DE19649306C2 - Ceramic investment material for the production of molds - Google Patents

Ceramic investment material for the production of molds

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DE19649306C2
DE19649306C2 DE1996149306 DE19649306A DE19649306C2 DE 19649306 C2 DE19649306 C2 DE 19649306C2 DE 1996149306 DE1996149306 DE 1996149306 DE 19649306 A DE19649306 A DE 19649306A DE 19649306 C2 DE19649306 C2 DE 19649306C2
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investment
weight
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ceramic
investment material
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DE19649306A1 (en
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Stanislav Dr Chladek
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    • 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
    • A61C13/20—Methods or devices for soldering, casting, moulding or melting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
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    • 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
    • C04B35/03—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 magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • C04B35/057—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 magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on calcium oxide
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    • 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
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    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
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    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
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Description

Die vorliegende Erfindung betrifft eine keramische Einbettmasse auf Basis von Calciumoxid zum Herstellen von Feingußformen für Titan, Zirkonium und andere Metalle und deren Legierungen, die im flüssigen Zustand hoch aggressive Schmelzen bilden.The present invention relates to a ceramic investment based on calcium oxide for the production of investment molds for titanium, zirconium and other metals and their Alloys that form highly aggressive melts in the liquid state.

In der Medizintechnik und dabei insbesondere in der Dentaltechnik haben sich Titan und seine Legierungen als Implantat- und Prothetikwerkstoff erfolgreich durchgesetzt. Es ist auch aufgrund seiner Biokompatibilität, Korrosionsbeständigkeit und guten mechanischen Eigenschaften ein nahezu idealer Werkstoff für den dentalen Zahnersatz. Diesen Vorteilen steht in der Gußtechnik jedoch die hohe Reaktivität der Titanschmelze entgegen, die ein Hindernis für weitere Verbreitung der Technologie ist.In medical technology and in particular in dental technology, titanium and successfully implemented its alloys as an implant and prosthetic material. It is also due to its biocompatibility, corrosion resistance and good mechanical Properties an almost ideal material for dental dentures. These advantages stands in casting technology, however, the high reactivity of the titanium melt, the one Obstacle to further spread of technology is.

Die üblichen Einbettmassen für die Herstellung der Gußformen sind für den Titanguß ausnahmslos ungeeignet, weil sie wenig widerstandsfähige Materialien wie Quarz bzw. Silikate, Phosphate usw. enthalten. Nach dem Eingießen des Titans in eine solche Form kommt es zur starken Reaktion der Metallschmelze mit der keramischen Formmasse und zusätzlich zur Aufhärtung und Versprödung der Titangußoberfläche durch die Sauerstoffaufnahme. Diese sog. alpha-case wird bis zu 0,5 mm dick und muß nachher entfernt werden. Damit wird die Geometrie des Gußstückes geändert bzw., bei dünnen Wandstärken, das Gußstück unbrauchbar gemacht.The usual investment materials for the production of the casting molds are for the titanium casting without exception unsuitable because they use less resistant materials such as quartz or Contain silicates, phosphates, etc. After pouring the titanium into such a mold there is a strong reaction of the molten metal with the ceramic molding compound and in addition to the hardening and embrittlement of the titanium cast surface by the Oxygen uptake. This so-called alpha case becomes up to 0.5 mm thick and has to be done afterwards be removed. This changes the geometry of the casting or, for thin ones Wall thicknesses, the casting made unusable.

