JPS60152642A - Palladium-base dental alloy - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Applications] The present invention relates to a palladium-based dental alloy, and specifically to an alloy for use in porcelain fired metal retentates.

[Conventional technology]

Although various alloys have been used over the years as substructures for porcelain fired metal repositories, i.e., the metal substructures attached to veneers, some of the earliest alloys included
Many used gold as the main alloying component along with some amount of platinum or palladium. For example, U.S. Pat. No. 4,123°262 describes a silver-free gold alloy whose composition is about 50 to 50 gold by weight.
8%, 05-105% indium, 05-85% tin, or 10-3.0% gallium and the remainder palladium. A similar gold alloy is also described in U.S. Pat. No. 4,205,982, with the composition, by weight, of approximately 45-6.4% gold, 30-50% palladium, and 2-20% tin. 7%, zinc or indium or mixtures thereof 3-10%, and rhenium or nickel or platinum or mixtures thereof as grain-refining component O-2%.

Incidentally, in recent years, as the prices of gold and platinum have increased and fluctuated, extensive efforts have been made to significantly reduce the gold content of such alloys (e.g., U.S. Pat. No. 4,179,288). Although there are obvious economic benefits to using less gold, the physical properties of the alloy are often sacrificed to achieve these economic benefits.

Additionally, various attempts have been made to replace gold with silver, nickel, cobal F1 copper, and other elements that are significantly cheaper than gold in producing such alloys. However, the use of these elements in place of gold poses a number of new problems. For example, silver discolors the porcelain fired onto it, nickel is considered an oral allergen in some people, and cobalt and copper are darker than the desired oxides. It is known that it causes

Therefore, alloys with high gold content remain the standard, and quality comparisons are made based on gold content.

[Problem that the invention seeks to solve]

This invention has been made to solve the drawbacks and problems of the prior art described above. Namely, ■) the provision of an economical palladium-gold alloy that has all the economic advantages of alloys with low gold content, but also has physical properties comparable to alloys with high gold content; and 2) providing an economical palladium-a-gold alloy that has thermal properties superior to gold-rich alloys and therefore can be used with a wider range of commercially available porcelain materials than gold-rich alloys; 3) Providing an economical palladium ψ gold alloy that does not contain silver, nickel, copper, or cobalt; and 4) It melts better and has a higher rigidity so that the limit binding and compatibility are higher than that of gold. 5) providing an economical palladium-gold alloy that is better than alloys with higher content; and 5) an economical palladium-gold alloy with an excellent crystal grain structure and not prone to hot tearing during the investment casting process. and the provision of alloys.

[Means to solve the problem]

8 by reducing the gold content to less than half that of the conventional alloy.
~25% by weight and up to 10jTi% gallium was used. Naturally, silver, nickel, steel and cobalt were not used, and the casting of the alloy was carried out in a protected environment.

[For production]

Obviously, reducing the gold content to less than half that of prior art alloys would solve the economic disadvantage;
The gold content is between 8 and 25 wt.% and the use of up to 10 wt.% gallium does not sacrifice physical properties as would occur if the gold content was reduced to about 5 wt.% or less. Gallium acts very effectively in lowering the melting point of palladium and helps it reach physical properties comparable to gold-rich alloys.

Preparation of the alloy under a protected environment resulted in an excellent grain structure of the alloy and no absorption of gases by the alloy.

〔Example〕

The palladium-based dental alloy according to the invention comprises:
The following elements, i.e. elements based on the following weight %: Gold 8-25 Gallium 0-10 Boron 0.05-0.25 Rhenium 0.1-05 Indium and Oζ/or Tin O-20 Zinc O~
4 and the remaining weight percent palladium, where the weight percent palladium is:

That is, when a mixture of gallium and indium and/or tin is added to the alloy, the amount of gallium present is about 4
When the amount of gallium and indium and/or tin is equal to or less than 4% by weight, the total percentage of gallium and indium and/or tin ranges from 12 to 20%, but if the amount of gallium present is approximately 4% by weight or more and 10% by weight %, the total type of gallium and indium and/or tin ta% is in the range of about 8 to 20, and when a mixture of zinc and indium and/or tin is added to the alloy, the amount of zinc present is present in place of gallium in an amount of 4% by weight or less.

Therefore, the alloy has a yield strength of 50,000 PS (or more), an ultimate tensile strength of 60,000 PS or more, an elongation of 10% or more, and a melting point of 2,200 to 2
, 400°F (1,204-1,316°C).

The alloy is cast with approximately 8 to 25 wt% gold added, and in this case, not only can the economic benefit obtained by reducing the gold content by a considerable amount, but also the gold It has been found that the physical properties of the alloy are not sacrificed as occurs when the content is reduced below about 5% by weight.

