KR100630505B1 - Dental casting alloy - Google Patents

Abstract

The present invention is a Ni-Cr-Mo-based dental casting alloy containing 64 to 70% by weight of Ni, 17 to 20% by weight of Cr, and 5.5 to 7.5% by weight of Mo, wherein the alloy for dental casting is Co 3 To provide a dental casting alloy further comprises ~ 6% by weight, Ti 3-5% by weight, Si 1-3% by weight, the present invention is allergic, toxic, or carcinogenic in the oral environment and other It is a very useful invention that can provide dental casting alloys that are excellent in corrosion resistance and biological stability, good biocompatibility, and mechanical and mechanical properties in the oral cavity without using Be, which includes various problems. will be.

Nickel base, dental, casting, alloy

Description

Dental casting alloy for ceramic material parts

Figure 1-Microstructure photograph of the present invention As-cast specimen.

Figure 2-microstructure photograph of conventional commercial alloy As-cast specimens.

Figure 3-microstructure photograph of the present invention homogenization heat treatment specimen.

Figure 4-microstructure photograph of a conventional commercial alloy homogenization heat treatment specimen.

5-EDS analysis of the present invention specimens.

6-Rockwell Hardness (HRA) measurement results of the present invention specimens.

Figure 7-Rockwell hardness (HRA) measurement results of conventional commercial alloy specimens.

8-Melting temperature section of the specimen of the present invention.

9-melting temperature range of conventional commercial alloy specimens.

Figure 10-Corrosion test results of the specimen of the present invention.

Figure 11-Corrosion test results of conventional commercial alloy specimens.

The present invention relates to an alloy for dental casting, and more particularly to an alloy for dental casting having better mechanical properties, corrosion resistance, and melting point properties than conventional dental casting alloys.

In general, the dental casting alloy refers to an alloy used for various prosthetic materials such as inlays, crowns and cores to restore the chewing function and shape of damaged teeth. And non-noble metal alloys, which are classified for filling and prosthetic purposes according to their purpose, and for casting and processing, depending on their usage.

The metal or alloy used for the dental casting should not have any chemical properties that, among other things, physiologically harmful to patients or professionals, no change in physical or chemical properties in the oral cavity, It is difficult to have technical difficulties in manufacturing or use that are unwieldy.

In addition, mechanical and physical conditions such as strength, conductivity, melting temperature range, thermal expansion coefficient, etc. should be suitable, the application range should be wide for each device, and related materials such as metals and alloys should be quantitatively rich to make them easy to manufacture. In addition, for economics, the price must be relatively inexpensive and must be easily available in an emergency.

In the case of dental casting alloys, Au-based alloys are widely used, which have little influence on the human body. However, Au is expensive and aesthetically unfavorable. Ni-Cr-based and Co-Cr-based alloys having various advantages, such as high resistance, which can reduce the thickness of the metal of the ceramic field, are used. However, in the case of Ni-Cr based alloys, the development of products without Be is more urgently needed than ever due to the toxicity of added Be. However, there are not many studies on the development of products without Be.

Among the Ni-based alloys, one of the most important alloys for porcelain-fused-to-metal (PFM) firing and crown, processed dentures and partial dentures is Ni-Cr-Mo casting alloy. As the Ni-Cr-Mo casting alloy, Cr is added to increase the corrosion resistance of the alloy, and Mo is added to increase resistance to local corrosion such as formula and crevice corrosion. Be is added to improve the castability of the alloy by improving the castability of the alloy and to promote the formation of oxides, thereby improving the adhesion to the porcelain. The Be is due to problems of toxicity, potential carcinogenicity and hypersensitivity to corrosive products. Its use is being rejected.

The prior art for the range of compositions of the current casting alloy is as shown in the table below.

Table 1 shows the composition range of the dental casting alloy patented in Korea.

Table 2 lists the compositions of the dental casting alloys patented in the United States.

Table 3 shows the composition range of the dental casting alloy patented in Japan.

The present invention uses Ni-Cr-Mo cast alloys, but the corrosion resistance and biological stability in the oral cavity without the use of Be, which includes the problems of toxicity and potential carcinogenicity, hypersensitivity to corrosion products to the human body Not only is this good and biocompatible but also its mechanical and mechanical properties are to provide a dental casting alloy that is most similar to a living body.

To this end, in the present invention, Ni-Cr-Mo-based alloys were designed by adding Co 3-6 wt% and Si and Ti alone or in combination with Ni-Cr-Mo-based alloys.