Eine Einbettmasse für diese Anwendung wird in der EP 0 503 626 A1 vorgestellt. Sie enthält 40-60% Zirkonoxid, eventuell auch Aluminiumoxid oder Magnesiumoxid. Die hiermit erzielte Verbesserung ist aber nur gering, weil weiterhin mindestens 40% der Einbettmasse aus Phosphat-Binder und Quarz bestehen, die mit der Titanschmelze heftig reagieren. Ähnliche Einbettmassen mit einem Phosphat-Binder werden auch in EP 0 433 546 A1, DE 40 19 818 A1, oder DE 35 42 921 A1 beschrieben. Den Anforderungen der dentalen Titanguß­ technologie entsprechen besser keramische Einbettmassen, die auf Quarz, Silikate bzw. Phosphate großenteils verzichten, zugunsten thermodynamisch stabileren Rohstoffe. Eine solche Einbettmasse ist aus DE 38 25 250 C2 bekannt. Sie basiert auf Aluminiumoxid und Magnesiumoxid, mit Magnesiumacetat als Binder, alternativ mit kolloidalem SiO2 bzw. Ethylsilikat. Diese und der hohe Anteil an feinerem Aluminiumoxid (20 bis über 40%), das nicht ausreichend widerstandsfähig ist, führen jedoch auch hier zur schwachen Reaktion mit der Titanschmelze. Letztlich wird in EP 0 733 419 A1 eine andere Einbettmasse auf Basis von Zirkoniumoxid (bzw. Calciumzirkonat) und Magnesiumoxid mit einem Zirkonatbinder vorgeschlagen. Der Nachteil ist das hohe Gewicht und der Rohstoffpreis der ZrO2-haltigen Einbettmassen. Die Gußform aus einer solchen Einbettmasse muß vor dem Guß auf unter 500°C abgekühlt werden, weil bekanntlich das Zirkonoxid nur unter 500°C der Titan­ schmelze widersteht. Zusätzlich dazu kommt es in Gußformen nach den beiden letztlich genannten Schriften auch bei niedriger Gußtemperatur zur nachteiligen Aufnahme der Zr- bzw. Al-Ionen in die Gußoberfläche (Lenz, Dietz: Quintessenz Zahntech 21(1995) 633-645). Dies ist bei Magnesiumoxid oder Calciumoxid nicht der Fall.An investment material for this application is presented in EP 0 503 626 A1. It contains 40-60% zirconium oxide, possibly also aluminum oxide or magnesium oxide. The improvement achieved with this is only slight, because at least 40% of the investment material still consists of phosphate binder and quartz, which react violently with the titanium melt. Similar investment materials with a phosphate binder are also described in EP 0 433 546 A1, DE 40 19 818 A1, or DE 35 42 921 A1. Ceramic investment materials, which largely dispense with quartz, silicates and phosphates, meet the requirements of dental titanium casting technology in favor of thermodynamically more stable raw materials. Such an investment is known from DE 38 25 250 C2. It is based on aluminum oxide and magnesium oxide, with magnesium acetate as a binder, alternatively with colloidal SiO 2 or ethyl silicate. However, this and the high proportion of finer aluminum oxide (20 to over 40%), which is not sufficiently resistant, also lead to a weak reaction with the titanium melt. Finally, another investment material based on zirconium oxide (or calcium zirconate) and magnesium oxide with a zirconate binder is proposed in EP 0 733 419 A1. The disadvantage is the high weight and the raw material price of the ZrO 2- containing investments. The mold from such an investment must be cooled to below 500 ° C before casting, because it is known that the zirconium oxide only withstands the titanium melt below 500 ° C. In addition, casting molds according to the two last-mentioned documents also adversely absorb Zr or Al ions in the casting surface, even at low casting temperatures (Lenz, Dietz: Quintessenz Zahntech 21 (1995) 633-645). This is not the case with magnesium oxide or calcium oxide.

Dem Einsatz von Calciumoxid, einem der thermodynamisch stabilsten oxidischen Rohstoffe für diese Anwendung, steht jedoch seine heftige Reaktion mit Wasser gegenüber (Löschen von Kalk) die sehr gefährlich ist (Augen, Haut). Zudem ist es hoch feuchtigkeitsempfindlich. Das macht die Anwendung in wasserhaltigen Einbettmassen praktisch unmöglich (DE 40 19 818 A1). Aus diesem Grund wird das Calciumoxid nur in nichthärtenden Schlickergemischen des Typs CaO-Öl/Kerosin verarbeitet (EP 0 233 478).The use of calcium oxide, one of the most thermodynamically stable oxidic raw materials for this application, however, stands its violent reaction with water (extinguishing of lime) which is very dangerous (eyes, skin). It is also highly sensitive to moisture. This makes the use in water-containing investment materials practically impossible (DE 40 19 818 A1). For this reason, calcium oxide is only used in non-hardening slip mixtures Type CaO oil / kerosene processed (EP 0 233 478).

