DE19649306A1 - Ceramic embedding composition - Google Patents

Ceramic embedding composition

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Publication number
DE19649306A1
DE19649306A1 DE1996149306 DE19649306A DE19649306A1 DE 19649306 A1 DE19649306 A1 DE 19649306A1 DE 1996149306 DE1996149306 DE 1996149306 DE 19649306 A DE19649306 A DE 19649306A DE 19649306 A1 DE19649306 A1 DE 19649306A1
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investment
ceramic
calcium
material according
oxide
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DE19649306C2 (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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    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
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  • Ceramic Engineering (AREA)
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Abstract

Ceramic embedding composition contains 30-40% CaO, 30-65% CaZrO2, 30-65% CaO and CaZrO3 with <= 40% CaO.

Description

Die vorliegende Erfindung betrifft eine keramische Einbettmasse auf Basis von Calcium­ oxid und/oder Calciumzirkonat 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 and / or calcium zirconate for the production of investment molds for titanium, zirconium and other metals and their alloys that are highly aggressive in the liquid state Form melt.

In der Medizintechnik und dabei insbesondere in der Dentaltechnik hat sich Titan und seine Legierungen als Implantat- und Prothetikwerkstoff erfolgreich durchgesetzt. Es ist auch aufgrund seiner Biokompatibilität, Korrosionsbeständigkeit und guten me­ chanischen Eigenschaften ein nahezu idealer Werkstoff für den dentalen Zahnersatz. Diesen Vorteilen steht in der Gußtechnik jedoch die hohe Reaktivität der Titan­ schmelze entgegen, die ein Hindernis für weitere Verbreitung der Technologie ist.Titanium has been used in medical technology and in particular in dental technology and its alloys were successfully implemented as an implant and prosthetic material. It is also due to its biocompatibility, corrosion resistance and good me mechanical properties an almost ideal material for dental dentures. In casting technology, these advantages are matched by the high reactivity of titanium melt away, which is an obstacle to further spread of the technology.

Die üblichen Einbettmassen für die Herstellung der Gußformen sind für den Titan­ guß ausnahmslos ungeeignet, weil sie wenig widerstandsfähige Materialien wie Quarz bzw. Silikate, Phosphate usw. enthalten. Nach dem Eingießen des Titans in eine sol­ che 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 0,5 mm dick und muß nachher entfernt werden. Damit wird die Geometrie des Gußstückes geändert bzw., bei dünnen Wandstärken, der Gußstück unbrauchbar gemacht.The usual investment materials for the production of the molds are for titanium cast without exception unsuitable because they are less resistant materials such as quartz or contain silicates, phosphates, etc. After pouring the titanium into a sol form there is a strong reaction of the molten metal with the ceramic Molding compound and in addition to hardening and embrittlement of the titanium cast surface through the oxygen uptake. This so-called alpha case is up to 0.5 mm thick and must be removed afterwards. This changes the geometry of the casting or with thin walls, the casting is 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 bzw. DE 35 42 921 A1 beschrieben. Den Anforderungen der dentalen Titangußtechnologie entsprechen besser keramische Einbettmassen, die auf Quarz, Silikate bzw. Phosphate größtenteils 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 coloidalem SiO2 bzw. Ethylsilikat. Diese und der hohe Anteil an feinerem Aluminiumoxid (20 bis über 40%), das nicht ausreichend widerstandsfähig ist, führt jedoch auch hier zur schwachen Reaktion mit der Titanschmelze. Eine andere denkbare Einbettmasse könnte auf Basis Zirkoniumoxid-Magnesiumoxid mit einem Zirkonatbinder hergestellt werden, wie es aus sogenannten Kern- bzw. Feineinbettmassen bereits bekannt ist. 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 investments with a phosphate binder are also described in EP 0 433 546 A1 and DE 35 42 921 A1. Ceramic investment materials, which largely dispense with quartz, silicates or 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 coloidal 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 leads to a weak reaction with the titanium melt. Another conceivable investment material could be produced on the basis of zirconium oxide-magnesium oxide with a zirconate binder, as is already known from so-called core or fine investment materials.

Die Gußform aus einer solchen Einbettmasse muß vor dem Guß auf unter 500°C abgekühlt werden, weil bekanntlich auch das Zirkonoxid über 500°C mit der Titan­ schmelze reagiert. Zusätzlich dazu kommt es in den beiden letzlich genannten Fällen 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.The mold made from such an investment must be below 500 ° C before casting be cooled, because it is known that zirconium oxide can also be heated above 500 ° C with titanium melt reacts. In addition, it occurs in the two last-mentioned cases even at low casting temperatures for the disadvantageous absorption of the Zr or Al ions into the casting surface (Lenz, Dietz: Quintessenz Zahntech. 21 (1995) 633-645). This is not the case with magnesium oxide or calcium oxide.