At this time, Ni is added to the base composition of the present invention casting alloy 64 to 70% by weight, Cr is added to passivate the non-noble metal alloy and thereby increase the corrosion resistance, but adds 17 to 20% by weight. At this time, less than 17% by weight of the corrosion resistance is inferior and 20% by weight or more in the solid solution to Ni to improve the strength, but the metal-ceramic adhesion ability is lowered.

Mo is added in the range of 5.5 to 7.5% by weight in order to improve the mechanical properties such as strength and thermal expansion by strengthening the solid solution, and to resist the corrosion and corrosion of Ni-based alloys, but less than 5.5% by weight is insufficient in corrosion resistance and insufficient mechanical strength. If more than 7.5% by weight, the workability problem of the alloy occurs.

Co is added in consideration of the melting point lowering effect, the improvement of mechanical properties, and the corrosion resistance, but less than 3% by weight has a low melting point strengthening effect, and more than 6% by weight deteriorates the mechanical properties. .

In addition, Ti is added to improve mechanical properties and ceramic materials, but less than 3% by weight is less effective in improving the mechanical properties, and more than 5% by weight may deviate from the target mechanical properties. Weight percent.

Si is added in order to control Cr oxide layer and improve castability and mechanical properties, in which less than 1% by weight has little effect on castability, and more than 3% by weight may deviate from the target mechanical properties. Is 1-3 wt%.

Components and effects of each composition added for the production of the Ni-Cr-Mo-based dental casting alloy are as follows.

Ni is an atomic number 28, atomic weight 59, melting point 1445 占 폚, group 8b element, and its crystal structure is room-centered cubic crystal (fcc) at room temperature. Ni employs about 35% by weight of Cr, about 20% by weight of Mo and W, and about 5-10% by weight of Al, Ti, Mn, and V. Metallic stability, resistance to reducing acids and alkalis, stress corrosion resistance The cracking property is improved. However, there is a need for improvement of cytotoxicity such as soft tissue inflammation, carcinogenicity, and allergic reactions such as contact dermatitis.

Cr is an atomic number 24, an atomic weight of 52, a melting point of 1800 ° C., and a group 6b element. The crystal structure is body centered cubic crystal (bcc) at room temperature. Cr is an element added to passivate non-noble metal alloys and thereby increase corrosion resistance, and is a reactive metal that forms a strong and stable oxide film in contact with air or water. In addition, it improves oxidation resistance and sulfidation resistance, increases resistance to halogen or high temperature halogen compound at 18 wt% or less, and improves corrosion resistance in water. Cr or Si layer control is possible when Si or Al is added.

Mo is atomic number 42, atomic weight 96, melting point 2625 ℃, group 6b element. The crystal structure is room-centered cubic (bcc) at room temperature, and a small amount is added to improve mechanical properties such as strength and thermal expansion. Significantly increases resistance to, and increases resistance to reducing acids.

Co is an atomic number 27, atomic weight 59, melting point of 1390 ° C, group 8b. The crystal structure is dense hexagonal (hcp), and the corrosion resistance of Co is similar to Ni in most environments and is cytotoxic. Significantly increases resistance to crevice corrosion and resistance to reducing acids. In addition, Co is added to Ni-based alloys to increase the solubility of C, to improve strength, solidification resistance, and thermal expansion by solid solution strengthening.

Ti is an atomic number 22, atomic weight 48, melting point 1670 ° C, group 4a element, and the crystal structure (α type) at room temperature is a dense hexagonal crystal (hcp), for deoxidation purposes or to bond and fix C and / or N, respectively. A small amount is added in the corrosion resistant alloys. In addition, Ti forms a solid solution hardening and an intermetallic compound Ni3Ti to improve mechanical properties by age hardening.

Si is an atomic number 14, atomic weight 28, melting point 1410 ° C, group 4b, and the crystal structure at room temperature is diamondcubic lattice (hcp), to improve castability, or to form an oxide as a bonding medium with ceramics. Small amount is added.

This will be described in more detail by the following examples.

Example 1

An alloy of 70% Ni-20% Cr-7% Mo-3% Co composition to which 70% by weight of Ni, 20% by weight of Cr, 7% by weight of Mo, and 3% by weight of Co was added was used as the base alloy 3Co, and Si was An alloy sample was prepared by adding 2 wt% and 4 wt% Ti.

