JPH0320292B2 - - Google Patents
Info
- Publication number
- JPH0320292B2 JPH0320292B2 JP17647886A JP17647886A JPH0320292B2 JP H0320292 B2 JPH0320292 B2 JP H0320292B2 JP 17647886 A JP17647886 A JP 17647886A JP 17647886 A JP17647886 A JP 17647886A JP H0320292 B2 JPH0320292 B2 JP H0320292B2
- Authority
- JP
- Japan
- Prior art keywords
- magnesia
- investment material
- casting
- mold
- alumina
- 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.)
- Expired
Links
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 60
- 239000000463 material Substances 0.000 claims description 43
- 239000000395 magnesium oxide Substances 0.000 claims description 29
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 13
- -1 alkali metal carboxylates Chemical class 0.000 claims description 13
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 13
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 10
- UEGPKNKPLBYCNK-UHFFFAOYSA-L magnesium acetate Chemical compound [Mg+2].CC([O-])=O.CC([O-])=O UEGPKNKPLBYCNK-UHFFFAOYSA-L 0.000 claims description 9
- 239000011654 magnesium acetate Substances 0.000 claims description 9
- 235000011285 magnesium acetate Nutrition 0.000 claims description 9
- 229940069446 magnesium acetate Drugs 0.000 claims description 9
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 8
- 229910052906 cristobalite Inorganic materials 0.000 claims description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 6
- 229910052783 alkali metal Inorganic materials 0.000 claims description 6
- 239000008119 colloidal silica Substances 0.000 claims description 4
- VSGNNIFQASZAOI-UHFFFAOYSA-L calcium acetate Chemical compound [Ca+2].CC([O-])=O.CC([O-])=O VSGNNIFQASZAOI-UHFFFAOYSA-L 0.000 claims description 3
- 239000001639 calcium acetate Substances 0.000 claims description 3
- 235000011092 calcium acetate Nutrition 0.000 claims description 3
- 229960005147 calcium acetate Drugs 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims 1
- 150000003839 salts Chemical class 0.000 claims 1
- 238000005266 casting Methods 0.000 description 22
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 11
- 239000010936 titanium Substances 0.000 description 11
- 229910052719 titanium Inorganic materials 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 229910019142 PO4 Inorganic materials 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 235000021317 phosphate Nutrition 0.000 description 6
- 238000007711 solidification Methods 0.000 description 6
- 230000008023 solidification Effects 0.000 description 6
- 239000007789 gas Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000004568 cement Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 4
- 239000010452 phosphate Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 229920001817 Agar Polymers 0.000 description 3
- 239000008272 agar Substances 0.000 description 3
- 150000001340 alkali metals Chemical class 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 150000007942 carboxylates Chemical class 0.000 description 3
- 239000002241 glass-ceramic Substances 0.000 description 3
- 239000010440 gypsum Substances 0.000 description 3
