JPH01215938A - dental palladium alloy - Google Patents

Abstract

PURPOSE:To obtain the high strength, high elastic rate, high elongation and suitable melting point of the title alloy and to increase the bonding strength thereof with a ceramic material by specifying the contents of Cu, Sn and Ge. CONSTITUTION:The alloy consisting of, by weight, 5-15% Cu, 8-18% Sn, 0.5-4% Ge and the balance constituted of Pd is refined. Total 0.001-5% of one or more kinds among In, Fe and Co are furthermore added to the above compsn. at need. By such constitution, a Pd alloy for dental use having high alloying strength, high elastic rate and suitable high elongation and having high bonding strength with a ceramic material and suitable melting point can be obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention provides a novel palladium alloy for dental use.

[Prior art and problems to be solved by the present invention]

A dental palladium alloy is an alloy used for baking dental porcelain, and the porcelain baking alloy is a metal used to make the base portion of metal-baked porcelain, which is a type of dental prosthesis. Furthermore, metal-baked porcelain is a prosthesis in which porcelain is bonded onto a metal base. The method for joining porcelain and metal substrate is
- For boat fishing, first a metal base is held at high temperature to form an oxide film on the surface of the metal base, and then a mud-like material made by dissolving porcelain powder in water is built up on the metal base covered with the oxide film. This method involves drying, firing at a high temperature, and simultaneously bonding to the metal substrate. Therefore, dental alloys, especially alloys for porcelain baking, not only have the strength, corrosion resistance, and biocompatibility required of dental alloys, but also have a coefficient of thermal expansion that matches that of porcelain. It is required to have strong bonding, high high temperature strength, high strength, high elastic modulus, and resistance to deformation.

The currently used porcelain baking alloy is Au-pt-p
Noble metal alloys mainly composed of d or Au-Pd-Ag are mainstream. However, the noble metal alloy has problems in that Au and PT are expensive and economically disadvantageous, and the alloy strength is insufficient. Therefore, a Pd-based alloy that solved these problems was developed and proposed (Japanese Unexamined Patent Publication No. 5
9-28545 or p containing pd-Cu-G a as the main component as shown in JP-A No. 61-186437.
d Made of gold alloy. These PD gold alloys containing Cu and Ga as the main additive elements are relatively low priced, have high strength, and high corrosion resistance.

It is an excellent alloy in that it is less harmful to living organisms. However, since this alloy is hard and relatively brittle, it may break when a large external force is applied to it in practice, and it is difficult to process such as grinding or rolling. Although its properties are good, its high temperature strength is not sufficient.
There is a problem in that deformation tends to occur during heat treatment including pretreatment for joining porcelain materials, and it has the disadvantage that it is not suitable for dental prostheses that require precision.

Furthermore, in Japanese Patent Application Laid-Open No. 61-295348, 'palladium 6
0-80%, total 0-8%, platinum 0-5%, ruthenium and/or rhenium θ-1, copper 2-20%, tin and/or indium 1-12%, tungsten, molybdenum, niobium and tantalum One or more elements of 0.
``Material for dental porcelain welding'' using a silver-free palladium alloy with a composition consisting of 2-5% and cobalt θ-15%, the total content of tin and indium must be 5-14% The above-mentioned materials are excellent in that they have high strength and relatively large elongation, and their melting points are not too low.

However, since this material has a relatively low modulus of elasticity, it produces relatively large strains when external forces are applied.

Therefore, if an external force is applied to the porcelain bonded to the material, there are cases where the porcelain material, which does not show any elongation, cannot withstand the strain and cracks, so there is still room for improvement. Ta.

[Means for solving problems]

The present inventors have developed an alloy with high strength, high elastic modulus, moderately large elongation, high bonding strength with porcelain, and a suitably high melting point that does not impair workability. We have been conducting extensive research in order to obtain a dental alloy that is free from the above-mentioned problems and is less deformed by heat treatment. As a result, the present invention was completed.

That is, in the present invention, copper 5 to 15% by weight; tin 8 to 18% by weight:
A dental palladium alloy consisting of 0.5 to 4% by weight of germanium and the balance palladium.

' Further, the present invention provides a total of 5 to 15% copper, 8 to 18% tin, 1% germanium, and at least one selected from the group consisting of indium, iron, and cobalt, in a total of 0.001 to 1% by weight. A dental palladium alloy comprising 5% by weight and the balance palladium is also provided.