Although gallium can be optionally used, it is preferred to use gallium in the range of about 4-10% by weight;
The reason is that gallium is very effective in lowering the melting point of palladium and helps it reach physical properties comparable to alloys with higher gold content. If desired, indium or tin or a mixture of indium and tin can be used in place of gallium, but since neither indium nor tin is as effective as gallium in lowering the melting point of palladium, up to about 20% ffi. of indium or tin or a mixture thereof must be used in place of gallium. Preferably, about 15 to 20 indium and/or tin
It should be used within a range of % by weight. If desired, mixtures of gallium, indium, and tin may be used, provided that the amount of gallium present is less than or equal to about 4% by weight or equal to the sum of gallium and indium and/or tin. The weight percent ranges from about 12 to 20, but if the amount of gallium present is greater than about 4 weight percent to 10 weight percent, gallium and indium and/or
Or the total weight percent of tin ranges from about 8 to 20. It has been found that good results can be obtained when zinc is used in combination with indium and tin instead of gallium, but in this case no more than about 4% by weight of zinc is used in such a mixture. It must be noted that zinc and gallium should never be used together;
Alloys tend to form low melting phases during porcelain installation operations. The effect produced by the use of these additives is to increase the melting point of the alloy by 2,200 to 2,400° fi' (1,20
4 to 1,316° C.) and adjust the physical and thermal properties. Additionally, these additives create soakable oxides that create chemical bonds within the porcelain-fired metal composite.

Boron is added to the alloy in the range of about 0.05 to 0.25% by weight, with a preferred amount in the range of 0.05 to 0.1% by weight, which melts the boron. and to serve as a degassing agent for oxygen absorbed by the alloy during the casting process. If the amount of boron used exceeds 0.25%, the alloy becomes too brittle for use in the dental field.

About 0.1 to 0.5% rhenium is used to refine the grains of the alloy. Alloys are made up of individual crystal grains that are in contact with each other, and the grain size determines the physical properties of the alloy. The grain size can vary from coarse to fine, and the grains can be regular or irregular. Ideally, there are equiaxed grains, which are obtained by grain refinement. Alloys with this type of crystal grain structure have excellent elongation, tensile strength and tenacity. Such alloys have less tendency to undergo hot σ1 cracking during investment casting processes when compared to alloys with a coarser grain structure. Hot cracking, as understood in this art, involves the formation of cracks within a disturbed object due to the stresses generated within the cast object as it cools during the investment casting process. . These cracks result in the formation of a fracture surface, requiring the casting to be remade, thus resulting in a loss of time, energy and materials needed to make the original casting. .

If desired, up to about 2% of the noble metals palladium and gold can be replaced with any of other noble metals such as platinum, iridium or ruthenium.

Preferably, the alloy is 15% gold and 76% palladium by weight.
65% by weight, 8% by weight of gallium, 0.05% by weight of boron, and 0.3% by weight of rhenium.

The refined grained alloys of this invention must not be prepared by conventional techniques, ie, by exposure to air. The reason for this is that preparation using conventional techniques results in the formation of air bubbles within the porcelain during the porcelain firing process. More precisely, the grained alloy must be prepared under a protective environment such as a vacuum or a reducing atmosphere or an inert elevated atmosphere, such as an argon atmosphere. If this is not done, the alloy will absorb gases from the atmosphere and during firing the gases will be released from the alloy and form bubbles within the porcelain. It has been found that crucibles containing carbon are unsuitable for preparing the alloys of this invention. To be more precise, a ceramic crucible, such as a zirconia crucible, is preferred.

If argon is used as the H ring sulfur, it is preferred to apply a vacuum to the melting chamber to remove ambient air, and then
argon is introduced into the melting chamber. Alternatively, argon can be passed through the melting chamber without first applying a vacuum.

When only vacuum is used, the temperature of the melt and the vacuum used must be adjusted taking into account the vapor pressure of the alloying components; This is to prevent extreme relative losses. In particular, when zinc is included in the alloy, a protective environment consisting of a reducing or inert gas rather than a vacuum environment is used when preparing the alloy, taking into account the relatively high vapor pressure of zinc. must be used.

The table below shows two further examples of this invention, but these specific alloys are not intended to limit the scope of this invention. All alloying constituent elements are expressed in weight percent. All of the alloys listed below exhibited a fine equiaxed grained structure.

For comparison, a typical gold-rich alloy consisting of 5075% gold, 40.0% palladium, 7.5% indium, and 1.75% gallium is Characteristics of blowing, i.e. yield strength 72゜000P
It exhibited an SiX ultimate tensile strength of 102,000 I'Si and an elongation of 24%.

Table 1 81.65 10 8 0.05 0.32 76
．． 65 15 8 0.05 0.3 Characteristics (51) 1 65.000 90,000 242 80.00
0 100,000 2515- (Note 1) Properties measured after a simulated porcelain firing cycle. That is, the properties of the above alloy are 1 at room temperature.
, placed in a furnace maintained at 200°F (649°C) and heated to 100°C.
At a rate of 1,850°F (1,850°F) per minute, the alloy
The alloy was then cooled to room temperature and this heating and cooling cycle was repeated a total of five times before measurements were taken.