- 229910052602 gypsum Inorganic materials 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 229910001069 Ti alloy Inorganic materials 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000000788 chromium alloy Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 2
- 239000002341 toxic gas Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 150000001734 carboxylic acid salts Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910000623 nickel–chromium alloy Inorganic materials 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Mold Materials And Core Materials (AREA)
Description
（産業上の利用分野）
この発明はチタン、チタン合金、コバルト・ク
ロム合金、ニツケル・クロム合金等の比較的溶融
温度が高く、かつ溶融状態において高い活性のあ
る金属、又は、鋳造可能なセラミツクスもしく
は、ガラスセラミツクスを鋳造するための高温安
定型埋没材に関するものである。
（従来の技術及びその問題点）
従来、高温安定型埋没材としてクリストバライ
ト（SiO2）を主成分として石膏やリン酸塩を結
合材として加えたものが用いられている。しかし
これらの埋没材は金属溶湯の温度が高いと結合材
である石膏やリン酸塩が分解して亜硫酸ガスや五
酸化リンのガスを発生し鋳造体の肌荒れ、硬化、
脆化、変色、鋳造巣等の欠陥を生じ易い欠点を有
している。さらに前記金属のうちでも特に高温活
性が高いチタン、チタン合金を鋳造する場合は、
前記の分解発生ガスによる著しい悪影響を受ける
のみならず骨材であるクリストバライト（SiO2）
とも反応し前記鋳造欠陥は一段と甚だしくなる。
また近年、開発が進んでいる鋳造可能なガラスセ
ラミツクス、セラミツクスに於いても、従来の埋
没材を用いての鋳造では鋳肌の荒れや特性の劣化
を生じる。また、所定の特性を得る為に鋳造後、
鋳型に鋳込まれた状態で20℃〜800℃にて熱処理
を必要とする場合もあり、その間に鋳造物に埋没
材が焼き付き、肌荒れを生じる。これらの欠点を
解消させるべくマグネシアセメントを主成分とし
た埋没材が開発されつつあるが、マグネシアはチ
タンのような活性金属とか、ガラスセラミツクス
とは反応しにくいものの、つぎのような著しい欠
点を有している。
(イ) マグネシア系埋没材は水で混練後、乾燥、焼
成されるが乾燥時、焼成時ともに著しく収縮す
るので鋳型にクラツクを生じ鋳造体にバリを生
じやすくなる。また、マグネシアは流動性が悪
く細部に流れ込み難いという著しい欠点も有し
ている。更に、金属床を鋳造するのに寒天印象
材を用いると、従来のマグネシア系埋没材に
は、著しい肌荒れとクラツクを生じる。
(ロ) 溶融金属の凝固収縮を補償することができず
例えば歯科等の用途においては支台歯への不適
合や、義歯床の不適合という欠陥をひきおこ
す。
(ハ) マグネシアセメントは、凝固時間が24時間と
極端に長く、非実用的である。
(ニ) 凝固時間を短縮する為に、アルカリ金属また
はアルカリ土類金属の炭酸水素塩とかリン酸塩
とかを添加する方法（例えば特開昭59−218237
号公報…以下では先行技術とする）も発表され
てはいるが、添加率に対する凝固時間の変化率
が急激過ぎるので埋没材製造時に極めて高い混
合精度を必要とし、もしこの精度が悪いと全く
使用に耐えないものとなる欠点を有している。
また、炭酸水素塩では前記マグネシアの欠点で
ある流動性の悪さを改善することはできず、さ
らに、リン酸塩は鋳型の焼成中には分解せず、
鋳造時の高温で分解して有毒ガスを発生し溶湯
との反応により鋳造欠陥を引き起こすという著
しい欠点を有している。
そこで、本発明者は、種々の実験を繰り返すこ
とにより、マグネシア、ジルコニア、アルミナ、
マグネシア・アルミナの１種又は２種以上の材料
を骨材とし、これにアルカリ金属又はアルカリ土
類金属のカルボン酸塩のうち少なくとも１つもし
くは両者を２〜14％（重量）添加してなる高温安
定型埋没材は、前記マグネシウム系埋没材の欠点
であるクラツクの発生頻発、長い凝固時間、寒天
印象材による肌荒れ、流動性の悪さ等を驚異的に
解消できること、また、カルボン酸塩は高温にお
いてもリン酸塩の様な有毒ガスは発生せず鋳型の
焼成中に炭酸ガス、一酸化炭素、水蒸気となつて
発散してしまい鋳造物に悪影響を与えないという
こと、鋳造物に若干の肌荒れは生じるが、前記組
成の埋没材に更にクリストバライト又はコロイダ
ルシリカを２〜30％（重量）添加して略200℃以
上の温度で鋳造すれば、前記膨張模型を用いなく
ても適合可能なことを知見し、本発明を開発する
に至つたものである。
（問題点を解決するための手段）
本発明は、マグネシア（MgO）、ジルコニア
（ZrO2）、アルミナ（Al2O3）及びマグネシア・ア
ルミナ（MgO・Al2O3）のうちの１種又は２種以
上の材料を骨材とし、これにアルカリ金属のカル
ボン酸塩及びアルカリ土類金属のカルボン酸塩よ
り選ばれた少なくとも１つもしくは両者を２〜14
％（重量）添加してなる高温安定型埋没材に関す
る。望ましい実施例に於て、上記カルボン酸塩及
びアルカリ土類金属のカルボン酸塩、とりわけ酢
酸マグネシウムが採用され、更に埋没材中には、
クリストバライト又はコロイダルシリカのうち１
種又は２種を２〜30％（重量）添加したものが採
択される。
（作用）
本発明に係わる高温安定型埋没材を構成する
MgO，ZrO2，Al2O3及びMgO・Al2O3のうちの
１種又は２種以上からなる骨材は、酢酸マグネシ
ウムや酢酸カルシウムなどのアルカリ土類金属の
カルボン酸塩及びアルカリ金属のカルボン酸塩の
うち少なくとも１つもしくは２種の２〜14％（重
量）の添加により鋳造時の乾燥凝固や焼結による
収縮を抑制される。
上記に於いて添加量が２％に満たない場合は、
クラツクが発生し易くなつたり、練和した埋没材
の流動性が悪化する。逆に14％を超えると練和や
流し込みに必要な可使時間が短かくなり直ぐ固ま
り易くなる。更に、上記埋没材において、クリス
トバライト又はコロイダルシリカのうちの１種又
は２種を２〜30％（重量）添加した場合には、埋
没材の結晶変態時に膨張作用を行なわせ埋没材の
焼成に伴う収縮と金属の収縮との差を補償する。
上記に於いて添加量が２％未満の場合は鋳型の
膨張に寄与せず、逆に30％を超えると耐熱性が劣
り、クラツクが這り易くなる。
（実施例）
以下に実施例により更に詳細に説明する。
（実施例 １）
まず、本発明に係る埋没材として（表１）の代
表組成で構成した。
