020720A1 (de) 2008-04-03 2009-10-15 Sirona Dental Systems Gmbh & Co. Kg Verfahren zur Bearbeitung eines Rohlings mit einem individuellen Vergrößerungsfaktor und Rohling hierfür
DE102008024731B4 (de) 2008-05-19 2020-08-20 BAM Bundesanstalt für Materialforschung und -prüfung Verfahren und Vorrichtung zur Sinterung eines Objektes unter Bestimmung des geometrischen Oberflächenprofils des Objekts
US10391671B2 (en) 2012-04-16 2019-08-27 Vita Zahnfabrik H. Rauter Gmbh & Co. Kg Process for producing a non-dense sintered ceramic molded body having at least two layers
EP2829251B1 (fr) 2013-07-22 2019-04-10 Ivoclar Vivadent AG Contrôle de la cinétique de frittage de céramiques oxydées

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