As previously explained, the alloys of this invention are prepared in a protected environment such as a vacuum or a reducing or inert atmosphere, such as an argon atmosphere. In other words, since the alloy of the present invention does not absorb gases from the atmosphere during preparation, it does not release gases and form bubbles within the porcelain during the porcelain firing process. Therefore, the palladium-based dental alloys recited in claims 1 to 9 can be made into essentially bubble-free dental porcelain by baking porcelain into each of these alloys. The material can be baked to form a metal recovery product.

〔Effect of the invention〕

As explained above, the dental alloy based on Balaji-16-ram according to the present invention has a gold content of about 8 to 25% by weight, which is less than half that of this type of alloy according to the prior art.
Binding, silver, nickel, cobalt and copper free, 10
Addition of gallium up to % by weight, instead of gallium,
Alternatively, indium and/or tin may be added together with gallium, zinc may be added in combination with indium and/or tin instead of gallium, boron and rhenium may be added, and vacuum or a reducing or inert atmosphere, such as argon Since it is manufactured under a protective environment such as an atmosphere, the following effects can be obtained.

b) It is possible to secure economic benefits without sacrificing the physical properties of the alloy. This is due to the fact that the gold content is reduced to less than half of that of this type of alloy according to the prior art, to approximately 8-25% by weight, and that gallium is incorporated at up to 10% by weight JIk.

Oral) Solve the problems of conventional technology such as discoloration of porcelain, the effect of allergens in the oral cavity, and the dark color of desirable oxides. This is because nickel, cobalt and copper are not added.

c) It has better thermal properties than prior art alloys with high gold content. This is because gallium is very effective in lowering the melting point of palladium, and indium and tin also lower the melting point of palladium. Therefore, the rigidity of the alloy is increased, and the critical cohesion and compatibility are improved.

2) The grains of the alloy are refined to have an excellent grain structure of equiaxed crystals, so that hot tearing does not occur during investment precision casting. This is due to the addition of rhenium and also because boron serves as a degassing agent for oxygen absorbed by the alloy during the melting and casting process.

e) A dental porcelain fired metal retentate essentially free of air bubbles can be constructed by firing the porcelain.

This is because the alloys of this invention are prepared under a protected environment.

19-

Claims (1)

[Scope of Claims] (11) The following elements based on the following weight %: Element Weight % Gold 8-25 Gallium O-10 Boron 0.05-0.25 Rhenium 0.1-0. 5 Indium and/or Tin O~ 20 Zinc O~
4 and the remaining palladium, and the palladium is such that when a mixture of gallium and indium and/or tin is added to the alloy, the amount of gallium present is about 4% by weight or less. or about 4% by weight, the total weight% of gallium and indium and/or tin is about 12% by weight.
20 to 20, but the amount of gallium present is about 4% by weight
In the case of up to 10% by weight from the above, the total weight% of gallium and indium and/or tin is in the range of about 8 to 20, and when a mixture of zinc and indium and/or tin is added to the alloy, zinc and the zinc is present in the alloy in place of gallium, the alloy has a yield strength of 50,000 P8.
s or more, the ultimate tensile strength is 60,000 Psi or more, the elongation is 10% or more, and the melting point is 2.20 Psi or more.
0 to 2,400°F (1,204 to 1,316°C)
A palladium-based dental alloy characterized by: (2) The palladium-based dental alloy according to claim 1, wherein the gallium has a weight percent of about 4 to 10. (3) The following elements based on the following weight %: Element Weight % Gold 8-25 Boron 0.05-0.25 Rhenium 0.1-0.5 Indium and/or Tin 15-20 Palladium This alloy has a yield strength of 50,000
PS< and the ultimate tensile strength is 60,000 PS
i or more, elongation rate is 10% or more, and melting point is 2
200 to 2,400°F (1,204 to 1,316
A palladium-based dental alloy characterized by a temperature of (4) the elements are less than or equal to about 4% by weight in place of comparable amounts of indium and/or tin;
A dental alloy based on paranym according to claim 3, characterized in that gallium is incorporated in an amount equal to % by weight. (5) The element according to claim 3, characterized in that zinc is added in an amount of about 4% by weight or less instead of a comparable amount of indium and/or tin. Dental alloy based on palladium. (6) The amount of boron is about 0.05 to 01% by weight.
A palladium-based dental alloy according to claim 1, characterized in that the palladium-based dental alloy is (7) Palladium-based dental alloy consisting essentially of the following elements in weight percent, i.e., element weight percent Gold ] O Palladium 81.1'i 5 Gallium 8 Boron 0.05 Rhenium 0.3 . (8) A palladium-based dental alloy consisting essentially of the following elements in weight percentages: 15 gold, 76.65 palladium, 8 gallium, 8 boron, 0.05 rhenium, and 0.05 rhenium. (9) The palladium-based dental material according to claim 1, wherein up to about 2% by weight of the palladium and/or gold is replaced by platinum, iridium or ruthenium. alloy.