JPS622031B2 - - Google Patents

Description

[Detailed description of the invention]

This invention has a surface hardening layer that has extremely high surface hardness, and therefore exhibits excellent abrasion resistance and scratch resistance in practical use, and is capable of obtaining various color tones. This relates to Au alloy members. In general, pure gold is extremely soft and has low strength, so it is made by adding ingredients such as Ag and Cu to give it a suitable strength, so-called 18K and 14K.
There are Au alloys such as However, when these Au alloys are used to manufacture decorative parts such as rings and necklaces, they are easily scratched because they do not yet have sufficient hardness, and it is difficult to create clear patterns on the decorative parts using the diamond cutting method. Even if these Au alloys are used, the edges will be severely worn and the pattern will become unclear.
When used in the manufacture of industrial parts such as contacts, bearings, or current collecting members, they have a relatively short service life due to their lack of hardness. moreover,
In addition, the color tones range from golden yellow to white to red, and there is a lack of variety in color tones, making it difficult to enjoy color tone changes. Therefore, from the above-mentioned viewpoint, the present inventors conducted research to develop an Au alloy member with particularly excellent wear resistance and scratch resistance, regardless of color tone. (all indicate weight%), one or more of Y and rare earth elements: 0.3 to 15%, one or two of Zr and Al: 0.1 to 5
%, and if necessary, (A) one or more of Ni, Co, Cr, Fe, Mn, and V: 0.1 to 20%, (B) Cu, Ag, and Contains one or more of Pd: 1 to 30%, one or two of the above (A) to (B),
The remainder consists of Au and unavoidable impurities.
When the surface of an Au alloy member is subjected to boriding treatment, the B diffused in from the surface and the Y contained as an alloy component.
A hardened surface layer consisting mainly of borides and rare earth elements is formed, and this hardened surface layer has a hardness of more than 500 on the Vickers hardness scale, and its color varies depending on the type of boride. Since it exhibits purple-red, bluish-purple, and blue colors, it has been found that in practical use, it exhibits excellent abrasion resistance and scratch resistance, and that it comes in a variety of color tones. This invention has been made based on the above findings, and the reason why the composition of the Au alloy member is limited as described above will be explained below. (a) Y and rare earth elements These components form a solid solution in the base material, but during boration treatment, they combine with B diffused from the surface,
It forms a surface hardening layer mainly composed of boride, which gives the Au alloy member excellent wear resistance and scratch resistance, and also has the effect of imparting a change in color tone depending on the type of boride. If the content is less than 0.3%, the desired effect cannot be obtained, while if the content exceeds 15%,
Since a large amount of intermetallic compounds with Au are formed and the Au alloy member itself becomes brittle, its content is set at 0.3 to 15%. (b) Zr and Al In addition to having a deoxidizing effect, these components have the effect of making borides finer and improving the adhesion of the hardened surface layer to the substrate, but if their content is less than 0.1%, The desired effect cannot be obtained in the above action, and on the other hand, if the content exceeds 5%, the workability of the member will deteriorate, so the content was set at 0.1 to 5%. Note that these are collectively referred to as adhesion improving components. (c) Ni, Co, Cr, Fe, Mn, and V All of these components form a solid solution in the base material and strengthen it as a solid solution. Since it has the effect of further improving the hardness of the hardened layer, it is selectively included when it is necessary to further improve the strength of the member and the hardness of the surface hardened layer, but its content is less than 0.1%. However, if the content exceeds 20%, the color tone imparted by the boride of Y and rare earth elements will be impaired and the color will become silvery white. The amount was determined to be 0.1-20%. Note that these components are collectively referred to as strength/surface hardness improving components. (d) Cu, Ag, and Pd These components have the effect of solid solution strengthening in the base material, so they can be used selectively when further improvement in the strength of the component is required. However, if the content is less than 1%, the desired strength improvement effect cannot be obtained, while if the content exceeds 30%, corrosion resistance will deteriorate, so the content should be reduced from 1 to 30%. It was determined that In addition,
These are collectively called strength-enhancing components. Incidentally, when melting the Au alloy member of the present invention, Cd, Zn, etc. may be used as a deoxidizing agent, but if each is contained in an amount of 3% or less, the properties of the member will not be impaired in any way. Next, the surface-hardened Au alloy member of the present invention will be specifically explained using examples. Example Using a TIG arc, necessary alloying metals and electrolytic Au were mixed and melted in a water-cooled copper crucible to prepare 10 g each of molten Au alloys having the compositions shown in Table 1. After that, it is cast into a mold to make a button-shaped slab, and then the surface of this slab is polished to make a chip material with dimensions of diameter: 10 mmφ x thickness: 1 mm, and this chip material is placed in a graphite crucible in advance. Molten flux ( _B4C : ₈₀ %, _H3PO3 : ₁₀ %, _{Na2B4O7 :}
The surface-hardened Au alloy chips 1 to 22 of the present invention were manufactured by subjecting the chips to a boronizing treatment by immersing them in a solution containing 10% (having a composition of 10%) for 24 hours, and then taking them out into the atmosphere. In addition, for the purpose of comparison, the component composition is shown in Table 1.