Die technische Lösung der geschilderten Probleme ist nicht nur für die dentale Titangußtechnik interessant, sondern auch für die Herstellung von Schmuck, Uhrenteilen und allgemeine in der industriellen Titanfeingußfertigung.The technical solution to the problems described is not only for the dental Titanium casting technology interesting, but also for the production of jewelry, watch parts and general in industrial precision investment casting.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine keramische Einbettmasse zu entwickeln, welche die vorstehend genannten Mängel nicht aufweist. Die aus einer solchen Einbettmasse hergestellte Gußform soll der aggressiven Metallschmelze auch bei höheren Temperaturen weitgehend widerstehen, so daß die Reaktion mit der Schmelze völlig unterbunden wird und die Aufhärtung und Aufnahme der Zr- bzw. Al-Ionen in die Oberfläche auf ein mögliches Minimum reduziert wird.The object of the present invention is to provide a ceramic investment develop that does not have the above-mentioned shortcomings. The one out of one Investment casting mold is said to be aggressive to the molten metal even at higher Temperatures largely withstand so that the reaction with the melt completely is prevented and the hardening and absorption of the Zr or Al ions in the surface is reduced to a possible minimum.

Diese Aufgabe wird erfindungsgemäß mit einer keramischen Einbettmasse gelöst, die als Hauptbestandteil 30-40% Calciumoxid in einer deaktivierten Form enthält (Elektroschmelzprodukt, bzw. totgebrannt), oder 30-65% eines Gemisches aus demselben Calciumoxid und Calciumzirkonat, mit höchstens 40% Calciumoxid. Als Bindemittel wird 0,1-4% wasserlösliches Calciumsalz einer organischer Säure zugegeben. Weiterhin enthält die Einbettmasse 15-20% Aluminiumoxid, zusammen mit 0,001-0,1% Aluminiumpulver als Härtemittel und 10-15% Magnesiumoxid für die nötige thermische Expansion. Als Anmischflüssigkeit wird Wasser, oder eine wässrige Lösung benutzt. Nach dem Anmischen entsteht eine knetbare fließfähige Masse, die selbständig zum niedrigporösen, festen keramischen Körper abbindet.This object is achieved with a ceramic investment, which as Main ingredient contains 30-40% calcium oxide in a deactivated form (Electro-melt product, or still burned), or 30-65% of a mixture of the same Calcium oxide and calcium zirconate, with a maximum of 40% calcium oxide. As a binder 0.1-4% water-soluble calcium salt of an organic acid added. Furthermore contains the investment 15-20% aluminum oxide, together with 0.001-0.1% aluminum powder Hardener and 10-15% magnesium oxide for the necessary thermal expansion. As Mixing liquid is water or an aqueous solution. After mixing  a kneadable, flowable mass is created, which automatically becomes a low-porous, solid sets ceramic body.

Dieser Problemlösung liegt die Erkenntnis zugrunde, daß sich das Calciumoxid durch spezielle Behandlung deaktivieren läßt. Zu dieser weniger üblichen Form des Calciumoxids gehören sog. Elektroschmelzprodukte, oder durch thermische Behandlung entstandenes "totgebranntes" Calciumoxid. Diese Produkte besitzen nicht die bekannte Aggressivität des gebrannten Kalkes, sind nicht hydroskopisch und lassen sich problemlos mit Wasser anmischen.This solution to the problem is based on the knowledge that the calcium oxide is found can disable special treatment. To this less common form of calcium oxide belong to so-called electro-melt products, or those created by thermal treatment "dead burned" calcium oxide. These products do not have the known aggressiveness of quicklime, are not hydroscopic and can be easily mixed with water mix.

