COPPER ALLOY FOR DENTAL PROSTHESIS

Abstract

The present invention relates to a copper alloy for dental prosthesis and specifically, to a copper alloy for dental prosthesis having such color and luster that the copper alloy can be used as a substitute for a gold alloy and having excellent resistance to corrosion, wherein the copper alloy comprises, in wt %, 7-10% of Al, 1-2.5% of In, 1-2.5% of Sn, 2-4% of Fe, 2-3.5% of Ni, 2.5-4% of Mn, 2-5% of Zn, and the balance Cu.

Claims

1. A copper alloy for dental prosthesis, wherein the copper alloy includes, in wt %, 7-10% of Al, 1-2.5% of In, 1-2.5% of Sn, 2-4% of Fe, 2-3.5% of Ni, 2.5-4% of Mn, 2-5% of Zn and the balance of Cu.

Description

DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a photographic view of a specimen according to one example of the present invention.

[0016] FIG. 2 is a photographic view of a specimen according to a comparative example.

BEST MODE

[0017] The present invention relates to a copper alloy for dental prosthesis which is manufactured by using copper as a main component and adding aluminum, indium, tin, iron, nickel, manganese and zinc therein as an essential composition, and details thereof are as follows.

[0018] If aluminum (Al) is added in an amount of 7 wt % or less, an alloy for dental prosthesis does not turn into a golden color. If Al is added in an amount of 10 wt % or more, the alloy for dental prosthesis turns into a white color. Indium represents the highest fluidity of casting in the range of 1-2.5 wt % and has corrosion resistance which decreases at the upper limit or more.

[0019] If tin (Sn) used to improve corrosion resistance is added in an amount of 1 wt % or less, an addition effect thereof is not obtained. If Sn is added in an amount of 2.5 wt % or more, and the ductility of the alloy is decreased. If iron (Fe) is added in an amount of 2 wt % or less, the strength of alloy for dental prosthesis becomes too low to use. If Fe is added in an amount of 4 wt % or more, the hardness of alloy for dental prosthesis is increased, thereby causing an unpleasant feeling during mastication.

[0020] If nickel (Ni) is added in an amount of 2 wt % or less, fluidity is decreased. When nickel (Ni) is added in an amount of 3.5 wt % or more, elasticity is decreased. Further, if manganese (Mn) is added in an amount of 2.5 wt % or less, an evaporation point is lowered, thereby causing a phenomenon in which a molten metal is burned while boiling. When manganese (Mn) is added in an amount of more than 4 wt %, an alloy for dental prosthesis becomes brittle.

[0021] Zinc (Zn) is used in an amount of 2-5 wt %. At the lower limit or less of Zn, fluidity is decreased so that castability may deteriorate. At the upper limit or more of Zn, hardness and strength are decreased and the alloy turns into a red color.

[0022] Each of the components at the ratio as above is subject into a melting process as follows. First, the components were stacked into a melting pot in the order of copper(iron/nickel/manganese)copper from the bottom thereof, then heated to about 1400 C. to melt down those components as a whole. After confirming that all of them were melt down thoroughly, heating was stopped, after which aluminum/tin/indium/zinc were put thereinto and heated to 1200 C. again. At that time, if a heating temperature is high, gas may be generated so that it is necessary to carefully control the temperature. Once it is confirmed that melting is completed, the resulting molten metal is poured into a mold having a desired shape to be manufactured into a shape of an ingot, a rod, etc., or may be subject to the rolling process to be manufactured into a board, if necessary.

[0023] Hereinafter, the present invention will be described in detail through examples.

EXAMPLE

[0024] A copper alloy for dental prosthesis was manufactured with a composition of alloy as shown is the following Table 1, and then a specimen was manufactured into a crown shape as shown in FIG. 1. FIG. 1 snows a picture of a crown-shaped specimen manufactured with a composition as shown in Example 2.

TABLE-US-00001 TABLE 1 Composition ratio (wt %) of the inventive alloys according to examples Cu Al In Sn Fe Ni Mn Zn Example 1 74.3 8.9 2.0 1.8 3.5 3.0 2.5 4 Example 2 76.8 7.8 1.9 2.0 2.9 2.9 2.8 2.9

Comparative Example

[0025] A copper alloy for dental prosthesis by Aalbadent Inc., USA, which has come into the market, was used as Comparative Example, and the components thereof are as shown in Table 2. As Comparative Example, a specimen was also manufactured into a crown shape as shown in FIG. 2.

TABLE-US-00002 TABLE 2 Composition ratio (wt %) of the alloy according to comparative example Cu Al Fe Ni Mn Zn Comparative 80.7 7.8 2.9 4.3 2.3 2.0 Example

<Color Comparison>

[0026] When comparing FIG. 1 and FIG. 2 with each other, in which the inventive specimen of Example 2 and the specimen of Comparative Example were photographed at the same place and under the same illumination, it may be seen that the specimen of the present invention shows a color close to the golden color. Thus, it may be also seen that the color of the present invention is extremely similar to that of the product which is available in the market as a substitute alloy for gold.

<Corrosion Resistance>

[0027] The results of testing corrosion resistance with regard to five specimens of Examples 1 and 2 and five specimens of Comparative Example are as shown in Table 3.

[0028] A method for testing corrosion resistance is as follows. After preparing a solution in which 22.30.1 g of 35% sodium sulfide (Na2S) was dissolved in 10003 ml of distilled water, the process of immersing the specimen in the solution for 10-15 seconds per minute was repeated for 72 hours. The solution was exchanged every 24 hours. When exchanging the solution, it was determined by visual observation whether there is any corrosion and discoloraton.

[0029] If rust was observed by the visual observation, it was determined that corrosion occurred, and if a change in color was observed, it was determined that discoloration occurred.

[0030] The specimen of Comparative Example did not show any occurrence of rust even in 72 hours later, but it was observed that three specimens are discolored in the form of golden color mixed with a slightly reddish tint. In contrast, it was observed that one specimen is discolored in the specimen of Example 1 out of all the specimens of Examples of the present invention. In the specimen of Example 2, rust and discoloration did not occur. Thus, it was determined that the alloy of the present invention has an excellent effect of corrosion resistance compared to the commercial alloy or Comparative Example.

TABLE-US-00003 TABLE 3 Results of an experiment on corrosion resistance Rust occurrence Discoloration In 24 In 48 In 72 In 24 In 48 In 72 hours hours hours hours hours hours later later later later later later Example 1 None None None None None One discolored Example 2 None None None None None None Comparative None None None None None Three Example discolored

INDUSTRIAL APPLICABILITY

[0031] The present invention can be applied to a copper alloy having a color and luster similar to those of gold and having excellent resistance to corrosion, and the copper alloy of the present invention can be used as a material for dental prosthesis.