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

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine keramische Einbett­ masse 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 mögliches Minimum reduziert wird.The present invention has for its object a ceramic embedding develop mass that does not have the above-mentioned shortcomings. From Such a mold made of investment is said to be aggressive metal melt Resist largely at higher temperatures, so that the reaction with the Melt is completely prevented and the hardening and absorption of the Zr or Al ions in the surface is reduced to a minimum.

Diese Aufgabe wird erfindungsgemäß mit einer keramischen Einbettmasse gelöst, die als Hauptbestandteil 30-40% Calciumoxid, oder 30-65% Calciumzirkonat, oder 30-65% ein Gemisch aus Calciumoxid und Calciumzirkonat mit höchstens 40% Calcium­ oxid enthält, sowie als Bindemittel 0,1-4% ein wasserlösliches Calciumsalz organischer Saure. 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.According to the invention, this object is achieved with a ceramic investment material, the main ingredient is 30-40% calcium oxide, or 30-65% calcium zirconate, or 30-65% a mixture of calcium oxide and calcium zirconate with a maximum of 40% calcium oxide contains, as well as 0.1-4% as a binder, a water-soluble organic calcium salt Acid. The investment also contains 15-20% aluminum oxide, together with 0.001-0.1% aluminum powder as hardening agent and 10-15% magnesium oxide for the necessary thermal expansion. Water or an aqueous one is used as the mixing liquid Solution used. After mixing, a kneadable, flowable mass is formed independently binds to the low porous, solid ceramic body.

Dieser Problemlösung liegt die Erkenntnis zugrunde, daß Calciumoxid der thermody­ namisch stabilste oxidische keramische Rohstoff für diese Anwendung ist, abgesehen von gesundheitsschädlichen (ThO2, BeO) bzw. kostenintensiven (Lanthanoiden-Oxide) Sonderchemikalien (z. B. Brauner: Dtsch. Zahnärztl. Z, 47; 8 (1992) 511-515). Zusätzlich basiert die Erfindung auf der Erkenntnis, daß Calciumoxid in einer geeigneten Form (Elektroschmelzprodukt bzw. totgebrannt), oder als Calciumzirkonat nicht die übliche Aggressivität des gebrannten Kalkes besitzt und angemischt mit einem wasserlöslichen Calciumsalz organischer Säure und Wasser sich problemlos zum plastischen Schlicker verarbeiten läßt. Die bekannte heftige Reaktion bleibt dabei aus. Bisher wurde Calciumoxid nur mit nicht-wasserhaltigen, organischen Flüssigkeiten wie Öl, Kerosin usw. zu nicht selbsthärtenden Massen verarbeitet.This problem-solving is based on the knowledge that calcium oxide is the thermodynamically most stable oxidic ceramic raw material for this application, apart from harmful (ThO 2 , BeO) or cost-intensive (lanthanoid oxides) special chemicals (e.g. Brauner: Dtsch. Zahnärztl. Z, 47: 8 (1992) 511-515). In addition, the invention is based on the knowledge that calcium oxide in a suitable form (electro-melt product or still burned) or as calcium zirconate does not have the usual aggressiveness of the burnt lime and, mixed with a water-soluble calcium salt of organic acid and water, can easily be processed into a plastic slip. The well-known violent reaction does not occur. So far, calcium oxide has only been processed with non-water-containing, organic liquids such as oil, kerosene etc. to form non-self-curing compounds.

In einer derart hergestellten Einbettmasse lassen sich einwandfreie Feingußteile aus Titan und anderen aktiven Metallen und dessen Legierungen je nach Bedarf bei unterschiedlichen Temperaturen schaffen. Die Gußstücke haften nicht an der kera­ mischen Gußform und können leicht entfernt werden. Die so freigelegte Metallguß­ oberfläche 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 Calcium- und Magnesiumoxid besteht.Perfect investment castings can be made in an investment material produced in this way Titanium and other active metals and their alloys as needed  create different temperatures. The castings do not adhere to the kera mix mold and can be easily removed. The metal casting thus exposed surface has a clean metallic shine without or with only a fraction the usual alpha case, so that it does not have to be reworked. With the Investment material according to the invention is also the inclusion of foreign ions in the Surface of the casting largely prevented because the investment is too high Part consists of calcium and magnesium oxide.