In einer derart hergestellten Einbettmasse lassen sich einwandfreie Feingußteile aus Titan und anderen reaktiven Metallen und dessen Legierungen je nach Bedarf bei unterschiedlichen Temperaturen schaffen. Die Gußstücke haften nicht an der keramischen Gußform und können leicht entfernt werden. Die so freigelegte Metallgußoberfläche hat einen sauberen metallischen Glanz ohne, bzw. mit nur einem Bruchteil der sonst üblichen alpha-case, so daß sie nicht nachgearbeitet werden muß. Mit der erfindungsgemäßen Einbettmasse ist auch die Aufnahme der Fremdionen in die Oberfläche des Gußstückes weitgehend unterbunden, weil die Einbettmasse zu hohem Teil aus Calciumoxid und Magnesiumoxid besteht.Perfect investment castings made of titanium can be made in an investment material produced in this way and other reactive metals and their alloys as needed create different temperatures. The castings do not adhere to the ceramic Mold and can be easily removed. The exposed metal casting surface has a clean metallic shine without, or with only a fraction of the usual alpha case so that it does not have to be reworked. With the invention Investment is also the inclusion of foreign ions in the surface of the casting largely prevented because the investment material consists to a large extent of calcium oxide and Magnesium oxide exists.

Calciumoxid wird vorzugsweise als Elektroschmelzprodukt gewählt, oder in einer anderen deaktivierten Form (sog. totgebrannt), als grobes Pulver oder Sand in einer Korngröße bis höchstens 250 µm. Die optimale Menge liegt bei 30-40%. (Unter % werden ausschließlich Gewichtsprozente verstanden.) Geringere Mengen führen zu nachteilig schlechteren Gußergebnissen, größere Mengen dagegen zum nicht optimalen Verhalten der Einbettmasse. Es ist ebenfalls möglich, zusätzlich zum Calciumoxid das Calciumzirkonat anzuwenden. Die optimale Menge liegt dann bei 30-65% (mit höchstens 40% CaO).Calcium oxide is preferably chosen as an electro-melt product, or in another deactivated form (so-called dead burned), as coarse powder or sand in a grain size up to a maximum of 250 µm. The optimal amount is 30-40%. (Be below% understood only percentages by weight.) Smaller quantities lead to disadvantageous poorer casting results, larger quantities, on the other hand, for non-optimal behavior the investment. It is also possible to use calcium zirconate in addition to calcium oxide to apply. The optimal amount is then 30-65% (with a maximum of 40% CaO).

Als Bindemittel wird ein wasserlösliches Calciumsalz einer organischer Säure in einer Menge von 0,1-4% verwendet, wie z. B. Calcium-Ligninsulfonat oder Calcium-Formiat. Bei hohen Temperaturen verbrennen sie zu CaO. Es ist auch möglich, zusätzlich ein oder mehrere andere verbrennbare Binder einzusetzen, wie z. B. Cellulosederivate, Polysaccharide, oder Polyvinylalkohol.As a binder, a water-soluble calcium salt of an organic acid is used in an amount used from 0.1-4%, e.g. B. calcium lignin sulfonate or calcium formate. At high Temperatures burn them to CaO. It is also possible to add one or more use other combustible binders, such as. B. cellulose derivatives, polysaccharides, or Polyvinyl alcohol.