Example 2

An alloy of 70% Ni-20% Cr-7% Mo-6% Co composition containing 70% by weight of Ni, 20% by weight of Cr, 7% by weight of Mo, and 6% by weight of Co is used as the base alloy 6Co, and Si is An alloy sample was prepared by adding 2 wt% and 4 wt% Ti.

After the alloy sample and the imported commercial alloy sample of the composition designed as in Example 1 and Example 2 were arc-dissolved under Ar gas atmosphere and homogenized and heat treated at 1000 ° C. for 3 days, the microstructure was composed of an optical microscope and an electron microscope. By EDS, hardness is determined by Rockwell hardness tester, compressive strength is used by tensile tester, melting temperature section is DTA, thermal expansion coefficient is TMA, and corrosion resistance and biocompatibility are measured by Potentiodynamic Polarization Test and It was examined by Cytotoxicity Test and compared with the result of imported commercial alloy as a comparative example. The obtained result is as follows.

As described above, the microstructure of the As-cast alloy of each specimen to be examined showed dendritic structure of all specimens, as shown in FIGS. 1 and 2, and an alloy designed according to the present invention, that is, Example 1 and Example The alloy of 2 had a slightly coarse shape compared to the imported commercial alloy as a comparative example. The microstructure of the homogenized heat-treated alloy exhibited a pseudo dendritic or dendritic structure as shown in FIGS. 3 and 4, and all of the example alloys showed an austenite single phase.

In addition, the distribution of components in the grains and grain boundaries did not differ significantly between the components of Examples 1 and 2, but 3CoSiTi alloys, 6CoSi alloys, and 6CoSiTi alloys commonly exhibit high values of Mo and Si in the dendrite phases. The distribution of components at and grain boundaries was opposite, and segregation tendency of Mo and Si was high between dendrites.

As shown in FIGS. 6 and 7, hardness of both Examples 1 and 2 was lower than that of the comparative example, and the 3CoSiTi alloy in which Si and Ti were added to the alloy of Example 1 was 66HRA and 6Co alloy. The 6CoSiTi alloy with Si and Ti composite was rapidly increased to 65HRA, and the Si and Ti composite additive effect was very high, and the results were almost the same as that of the comparative alloy.

As shown in FIGS. 8 and 9, the melting temperature ranges were significantly reduced as Si was added to the alloys of Examples 1 and 2, and the 3CoSiTi and 6CoSiTi alloys containing Si and Ti were 1287 ~, respectively. It was greatly reduced to 1341 ℃ and 1301 ~ 1351 ℃. It is about 100 ℃ higher than the comparative example (Rexillium3) alloy with the lowest melting temperature of commercial alloys, but it is similar to other comparative example (Tilite1234 alloy) or lower than the other comparative example (Vera Bond2 alloy). .

As shown in FIGS. 10 and 11, the corrosion current density at the corrosion potential of 250 kV was significantly lowered as Si was added. Furthermore, the 3CoSiTi alloy containing Si and Ti is -3.71A / cm 3, and the 6CoSiTi alloy is Although it rapidly decreased to -4.08 A / cm 3, the corrosion characteristics of Example 1 and Example 2 alloys were better than those of the comparative alloys.

The coefficient of thermal expansion was 14.7㎛ / m ℃ for the 3CoSiTi alloy with Si and Ti mixed together, and 14.8㎛ / m ℃ for the 6CoSiTi alloy. Values similar to those of 15.2 μm / m ° C. of the comparative example (Collonbium Type 1 alloy) different from those shown in ° C were shown.

As described above, the alloys designed according to the present invention, that is, 3CoSiTi alloy and 6CoSiTi alloy, have better corrosion characteristics than commercial alloys of comparative examples, hardness and thermal expansion coefficients have similar ranges, and melting temperature ranges have no practical problem, so that they can be used for dental casting. It was confirmed that the alloy can be used.

As such, the present invention is excellent in corrosion resistance and biological stability, good biocompatibility, mechanical and mechanical properties in the oral cavity without the use of Be, which includes allergic, toxic, or carcinogenic potential and various other problems in the oral environment. The mechanical properties are also very useful inventions that can provide the most suitable dental casting alloy with the living body.

Claims (1)

In the Ni-Cr-Mo-based dental casting alloy containing 64 to 70% by weight of Ni, 17 to 20% by weight of Cr, and 5.5 to 7.5% by weight of Mo, The dental casting alloy is 3 to 6% by weight of Co, 3 to 5% by weight of Ti, 1 to 3% by weight of Si for dental casting alloy, characterized in that it further comprises.

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