In the dental alloy of the present invention, the components constituting the alloy and their composition ratios are extremely important requirements for achieving the object of the present invention.

One of the components constituting the alloy of the present invention is copper. The copper (
Cu, ) is effective in adjusting the melting point and thermal expansion coefficient of the resulting alloy, improving the alloy strength, and forming a dense external oxide film that has good wettability with porcelain. It is preferable that the copper be present in an amount of 5 to 15% by weight in the alloy.

If the copper content is less than 5% by weight, the melting point will be high, resulting in poor workability, and the alloy strength will be low, making it impractical. On the other hand, if the copper content exceeds 15% by weight, the outer oxide film will become thicker and the adhesion to the alloy base will deteriorate.
This is not preferable because it leads to a decrease in the bonding strength with the porcelain material, and the color of the external oxide film becomes black, impairing aesthetics.

Another component constituting the alloy of the present invention is tin (Sn). Very effective results can be obtained by adding tin and germanium in a specific proportion.

That is, in the alloy, tin is contained in an amount of 8 to 18% by weight, preferably 10 to 1% by weight.
High strength by containing a relatively large amount of 5% by weight and coexisting with germanium.

High modulus, large elongation and suitable melting point are obtained. In addition, tin has the effect of adjusting the coefficient of thermal expansion, and furthermore, it forms an internal oxide layer just below the alloy surface, controls the thickness of the outer oxide film of copper, which will be described later, and improves the bond between the outer oxide film and the alloy base. It has the effect of increasing If the tin content in the alloy is less than 8% by weight, the alloy strength will decrease and the melting point will become high, making it difficult to cast.In addition, the internal oxide layer will be incomplete and the external oxide layer will deteriorate. This is not preferable because it becomes difficult to control the thickness appropriately and the bonding strength with the porcelain material decreases. On the other hand, if the tin content in the alloy exceeds 18% by weight, this is undesirable since it will have an adverse effect on the external oxide film, lowering the bonding strength with the porcelain, and causing the alloy to become brittle.

Yet another constituent of the alloy of the present invention is germanium (
Go). The germanium in the alloy of the present invention is 0
．． It is preferably contained in a range of 5 to 4% by weight. The excellent effects of the present invention are exhibited by the coexistence of germanium with tin, which is present in a relatively large amount as described above.

Namely, by adding a small amount of germanium (Ge), it has the effect of increasing alloy strength 2 elastic modulus without embrittling the alloy, moderately lowering the melting point, improving the properties of the molten metal during melting, and improving castability. There is.

Furthermore, the above-mentioned internal oxide layer is made finer and denser, and the thickness and properties of the outer oxide film, which will be described later, can be more optimally controlled.

If the amount of germanium contained in the alloy is less than 0.5% by weight, it will be difficult to achieve the above effects, whereas if it exceeds 4% by weight, the alloy will tend to become brittle, which is not preferable.

In the alloy of the present invention, the balance of each of the above components and composition ratios is palladium (Pd). Palladium is the base element of the alloy of the present invention, and is the basis of all the properties of the alloy of the present invention, and plays an important role in particular in increasing the corrosion resistance of the alloy.

The alloy proposed in the present invention containing specific amounts of copper, tin, and germanium, with the remainder being palladium, has many excellent properties as a dental alloy, as described above. In order to further improve such properties, it is often preferable to further include a specific amount of at least one component selected from the group consisting of indium, iron and cobalt.

Indium (In) has the effect of improving the alloy strength and forming a fine internal oxide layer by interacting with the tin, thereby controlling the thickness and properties of the external oxide film more optimally. Further, iron (Fe) and cobal (Co) have the effect of improving the alloy strength and becoming constituent elements of the outer oxide film, increasing the bonding strength with the porcelain and lightening the color of the outer oxide film. It also has the effect of increasing the coefficient of thermal expansion, and can be used with porcelain materials with higher coefficients of thermal expansion.

The indium, iron and cobalt mentioned above may be contained as one component, two components or three components in the alloy of the present invention, if necessary. The at least one component selected from the group consisting of indium, iron and cobalt is present in the alloy in an amount of up to 5% by weight.
It is preferable to keep the content up to. Generally, it is suitable to contain this component in a range of 0.001 to 5% by weight. If the content of this component exceeds 5% by weight in the alloy, the alloy tends to become brittle, which is undesirable.