【table】

[Table] Conventional Ag alloy chip materials 1 to 3 were manufactured under the same conditions except that no boriding treatment was performed. After washing with hot water and buffing, the surface hardness of the surface hardened Au alloy chips 1 to 22 of the present invention and conventional Au alloy chips 1 to 3 obtained as a result is measured using a micro-Vickers meter (load: 100 g). At the same time, in order to observe the surface color tone and further evaluate the corrosion resistance, a 100-hour artificial sweat test was conducted to observe the presence or absence of discoloration. These results are the first
Shown in the table. Table 1 also shows surface hardening according to the present invention.
The Vickers hardness of Au alloy chips 1 to 22 before boriding treatment is also shown. From the results shown in Table 1, it can be seen that the surface hardening of the present invention
All of Au alloy chip materials 1 to 22 have significantly improved surface hardness through boriding treatment.
In addition to having a significantly high surface hardness of over 500 on the Vickers hardness (Hv), it also exhibits excellent corrosion resistance and a beautiful color tone, while it does not contain Y or rare earth elements as alloying components. It is clear that the conventional Au alloy chip materials 1 to 3, which were not subjected to the boriding treatment, had low surface hardness and low corrosion resistance, and had only an inferior decorative color tone. As mentioned above, the surface-hardened Au alloy member of the present invention has high hardness, so when used as decorative parts or industrial parts, it exhibits excellent wear resistance and scratch resistance, and also has a good color tone. In addition to being rich in
Since it has excellent corrosion resistance, it has industrially useful properties such as great decorative value.

Claims (1)

[Claims] 1 One or more of Y and rare earth elements: 0.3 to 15%, One or two of Zr and Al: 0.1 to 5
%, with the remainder consisting of Au and unavoidable impurities (weight %). 2 One or more of Y and rare earth elements: 0.3 to 15%, One or two of Zr and Al: 0.1 to 5
%, and further contains one of Ni, Co, Cr, Fe, Mn, and V
A surface hardened layer formed by boriding on the surface of an Au alloy member having a composition (by weight %) containing one or more species: 0.1 to 20%, and the remainder consisting of Au and unavoidable impurities. A surface-hardened Au alloy member. 3 One or more of Y and rare earth elements: 0.3 to 15%, One or two of Zr and Al: 0.1 to 5
%, and further contains one or more of Cu, Ag, and Pd: 1 to 30%, and the remainder is Au and unavoidable impurities (weight %). A surface hardened Au alloy member having a surface hardened layer formed by boriding treatment on the surface of the alloy member. 4 One or more of Y and rare earth elements: 0.3 to 15%, One or two of Zr and Al: 0.1 to 5
%, and further contains one of Ni, Co, Cr, Fe, Mn, and V.
A composition containing one or more species: 0.1 to 20%, one or more of Cu, Ag, and Pd: 1 to 30%, and the remainder consisting of Au and unavoidable impurities (wt%) A surface hardened Au alloy member comprising a surface hardened layer formed by boriding on the surface of the Au alloy member.