(Industrial Application Field) This invention applies to metals such as titanium, titanium alloys, cobalt-chromium alloys, and nickel-chromium alloys that have a relatively high melting temperature and are highly active in the molten state, or to castable ceramics or , relates to a high temperature stable investment material for casting glass ceramics. (Prior Art and its Problems) Conventionally, as a high-temperature stable investment material, a material containing cristobalite (SiO 2 ) as a main component and gypsum or phosphate as a binder has been used. However, when the temperature of the molten metal in these investment materials is high, the binding materials such as gypsum and phosphate decompose, producing sulfur dioxide gas and phosphorus pentoxide gas, which can cause the surface of the cast object to become rough, harden, and
It has the disadvantage of being susceptible to defects such as embrittlement, discoloration, and casting cavities. Furthermore, when casting titanium or titanium alloy, which has particularly high high temperature activity among the above metals,
Cristobalite (SiO 2 ), which is aggregate, is not only affected by the above-mentioned decomposition gases, but also
This also causes the casting defects to become even more serious.
Further, even in the case of castable glass ceramics and ceramics, which have been developed in recent years, casting using conventional investment materials causes roughness of the casting surface and deterioration of properties. In addition, in order to obtain the specified characteristics, after casting,
In some cases, heat treatment is required at 20°C to 800°C while the product is cast in a mold, during which time the investment material seizes on the casting and causes surface roughness. In order to overcome these drawbacks, investment materials based on magnesia cement are being developed, but although magnesia does not easily react with active metals such as titanium or glass ceramics, it has the following significant drawbacks: are doing. (a) Magnesia-based investment materials are kneaded with water, dried, and fired, but because they shrink significantly during both drying and firing, they tend to crack the mold and cause burrs on the cast body. Furthermore, magnesia has a significant drawback in that it has poor fluidity and is difficult to flow into fine details. Furthermore, when agar impression material is used to cast a metal floor, the conventional magnesia-based investment material causes significant roughness and cracks. (b) It is not possible to compensate for solidification shrinkage of molten metal, which causes defects such as non-fitting of abutment teeth and non-fitting of denture bases in applications such as dentistry. (c) Magnesia cement has an extremely long solidification time of 24 hours, making it impractical. (d) A method of adding hydrogen carbonates or phosphates of alkali metals or alkaline earth metals to shorten the coagulation time (for example, JP-A-59-218237
Publication No. 1 (hereinafter referred to as prior art) has been published, but since the rate of change in solidification time with respect to addition rate is too rapid, extremely high mixing precision is required when manufacturing investment materials, and if this precision is poor, it may not be used at all. It has drawbacks that make it unbearable.