Zum Aushärten wird vorzugsweise 15-20% hochreaktives Aluminiumoxid in einer Korngröße bis 20 µm benutzt, in Kombination mit metallischem Aluminiumpulver (0,001-0,1%). Feines metallisches Aluminium besitzt die Eigenschaft, schon bei Raumtemperatur mit Wasser zu reagieren nach
For curing, 15-20% highly reactive aluminum oxide with a grain size of up to 20 µm is preferably used, in combination with metallic aluminum powder (0.001-0.1%). Fine metallic aluminum has the property of reacting with water even at room temperature

2Al + 3H2O → Al2O3 + 3H2 2Al + 3H 2 O → Al 2 O 3 + 3H 2

In leicht alkalischem Medium, wie dies in dem beschriebenen Einbettmassenschlicker der Fall ist, beginnt die Reaktion und damit die Festigung erst nach einigen Minuten, so daß genug Zeit für die plastische Verarbeitung des Schlickers bleibt. Die restliche Wassermenge wird vom reaktiven Aluminiumoxid aufgenommen. Damit läßt sich innerhalb einer bis weniger Stunden die Gußform ausreichend aushärten. Eine geringere Menge von Al und Al2O3 als vorzugsweise genannt führt nachteilig zu längeren Aushärtezeiten, größere Menge dagegen zur schlechteren Verarbeitung und Fließfähigkeit des Schlickers.In a slightly alkaline medium, as is the case in the investment slip described, the reaction and thus the consolidation only begins after a few minutes, so that there is enough time for the plastic processing of the slip. The remaining amount of water is absorbed by the reactive aluminum oxide. This allows the mold to harden sufficiently within one to a few hours. A smaller amount of Al and Al 2 O 3 than preferably mentioned disadvantageously leads to longer curing times, while a larger amount, on the other hand, leads to poorer processing and flowability of the slip.

Die Kontraktion der Metallschmelze beim Erstarren in der Gußform wird üblicherweise beim dentalen Metallguß mit einer entsprechenden vorherigen Volumenexpansion der Gußform ausgeglichen. Zu diesem Zweck enthält die beschriebene Einbettmasse vorzugsweise 10-15% eines feinen (1-40 µm) Magnesiumoxides. Dieser Zusatz führt beim Brand bei Temperaturen über 900°C zur Bildung von MgAl2O4 und zu einer Volumenzunahme. Eine andere Menge an reaktivem MgO außerhalb der erwähnten Grenzen führt zu nicht optimalen Expansionswerten.The contraction of the molten metal during solidification in the casting mold is usually compensated for in dental metal casting with a corresponding previous volume expansion of the casting mold. For this purpose, the described investment preferably contains 10-15% of a fine (1-40 µm) magnesium oxide. This additive leads to the formation of MgAl 2 O 4 and a volume increase in the event of fire at temperatures above 900 ° C. A different amount of reactive MgO outside the limits mentioned leads to non-optimal expansion values.

Zusätzlich zu den genannten Bestandteilen kann die Einbettmasse bis zu 25% einer groben Fraktion (Korngröße 150-600 µm) eines vorher genannten keramischen Rohstoffes enthalten. Gröbere Sande in dieser Korngröße sind reaktionsträge, nicht plastisch anmischbar, mit der Tendenz zum Entmischen und können deshalb nicht die Funktionen der vorher beschriebenen feineren Pulver ersetzen. Sie sind lediglich als Füllstoffe zuzumischen, um die Gasdurchlässigkeit der gebrannten keramischen Gußform dem Gasdruck der benutzten Gußanlage anzupassen.In addition to the components mentioned, the investment can contain up to 25% of a coarse Fraction (grain size 150-600 µm) of a previously mentioned ceramic raw material contain. Coarser sands in this grain size are inert, not plastic mixable, with a tendency to segregate and therefore cannot function replace the previously described finer powder. They are just as fillers to mix the gas permeability of the fired ceramic mold Adjust the gas pressure of the casting system used.

In einer Menge bis zu 6% können dem Pulver oder der Anmischflüssigkeit ebenfalls Zusätze zugemischt werden, die die Fließfähigkeit, Plastizität, oder andere Eigenschaften der Einbettmasse verbessern.In an amount up to 6%, the powder or the mixing liquid can also Additives are added that have fluidity, plasticity, or other properties improve the investment.

Nachfolgend soll erläutert werden, wie die praktische Herstellung der Gußform bei Verwendung der beschriebenen Einbettmasse für den Titanguß realisiert wird.The following is to explain how the practical manufacture of the mold Use of the investment described for the titanium casting is realized.