The method for producing the alloy of the present invention is not particularly limited. In general, for example, alloy components of the invention such as PcL Cu+
Sn+ Get Inn Co and Fe are used as raw materials, including a single element or a master alloy prepared by pre-alloying two or more selected from these element groups, and these are heated in vacuum, inert gas, or air. Regardless,
Alloying may be performed by any melting method such as arc melting, high frequency melting, in-furnace melting, etc.

Generally speaking, the order of melting is to start by melting the raw materials that are large in amount, have a moderate melting point, and are not particularly active, and then add smaller amounts or more active raw materials one after another. In the alloy of the present invention, for example, pd, Co, Fe, Cu
, Sn, Ge, and In are added and melted in this order, but the order is not limited to this, and two or more types of raw materials may be added at the same time. They may be melted all at once. Alternatively, it may be produced by a powder metallurgy method in which powders of individual elements or raw material powders including mother alloy powders are mixed and then fired and sintered.

〔Effect of the invention〕

The alloy of the present invention exhibits excellent functionality for any porcelain. Especially for dental porcelain, for example, 5in2 is 40 to 70
Weight% 1A1203 is 10-20% by weight, 20 is 1-20% by weight
10 weight 1Na20 is 3-7 weight t%, 8nO2 is θ~1
5 Creation I.

CaO is θ~7iffi%, ZrO is 0~5% by weight.

T10□ is 0 to 3% by weight, B2O3 is θ to 10% by weight,
It exhibits excellent functionality for frit glass having a composition of 0 to 1% by weight of ZnO.

The alloy of the present invention also has high strength and high modulus.

It has large elongation and appropriate melting point, and has high bonding strength with porcelain. Furthermore, the alloy of the present invention satisfies various physical properties generally required of dental alloys, and can be used for prosthetics such as cast crowns and bridge dentures that can be maintained safely and stably in the oral cavity for a long period of time.

It can be used for denture bases, and is also an excellent alloy for dental materials such as biomaterials such as artificial bones and implants.

〔Example〕

EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. Further, the results of each example and comparative example are summarized in Table 1, including the composition, melting point, hardness, tensile strength, elongation 2 modulus of elasticity of each alloy, and bonding strength between the alloy and the porcelain. The respective measurement methods are as shown below.

1) Melting point of alloy The liquidus temperature of the alloy measured by a thermal analyzer (DTA) was taken as the melting point.

2) A plate-shaped specimen with an alloy strength of 1ONxX10n+ was cast, and the surface was polished to a mirror finish.
The measurement was carried out under the conditions of 0 g and a holding time of 15 seconds.

3) Tensile strength, elongation, and elastic modulus of the alloy After casting a rod-shaped test piece with a diameter of $23 inches and a gauge distance of 15 m, and finishing the surface with emery paper #1500,
This was tensilely broken, the tensile strength at break was taken as the tensile strength, and the elongation rate between the gauge points at this time was taken as the elongation. Further, the elastic modulus was determined from the stress-strain curve obtained by this test.

4) Bonding strength between alloy and porcelain After polishing the surfaces of two test pieces with a length of 25 m, a width of 6 m, and a thickness of 1 u to a mirror finish, they were heated in the atmosphere at 980°C for 5 minutes to cause oxidation on the alloy surface. A film was formed. Next, opaque porcelain manufactured by VITA (VMK68.51
1. A2) was placed on the test piece so that the thickness was 0.1 mm, and sandwiched between the other test pieces. In addition, the two test pieces are
They were stacked horizontally in opposite directions. After drying the porcelain, the stacked test pieces were placed in an electric furnace at 800°C.
The porcelain and specimen were baked in a vacuum at a temperature of 980°C at a rate of 5°C per minute. Both test pieces were pulled horizontally in opposite directions using a tensile testing machine to cause them to break, and the average stress at this time was taken as the bonding strength between the porcelain and the metal.

Claims (2)

[Claims] (1) A dental palladium alloy consisting of 5 to 15% by weight of copper; 8 to 18% by weight of tin; 0.5 to 4% by weight of germanium and the balance palladium. (2) 5-15% by weight of copper; 8-18% by weight of tin; 0.5-4% by weight of germanium; a total of 0.001-1% of at least one selected from the group consisting of indium, iron, and cobalt.
A dental palladium alloy consisting of 5% by weight and the balance being palladium.