In addition, hydrogen carbonate cannot improve the poor fluidity that is the disadvantage of magnesia, and furthermore, phosphate does not decompose during mold firing,
It has the significant disadvantage that it decomposes at the high temperatures during casting, producing toxic gas, and causing casting defects due to reaction with the molten metal. Therefore, by repeating various experiments, the present inventor discovered magnesia, zirconia, alumina,
A high-temperature product made by using one or more materials such as magnesia and alumina as aggregate, and adding at least one or both of alkali metal or alkaline earth metal carboxylates in an amount of 2 to 14% (by weight). Stable investment materials can surprisingly overcome the disadvantages of magnesium-based investment materials, such as frequent occurrence of cracks, long solidification times, rough skin caused by agar impression materials, and poor fluidity. However, toxic gases like phosphates are not generated, and are emitted as carbon dioxide, carbon monoxide, and water vapor during the firing of the mold, and do not have any negative effect on the castings. However, it has been found that if 2 to 30% (by weight) of cristobalite or colloidal silica is added to the investment material with the above composition and cast at a temperature of approximately 200°C or higher, it can be made compatible without using the expansion model. This led to the development of the present invention. (Means for Solving the Problems) The present invention provides one or more of magnesia (MgO), zirconia (ZrO 2 ), alumina (Al 2 O 3 ), and magnesia/alumina (MgO.Al 2 O 3 ), or Two or more materials are used as aggregate, and at least one or both selected from alkali metal carboxylates and alkaline earth metal carboxylates are added to the aggregates.
% (by weight) of a high temperature stable investment material. In a preferred embodiment, the carboxylates and alkaline earth metal carboxylates, particularly magnesium acetate, are employed, and the investment material further contains:
1 of cristobalite or colloidal silica
A product containing 2 to 30% (by weight) of one or two species is adopted. (Function) Constituting the high temperature stable investment material according to the present invention
Aggregates consisting of one or more of MgO, ZrO 2 , Al 2 O 3 and MgO・Al 2 O 3 are composed of alkaline earth metal carboxylates such as magnesium acetate and calcium acetate, and alkali metal carboxylates such as magnesium acetate and calcium acetate. By adding 2 to 14% (by weight) of at least one or two of the carboxylic acid salts, shrinkage due to dry solidification and sintering during casting can be suppressed. If the amount added is less than 2% in the above,
Cracks are more likely to occur, and the fluidity of the mixed investment material deteriorates. On the other hand, if it exceeds 14%, the pot life required for kneading and pouring will be shortened and it will tend to harden quickly. Furthermore, if 2 to 30% (by weight) of one or two of cristobalite or colloidal silica is added to the above-mentioned investment material, an expansion effect will be performed during the crystal transformation of the investment material, resulting in an increase in the temperature associated with the firing of the investment material. Compensate for the difference between shrinkage and metal shrinkage. In the above, if the amount added is less than 2%, it will not contribute to the expansion of the mold, and if it exceeds 30%, heat resistance will be poor and cracks will easily form. (Example) A more detailed explanation will be given below using an example. (Example 1) First, an investment material according to the present invention was constructed with the typical composition shown in Table 1.
【表】
即ち、本実施例ではカルボン酸塩として酢酸マ
グネシウムを用いた。酢酸マグネシウムの添加量
に対する埋没材硬化時間の変化、寒天印象に埋没
した時のクラツク発生の有無等を第１図に示す。
第１図から判るように、酢酸マグネシウム添加の
効果は著しいものである。更に酢酸マグネシウム
は焼成後に酢酸分は揮散しマグネシアとなるので
チタンなどの高温活性の高い金属に悪影響を与え
ない。更に添加量が少々変動しても、その効果に