Die Einbettmasse besteht aus Pulver und wasserhaltiger Anmischflüssigkeit. Beide Komponenten werden zuerst im Verhältnis 100 g Pulver mit 12-14 ml Anmischflüssigkeit zur knetbaren Masse angerührt und schließlich im Vakuummischer zum homogenen plastischen Schlicker 30 Sec. lang angemischt. Danach wird das fertige Wachsmodell eingebettet. Die Verarbeitungszeit beträgt ca. 5 Min., später beginnt eine langsame Versteifung des Schlickers, bis in etwa 2 Stunden die Gußform eine ausreichende Härte erreicht. Dann wird sie in einen kalten, oder bereits auf bis zu 300°C vorgeheizten Brennofen eingebracht. Mit einer Geschwindigkeit bis zu 10°C/Min. wird die Endtemperatur von etwa 1000°C (±40°C) erreicht. Bei der Temperatur wird die Gußform 1 Stunde an Luft gebrannt. Danach wird der Brennofen auf die gewünschte Gußtemperatur abgekühlt. Diese sollte mindestens 20 Min. gehalten werden, um eine gleichmäßige Temperaturverteilung in der Gußform zu erreichen. Schließlich wird die Gußform aus dem Brennofen entnommen und in der Gußanlage mit Titan gegossen.The investment material consists of powder and water-based mixing liquid. Both Components are first mixed in a ratio of 100 g powder with 12-14 ml mixing liquid  Kneadable mass mixed and finally in a vacuum mixer to the homogeneous plastic Slip 30 sec. long mixed. The finished wax model is then embedded. The Processing time is approx. 5 minutes, later a slow stiffening of the Until the mold reaches sufficient hardness in about 2 hours. Then it will be they are placed in a cold or preheated furnace up to 300 ° C. With a speed of up to 10 ° C / min. the final temperature of about 1000 ° C (± 40 ° C) reached. At the temperature, the mold is fired in air for 1 hour. Then the Kiln cooled to the desired casting temperature. This should last at least 20 minutes. be held to achieve a uniform temperature distribution in the mold. Finally, the mold is removed from the kiln and in the casting system Titan cast.

Claims (6)