Calciumoxid wird vorzugsweise als Elektroschmelzprodukt gewählt, oder in einer anderen desaktivierten Form (sog. totgebrannt), als grobes Pulver oder Sand in einer Korngröße 0 bis höchstens 250 µm. Die optimale Menge liegt bei 30-40%. (Unter % werden in der ganzen Schrift ausschließlich Gewichtsprozente verstanden.) Alternativ zum Calcium­ oxid kann auch die Verbindung Calciumzirkonat CaZrO3 in der gleichen Korngröße eingesetzt werden. Optimale Menge liegt bei 30-65%. Geringere Mengen führen in beiden Fallen zu nachteilig schlechteren Gußergebnissen, größere Mengen dagegen zum nicht optimalen Verhalten der Einbettmasse. Es ist ebenfalls möglich, CaO und CaZrO3 gleichzeitig anzuwenden, wobei die optimale Menge der beiden Komponenten zusammen zwischen 30 bis 65% liegt und CaO mit höchstens 40% vertreten ist.Calcium oxide is preferably chosen as an electrical melt product, or in another deactivated form (so-called dead-burned), as coarse powder or sand with a grain size of 0 to at most 250 µm. The optimal amount is 30-40%. (% Is understood throughout the entire text to mean only percentages by weight.) As an alternative to calcium oxide, the compound calcium zirconate CaZrO 3 can also be used in the same grain size. Optimal amount is 30-65%. In both cases, smaller quantities lead to disadvantageously poorer casting results, while larger quantities lead to less than optimal behavior of the investment. It is also possible to use CaO and CaZrO 3 at the same time, the optimal amount of the two components together being between 30 to 65% and CaO being represented with a maximum of 40%.

Als Bindemittel wird erfindungsgemäß 0,1-4% ein wasserlösliches Calciumsalz organischer Säure 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.According to the invention, 0.1-4% of a water-soluble calcium salt is used as the binder organic acid used such. B. calcium lignin sulfonate or calcium formate. At high temperatures they burn to CaO. It is also possible to add one or use several other combustible binders, such as. B. cellulose derivatives, Polysaccharides, or polyvinyl alcohol.

Zum Aushärten wird vorzugsweise 15-20% hochreaktives Aluminiumoxid in der Korngröße 0-20 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 0-20 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

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

In leicht alklichem Medium, wie dies in dem beschriebenen Einbettmassenschlicker der Fall ist, beginnt die Reaktion und damit die Verfestigung erst nach einigen Minuten, so daß genug Zeit für die plastische Verarbeitung des Schlickers bleibt. Die restliche Wassermenge wird vom reaktiven Aluminiumoxid aufgenommen, das dabei zum starren Körper abbindet. Damit läßt sich innerhalb ein bis weniger Stunden die Gußform ausreichend aushärten. Eine geringere Menge von Al und Al2O2 als vorzugs­ weise genannt führt nachteilig zu längeren Aushärtezeiten, größere Menge dagegen, wegen der großen Oberfläche der beiden Substanzen, 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 solidification only takes 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, which binds to the rigid body. This allows the mold to harden sufficiently within one to a few hours. A smaller amount of Al and Al 2 O 2 as preferred, leads disadvantageously to longer curing times, but a larger amount, because of the large surface area of the two substances, leads to poorer processing and flowability of the slip.

Die Kontraktion der Metallschmelze beim Erstaren in der Gußform wird üblicher­ weise beim dentalen Metallguß mit einer entsprechenden vorherigen Volumenexpan­ sion der Gußform ausgeglichen. Zu diesem Zweck enthält die beschriebene Einbett­ masse vorzugsweise 10-15% eines feinen (0-40 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 erwähn­ ten Grenzen resultiert in nicht optimalen Expansionswerten.The contraction of the molten metal upon 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 (0-40 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 results in non-optimal expansion values.

Zusätzlich zu den genannten Betendteilen 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 der Einbettmasse zuzumischen, um die Gasdurchlässigkeit der gebrannten keramischen Gußform dem Gasdruck der benutzten Gußanlage anzupassen.In addition to the above-mentioned parts of the bed, the investment can contain up to 25% coarse fraction (grain size 150-600 µm) of a previously mentioned ceramic Contain raw material. Coarser sands in this grain size are inert, not plastically mixable with the tendency to segregate and therefore cannot Replace functions of the finer powders previously described. They are just as Add fillers to the investment material to increase the gas permeability of the fired ceramic mold to adjust the gas pressure of the casting system used.

In einer Menge bis zu 6% können dem Einbettmassenpulver oder der Anmisch­ flüssigkeit ebenfalls Zusätze zugemischt werden, die die Fließfähigkeit, Plastizität oder andere Eigenschaften des Schlickers verbessern.Up to 6% of the investment powder or the mixture can be used Liquid additives are also added, which increase the fluidity, plasticity or improve other properties of the slip.