著変はなく、安定している。但しあまり多く加え
過ぎると可使時間が短か過ぎたりクラツクが発生
しやすくなる。
尚、本実施例に用いた真空溶解鋳造装置として
は、第２図のものを用いた。その内部に通湯口８
を有するガイドブツシユ７を貫通させた１７を介
して少なくともリーク量を10−４・torr／sec
以下となした密壁１５で形成された溶解室３８と
鋳込室３９とを上下に対置してなる気密状の装置
本体を設置し、しかも上記溶解室３８内には反射
板４を該溶解室３８内壁に沿つて配設し、この反
射板４で包囲された溶解室３８内には、鋳造する
例えば純チタン又はチタンを主成分とする合金３
のインゴツトもしくは不定形スクラツプを収容す
る傾動可能なルツボ５と、該ルツボ５の開口部６
と略対向してアーク発生装置Ａ、例えば図示した
ように溶解室３８上部から気密絶縁ブツシユ３５
を解して溶解室３８内に挿入されたアーク発生電
極２と、この電極２にアーク発生用直流電源３３
により電極リード１３，１４を通じてアーク柱１
を発生させるようにしたアーク発生装置Ａを使用
した。図中９は鋳型、１０は同テーブル、２８は
キヤビイテイ、２５は不活性ガスボンベを夫々示
す。
（実施例 ２）
本実施例では、マグネシアセメントが収縮し金
属の凝固収縮を補償しえないという欠点を解消す
る為に、更にクリストバライトを加えたものであ
る。代表組成を（表２）に示す。クリストバライ
トは、略200℃以上で大きな膨張をし歯科用埋没
材の成分として知られているが、リン酸塩とか石
膏をバインダーとして用いているので、チタンな
どの鋳造には適さない。しかし本発明のマグネシ
ア埋没材は前記バインダーを用いてはいないの
で、前記のような分解ガスは、発生しない。従つ
てクリストバライトを含有していても、従来の歯
科用埋没材を用いた時のように、著しい鋳造物の
肌荒れ及び表面硬化による使用不能といつたこと
は起こらない。本組成の埋没材を用いて第３図に
示した金型Ｍで形成したワツクスパターンを埋没
し鋳型温度400℃で鋳造してキヤツプＣを得た場
合と、マグネシアセメントで埋没してキヤツプＣ
を得た場合の夫々のキヤツプＣを金型Ｍに対して
嵌帽テストした際辺縁部の浮き上がり量の比較を
（表３）に示す。この（表３）より本発明組成に
より例えば上記金型（支台歯と見做す）への適合
が大幅に改善されたことがわかる。尚、本実験に
ついても前記アーク鋳造機を用いた。[Table] That is, in this example, magnesium acetate was used as the carboxylate. Figure 1 shows the changes in the hardening time of the investment material with respect to the amount of magnesium acetate added, the occurrence of cracks when the investment material was embedded in an agar impression, etc.
As can be seen from FIG. 1, the effect of adding magnesium acetate is remarkable. Furthermore, after firing, the acetic acid content of magnesium acetate evaporates and becomes magnesia, so it does not have an adverse effect on metals that are highly active at high temperatures, such as titanium. Furthermore, even if the amount added changes slightly, the effect remains stable without any significant change. However, if too much is added, the pot life will be too short and cracks will easily occur. The vacuum melting and casting apparatus used in this example was the one shown in FIG. There are 8 hot water holes inside it.
The amount of leakage is at least 10-4・torr/sec through the guide bush 7 having a
An airtight device main body is installed in which a melting chamber 38 and a casting chamber 39 formed by the following sealed walls 15 are placed vertically opposite each other. Inside the melting chamber 38, which is disposed along the inner wall of the chamber 38 and surrounded by the reflector 4, there is placed, for example, pure titanium or a titanium-based alloy 3 to be cast.
a tiltable crucible 5 for accommodating ingots or irregularly shaped scrap; and an opening 6 of the crucible 5.
Approximately opposite to the arc generating device A, for example, as shown in the figure, the airtight insulating bush 35 is
The arc generating electrode 2 is inserted into the melting chamber 38 through the
arc column 1 through electrode leads 13 and 14.
Arc generator A was used to generate arc. In the figure, 9 is a mold, 10 is the same table, 28 is a cavity, and 25 is an inert gas cylinder. (Example 2) In this example, cristobalite was further added in order to overcome the drawback that magnesia cement shrinks and cannot compensate for the solidification shrinkage of metal. Typical compositions are shown in (Table 2). Cristobalite expands significantly at temperatures above approximately 200°C and is known as a component of dental investment materials, but because it uses phosphate or gypsum as a binder, it is not suitable for casting titanium or other materials. However, since the magnesia investment material of the present invention does not use the binder, the decomposition gas as described above is not generated. Therefore, even if it contains cristobalite, unlike when conventional dental investment materials are used, the casting will not become unusable due to severe skin roughening and surface hardening. Cap C is obtained by embedding a wax pattern formed in mold M shown in Figure 3 using an investment material of this composition and casting at a mold temperature of 400°C, and cap C obtained by embedding with magnesia cement.