1. Keramische Einbettmasse zur Herstellung von Gußformen für Gußteile aus Titan, Zirkonium und anderen Metallen und deren Legierungen, die im flüssigen Zustand aggressive Schmelzen bilden, welche hauptsächlich aus einem keramischen, thermodynamisch stabilen Hauptbestandteil und einem Bindemittel besteht, dadurch gekennzeichnet, daß sie als keramischen, thermodynamisch stabilen Hauptbestandteil 30-40 Gew.-% deaktiviertes Calciumoxid (Elektroschmelzprodukt, totgebranntes Calciumoxid), oder 30-65 Gew.-% eines Gemisches aus Calciumoxid und Calciumzirkonat (CaZrO3) mit höchstens 40 Gew.-% Calciumoxid enthält und als Bindemittel 0,1-4 Gew.-% eines wasserlöslichen Calciumsalzes einer organischer Säure vorgesehen ist.1. Ceramic investment for the production of molds for castings made of titanium, zirconium and other metals and their alloys, which form aggressive melts in the liquid state, which mainly consists of a ceramic, thermodynamically stable main component and a binder, characterized in that they are ceramic , thermodynamically stable main component contains 30-40% by weight of deactivated calcium oxide (electro-melt product, still-burned calcium oxide), or 30-65% by weight of a mixture of calcium oxide and calcium zirconate (CaZrO 3 ) with a maximum of 40% by weight of calcium oxide and as a binder 0.1-4% by weight of a water-soluble calcium salt of an organic acid is provided. 2. Einbettmasse nach Anspruch 1 dadurch gekennzeichnet, daß sie zusätzlich 15-20 Gew.-% Aluminiumoxid (Al2O3) und 0,001-0,1 Gew.-% metallisches Aluminiumpulver (Al) enthält.2. Investment material according to claim 1, characterized in that it additionally contains 15-20% by weight of aluminum oxide (Al 2 O 3 ) and 0.001-0.1% by weight of metallic aluminum powder (Al). 3. Einbettmasse nach Ansprüchen 1 bis 2 dadurch gekennzeichnet, daß sie zusätzlich 10-15 Gew.-% Magnesiumoxid (MgO) enthält.3. investment material according to claims 1 to 2, characterized in that they additionally Contains 10-15 wt .-% magnesium oxide (MgO). 4. Einbettmasse nach Ansprüchen 1 bis 3 dadurch gekennzeichnet, daß sie zusätzlich bis zu 25 Gew.-% einer Fraktion der Korngröße von 150 µm bis 600 µm eines in Ansprüchen 1 bis 3 genannten keramischen Rohstoffes enthalten kann.4. investment material according to claims 1 to 3, characterized in that it additionally to to 25 wt .-% of a fraction of the grain size of 150 microns to 600 microns in Claims 1 to 3 mentioned ceramic raw material can contain. 5. Einbettmasse nach Ansprüchen 1 bis 4 dadurch gekennzeichnet, daß sie zusätzlich bis zu 6 Gew.-% verbrennbare, oder thermodynamisch stabile Zusätze enthalten kann, die die Verarbeitungseigenschaften der Einbettmasse verbessern.5. investment material according to claims 1 to 4, characterized in that it additionally to can contain 6% by weight of combustible or thermodynamically stable additives which improve the processing properties of the investment. 6. Einbettmasse nach Ansprüchen 1 bis 5 dadurch gekennzeichnet, daß sie zusätzlich ein oder mehrere wasserlösliche verbrennbare Bindemittel, insbesondere Cellulosederivate, Polysaccharide, oder Polyvinylalkohol enthalten kann.6. investment material according to claims 1 to 5, characterized in that it additionally has a or several water-soluble combustible binders, in particular cellulose derivatives, Can contain polysaccharides, or polyvinyl alcohol.
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DE102004014573A1 (en) * 2004-03-25 2005-10-27 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH & Co. KG Method for producing a muffle for fine or model casting, method for producing a metallic, ceramic or glass-ceramic cast or pressed object and kit for producing such an object

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DE10223883B4 (en) * 2002-05-29 2006-08-03 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH & Co. KG Method for producing a dental casting

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DE4019818A1 (en) * 1989-06-26 1991-01-10 Okazaki Minerals & Refining Co Precision casting of esp. false teeth - using zirconium or aluminium oxide and silicon di:oxide with ammonium prim. phosphate and magnesium oxide as binder
EP0503626A1 (en) * 1991-03-12 1992-09-16 COWADENTAL Cohen & Co. GmbH Use of an investment casting mixture, investment casting material and investment model and process for its production
DE3825250C2 (en) * 1987-07-27 1993-06-17 Kabushiki Kaisha Morita Seisakusho, Kyoto, Jp
EP0733419A1 (en) * 1995-03-21 1996-09-25 Schütz-Dental GmbH Investment casting material

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DE3825250C2 (en) * 1987-07-27 1993-06-17 Kabushiki Kaisha Morita Seisakusho, Kyoto, Jp
DE4019818A1 (en) * 1989-06-26 1991-01-10 Okazaki Minerals & Refining Co Precision casting of esp. false teeth - using zirconium or aluminium oxide and silicon di:oxide with ammonium prim. phosphate and magnesium oxide as binder
EP0503626A1 (en) * 1991-03-12 1992-09-16 COWADENTAL Cohen & Co. GmbH Use of an investment casting mixture, investment casting material and investment model and process for its production
EP0733419A1 (en) * 1995-03-21 1996-09-25 Schütz-Dental GmbH Investment casting material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004014573A1 (en) * 2004-03-25 2005-10-27 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH & Co. KG Method for producing a muffle for fine or model casting, method for producing a metallic, ceramic or glass-ceramic cast or pressed object and kit for producing such an object

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