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 Flüssigkeit zur knetbaren Masse angerührt und schließlich im Vakuummischer zum homogenen plastischen fließfähigen Schlicker 30 Sekunden angemischt. Danach wird das fertige Wachsmodell eingebettet. Die Verarbeitungszeit beträgt ca. 5 Minuten, später be­ ginnt 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 bis 10°C/Minute wird die Endtemperatur von ca. 1000°C (±40°C) erreicht, bei der die Gußform 1 Stunde in oxidierender Atmosphäre (an Luft) gebrannt wird. Nachher wird der Brennofen auf die gewünschte Gußtemperatur abgekühlt. Die sollte mindestens 20 Minuten 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 liquid Kneadable mass mixed and finally in a vacuum mixer to homogeneous plastic flowable slip mixed for 30 seconds. After that the finished Wax model embedded. The processing time is about 5 minutes, later be a slow stiffening of the slip begins, until the mold is in about 2 hours achieved sufficient hardness. Then it turns into a cold or already on up to 300 ° C preheated furnace. With up to 10 ° C / minute Final temperature of approx. 1000 ° C (± 40 ° C) reached, at which the mold in 1 hour oxidizing atmosphere (in air) is burned. Afterwards the kiln will open cooled the desired casting temperature. That should last at least 20 minutes in order to achieve an even temperature distribution in the mold. Finally, the mold is removed from the kiln and in the casting plant cast with titanium.

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, in der Medizintechnik und dabei insbesondere in der Dentaltechnik, in der Schmuck- und Uhrenindustrie, oder in der industriellen Fein­ gußfertigung, welche hauptsächlich aus einem keramischen, thermodynamisch stabilen Hauptbestandteil und einem Bindemittel besteht, dadurch gekennzeichnet, daß sie als keramischen, thermodynamisch stabilen Hauptbestandteil 30-40% Calciumoxid (CaO), oder 30-65% Calciumzirkonat (CaZrO2),
oder 30-65% ein Gemisch aus Calciumoxid (CaO) und Calciumzirkonat (CaZrO3) mit höchstens 40% Calciumoxid (CaO) enthält
und als Bindemittel 0,1-4% ein wasserlösliches Calciumsalz organischer Säure vorge­ sehen 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, in medical technology and in particular in dental technology, in the jewelry and watch industry, or in industrial Fine cast production, which mainly consists of a ceramic, thermodynamically stable main component and a binder, characterized in that it as a ceramic, thermodynamically stable main component 30-40% calcium oxide (CaO), or 30-65% calcium zirconate (CaZrO 2 ),
or 30-65% contains a mixture of calcium oxide (CaO) and calcium zirconate (CaZrO 3 ) with a maximum of 40% calcium oxide (CaO)
and a water-soluble calcium salt of organic acid is provided as the binder 0.1-4%. 2. Einbettmasse nach Anspruch 1, dadurch gekennzeichnet, daß sie zusätzlich 15-20% Aluminiumoxid (Al2O2) und 0,001-0,1% metallisches Aluminiumpulver (Al) enthält.2. Investment material according to claim 1, characterized in that it additionally contains 15-20% aluminum oxide (Al 2 O 2 ) and 0.001-0.1% metallic aluminum powder (Al). 3. Einbettmasse nach Ansprüchen 1 bis 2, dadurch gekennzeichnet, daß sie zusätzlich 10-15% Magnesiumoxid (MgO) enthält.3. investment material according to claims 1 to 2, characterized in that it additionally Contains 10-15% magnesium oxide (MgO). 4. Einbettmasse nach Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß sie zusätzlich bis zu 25% einer Fraktion der Korngröße mindestens 150 µm und höchstens 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 up to 25% of a fraction of grain size at least 150 µm and at most 600 µm of a ceramic raw material mentioned in claims 1 to 3. 5. Einbettmasse nach Ansprüchen 1 bis 4, dadurch gekennzeichnet, daß sie zusätzlich bis zu 6% 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 may contain up to 6% combustible or thermodynamically stable additives that improve the processing properties of the investment. 6. Einbettmasse nach Ansprüchen 1 bis 5, dadurch gekennzeichnet, daß sie zusätzlich einen oder mehrere wasserlösliche verbrennbare Bindemittel wie z. B. Cellulosederivate, Polysaccharide oder Polyvinylalkohol enthalten kann.6. investment material according to claims 1 to 5, characterized in that it additionally one or more water-soluble combustible binders such as e.g. B. cellulose derivatives, May contain polysaccharides or polyvinyl alcohol.
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EP1366727A1 (en) * 2002-05-29 2003-12-03 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH &amp; Co. Preparation and use of quartz free investment material

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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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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 &amp; 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 &amp; 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
EP1366727A1 (en) * 2002-05-29 2003-12-03 BEGO Bremer Goldschlägerei Wilh. Herbst GmbH &amp; Co. Preparation and use of quartz free investment material

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