Table 3 shows a comparison of the amount of lifting of the edge when each of the caps C obtained was subjected to a cap test against a mold M. From this (Table 3), it can be seen that the composition of the present invention greatly improves, for example, the adaptability to the above-mentioned mold (regarded as an abutment tooth). Note that the above-mentioned arc casting machine was also used in this experiment.
【表】【table】
【表】
（実施例 ３）
（実施例１）、（実施例２）では、骨材として、
マグネシアを用いたが、アルミナ、ジルコニア、
マグネシア・アルミナを骨材として用いた時も、
カルボン酸塩の前記効果は失われはしないが、ジ
ルコニアは非常に安定であるものの、高価である
こと、焼結強度が低いこと、アルミナは、チタン
に対してマグネシアより不安定であるが、凝固収
縮が少ないことなどから実用的埋没材の骨材とし
ては、マグネシアのみ、マグネシアにアルミナを
加えたもの、マグネシアにマグネシア・アルミナ
を加えたものと考えられる。次に、前記鋳造装置
Ａを用い、これらを骨材として鋳型温度400℃で
チタンを鋳造して得た第４図相応のキヤツプＣの
表面下0.05mmの硬度及び辺縁部の浮き上がり量ｈ
を（表４）に示す。これから判るようにマグネシ
アにアルミナ又はマグネシア・アルミナを添加す
ることにより鋳造物の性状を殆ど損なう事なく、
上記支台歯への適合が改善されることも判る。[Table] (Example 3) In (Example 1) and (Example 2), as aggregate,
Magnesia was used, but alumina, zirconia,
Even when magnesia/alumina is used as aggregate,
The aforementioned effects of carboxylates are not lost, but zirconia, although very stable, is expensive, has low sintering strength, and alumina, although more unstable than magnesia with respect to titanium, is difficult to solidify. Because of its low shrinkage, it is thought that magnesia alone, magnesia with alumina added to it, or magnesia with magnesia/alumina added to it, can be used as aggregates for practical investment materials. Next, using the above-mentioned casting apparatus A, using these as aggregates, titanium was cast at a mold temperature of 400°C.
is shown in (Table 4). As you can see, by adding alumina or magnesia/alumina to magnesia, the properties of the cast material are hardly impaired.
It can also be seen that the fit to the abutment tooth is improved.
【表】
（発明の効果）
以上のように本発明の高温安定型埋没材は、従
来のマグネシア系の埋没材に比し
ａ 硬化時間が速いこと、
ｂ 流動性が改善されること、
ｃ ｂのため鋳型中の水の量を減らし鋳型強度の
増大及び鋳型収縮を少なく出来ること、
ｄ 焼成后に鋳造時にガス化して悪影響を及ぼす
不純物が残らないこと（先行技術のようにアル
カリ金属もしくはアルカリ土類金属のリン酸塩
を使つた場合、1350℃以上でリン酸ガスが出て
チタン等に悪影響を与える）
ｅ 効き方が緩やかであること、即ち添加物の量
が少々変化しても全体の性質は安定的である
（先行技術では添加物の量の微変によつても硬
化時間、流動性が極端に変動する）
ｆ 乾燥時のヒビ割れを軽減することが出来る等
の優れた効果がある。[Table] (Effects of the invention) As described above, the high temperature stable investment material of the present invention has the following properties compared to conventional magnesia-based investment materials: a. Faster curing time; b. Improved fluidity; c. Therefore, the amount of water in the mold can be reduced, increasing mold strength and reducing mold shrinkage, and d) Impurities that gasify during casting and have an adverse effect do not remain after firing (unlike the prior art, impurities such as alkali metals or alkaline earth) (If similar metal phosphates are used, phosphoric acid gas will be emitted at temperatures above 1350℃, which will have a negative impact on titanium, etc.). The properties are stable (in the prior art, the curing time and fluidity fluctuate extremely even with slight changes in the amount of additives). f. It has excellent effects such as being able to reduce cracking during drying. be.
第１図は本発明埋没材のクラツク発生件数と酢
酸マグネシウム添加量とを硬化時間ともども示し
たグラフ、第２図は本発明実施例に於けるチタニ
ウムの真空溶解鋳造装置の一例を示す断面図、第
３図は浮き上りテスト用のキヤツプ金型の形状寸
法図、第４図は浮く上りテストの説明図てある。
（符号の説明）Ａ……アーク発生装置、Ｃ……
キヤツプ、Ｍ……金型、１……アーク柱、２……
電極、３……合金、４……反熱板、５……ルツ
ボ、６……開口部、７……ガイドブツシユ、８…
…通湯口、９……鋳型、１０……テーブル、１
３，１４……電極リード、１５……密壁、１７…
…隔壁、２５……不活性ガスボンベ、２８……キ
ヤビテイ、３３……アーク発生用直流電源、３５
……気密絶縁ブツシユ、３８……溶解室、３９…
…鋳込室。
Fig. 1 is a graph showing the number of cracks in the investment material of the present invention and the amount of magnesium acetate added together with the curing time; Fig. 2 is a cross-sectional view showing an example of a vacuum melting and casting apparatus for titanium in an embodiment of the present invention; FIG. 3 is a diagram of the shape and dimensions of the cap mold for the lifting test, and FIG. 4 is an explanatory diagram of the lifting test. (Explanation of symbols) A... Arc generator, C...
Cap, M...mold, 1...arc column, 2...
Electrode, 3...Alloy, 4...Heat anti-heat plate, 5...Crucible, 6...Opening, 7...Guide bush, 8...
…Throughout, 9…Mold, 10…Table, 1
3, 14...electrode lead, 15...tight wall, 17...
... Partition wall, 25 ... Inert gas cylinder, 28 ... Cavity, 33 ... DC power supply for arc generation, 35
...Airtight insulating bush, 38... Melting chamber, 39...
...Casting room.
Claims (1)
アルミナ（Al2O3）及びマグネシア・アルミナ
（MgO・Al2O3）のうちの１種又は２種以上の材
料を骨材とし、これにアルカリ金属のカルボン酸
塩及びアルカリ土類金属のカルボン酸塩より選ば
れた少なくとも１つもしくは両者の２〜14％（重
量）添加してなる高温安定型埋没材。 ２ 特許請求の範囲第１項に記載した埋没材にお
いてクリストバライトもしくはコロイダルシリカ
のうち１種又は２種を２〜30％（重量）添加して
なる高温安定型埋没材。 ３ 特許請求の範囲第１項又は第２項に記載した
埋没材においてアルカリ土類金属のカルボン酸塩
として酢酸マグネシウムを用いた高温安定型埋没
材。 ４ 特許請求の範囲第１項、第２項又は第３項に
記載した埋没材においてアルカリ土類金属のカル
ボン酸塩として酢酸カルシウムを用いた高温安定
型埋没材。[Claims] 1. Magnesia (MgO), zirconia (ZrO 2 ),
One or more materials selected from alumina (Al 2 O 3 ) and magnesia alumina (MgO・Al 2 O 3 ) are used as aggregates, and alkali metal carboxylates and alkaline earth metal carboxylates are added to the aggregate. A high temperature stable investment material containing 2 to 14% (by weight) of at least one or both selected from acid salts. 2. A high-temperature stable investment material according to claim 1, in which 2 to 30% (by weight) of one or two of cristobalite or colloidal silica is added. 3. A high-temperature stable investment material according to claim 1 or 2, in which magnesium acetate is used as the alkaline earth metal carboxylate. 4. A high-temperature stable investment material according to claim 1, 2 or 3, in which calcium acetate is used as the alkaline earth metal carboxylate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17647886A JPS6333141A (en) | 1986-07-26 | 1986-07-26 | High temperature stabilization type embedding material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17647886A JPS6333141A (en) | 1986-07-26 | 1986-07-26 | High temperature stabilization type embedding material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6333141A JPS6333141A (en) | 1988-02-12 |
| JPH0320292B2 true JPH0320292B2 (en) | 1991-03-19 |
Family
ID=16014369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17647886A Granted JPS6333141A (en) | 1986-07-26 | 1986-07-26 | High temperature stabilization type embedding material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6333141A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3009125B2 (en) * | 1994-11-16 | 2000-02-14 | 株式会社モリタ製作所 | Mold material for high-temperature active metal casting |
-
1986
- 1986-07-26 JP JP17647886A patent/JPS6333141A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6333141A (en) | 1988-02-12 |
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