JPH0678578B2 - High purity gold alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a high-purity gold alloy of 99.9% by weight or more, and particularly to a high-purity gold alloy having high toughness and excellent workability.

[Prior Art] Gold is used for various purposes because of its excellent decorative and chemical properties. However, high-grade gold generally has disadvantages such as softness, easy damage, and easy deformation, and lacks practical processing characteristics.

From this point of view, alloying, work hardening, heat treatment, etc. of the gold material have been carried out in order to obtain a gold material having hardness suitable for each purpose of use and excellent in processing characteristics.

However, high-grade 99.99% gold, etc. naturally has a limit in toughening by working or heat treatment, and is generally called carat gold, which is used as a ternary alloy of gold-silver-copper.

The carat gold is generally designed to have the above-mentioned gold-silver-copper alloy design on the premise of the color tone and hardness required according to the purpose of use.

However, in order to obtain a high-purity gold alloy that is a high-purity gold alloy and has high toughness and excellent processing characteristics, a special alloy design within a limited range is required, and at the same time,
Even for high-purity gold alloys having the same chemical composition, it was necessary to preset special casting conditions, processing conditions, and heat treatment conditions.

In general, the gold alloy obtained by using gold as a base material was not obtained by the precipitation hardening with a high-purity gold alloy of 99.9% by weight.

Therefore, referring to the binary alloy phase diagram (transformation diagram) of gold-nickel, gold-germanium, and gold-aluminum based on the theory of time hardening effect in general metal alloys, nickel is used as the extruded base material. Aluminum and aluminum were selected to attempt the extrusion hardening with a high-purity gold alloy.

Nickel as a base material for this deposition is Au in the temperature range below 800 ° C.
It was confirmed that + Ni was separated into two parts, and aluminum as a base material for extrusion was a solid solution in 3% by weight Au at 545 ° C., and it was observed that it extruded and hardened at a low temperature range.

However, in the binary alloy of gold-nickel and gold-aluminum using nickel and aluminum as the extruded base material, both nickel and aluminum need to be added in an amount of 1% by weight or more with respect to gold. On the other hand, when the addition amount of nickel and aluminum was less than 1% by weight, the desired hardening effect was not observed.

[Problems to be Solved by the Invention] However, with a high-purity gold alloy of 99.9% by weight or more,
Moreover, gold alloy materials having desired high toughness and excellent processing characteristics have been demanded from various fields.

In order to meet such demands, when a gold alloy material is used as a conductive contact material, it is necessary to have the characteristics that meet the requirements of the conductive characteristics and other characteristics, and when it is necessary to have the desired high toughness and workability, a necklace For various purposes, such as processing characteristics such as the above, decorative function and asset valuation at the same time, the provision thereof is required.

Therefore, we chose nickel and aluminum as the extruded base material based on the general theory of time hardening effect in metal alloys, and tried to obtain a high-purity gold alloy with high toughness. The hardening effect when used as a base material requires the addition amount of nickel and aluminum to be at least 1% by weight or more, and the addition of a smaller amount of the base material may enhance the sufficient hardness effect. could not.

From this point, molybdenum, vanadium, beryllium as the third element, with the intention of making the extruded base material more complete,
Iridium, yttrium, cobalt, zirconium,
Attempts were made to add titanium to the above-mentioned binary alloy of gold-nickel and gold-aluminum to enhance the hardness effect, but in each case, a high-purity gold alloy of 80 Hv (Vickers hardness) or higher was obtained. I couldn't.

The gold alloy according to the present invention has a high toughness commensurate with excellent processing characteristics in view of the inconvenience of the high purity and high hardness gold alloy in the past, and is a gold alloy having a high purity of 99.9% by weight or more. It is intended to be provided.

[Means for Solving the Problems] In order to achieve such an object, the present invention uses a high-purity gold base material having a gold content of 99.99% by weight, to which aluminum and ruthenium or germanium are added. Addition or addition of nickel and germanium or ruthenium to a high-purity gold base material with a quality of 99.99% and holding at a high temperature of 1400 ° C or higher, or melting and melting at about 1400 ° C and then repeatedly cooling and solidifying Do it.

By this treatment, 99.9% by weight of gold and 0.07-0.081% by weight of aluminum or 0.072-0.
A high-purity and high-hardness gold alloy consisting of 063% by weight and a trace amount of ruthenium or germanium is obtained.

[Example] Hereinafter, a typical example according to the present invention will be described in detail.

First, 99.9% gold by weight with 99.99% grade
Add 7 to 0.081% by weight and a trace amount of ruthenium or germanium.

Similarly, 99.99% gold with 99.99% gold grade and nickel
0.072 to 0.063% by weight and a trace amount of ruthenium or germanium are added.

0.07 to 0.081% by weight of this aluminum and a trace amount of ruthenium or germanium, or nickel 0.072 to 0.063
Addition in a range other than the addition of a small amount of germanium or ruthenium in the amount of wt%, especially when the addition amount is small, there was no sufficient protrusion effect and the desired hardness could not be obtained.
Further, when the amount of addition was increased, the effect of protrusion was satisfactory, but a 99.9% high-purity gold alloy could not be obtained.

As the alloy composition range, gold 99.9 wt%, aluminum 0.07 to 0.081 wt%, ruthenium 0.02 to 0.009 wt% composition range or gold 99.9 wt%, nickel 0.072 to 0.0
63% by weight, the composition range of germanium 0.018 to 0.027% by weight is preferable, the alloy with germanium added in place of ruthenium, even the alloy with ruthenium added in place of the germanium has enhanced time hardening effect ability and high hardness. I was able to obtain a gold alloy.

Further, a gold alloy having a composition of 99.9% by weight of gold, 0.081% by weight of aluminum and 0.009% by weight of ruthenium or a composition of 99.9% by weight of gold, 0.063% by weight of nickel and 0.027% by weight of germanium is more preferable and has a desired high toughness. It was possible to obtain a high-purity gold alloy with excellent workability.

Also, as an alternative to the ruthenium and germanium,
A high-purity gold alloy of 99.9% quality obtained by adding a trace amount of molybdenum, vanadium, beryllium, iridium, yttrium, cobalt, zirconium, and titanium to aluminum or nickel could not obtain a hardness of 80 Hv or more.

Then, the gold alloy material to which the element corresponding to the above chemical composition is added is melted in a vacuum or an atmosphere of argon gas, and 1400
Keep at high temperature above ℃.

Alternatively, the process of melting and cooling at about 1400 ° C. and then cooling and solidifying was repeated 2 to 3 times to carry out extrusion hardening in a high-purity gold alloy.

With the high-purity gold alloy that has undergone such melting treatment, a hardness of 70 Hv or higher was obtained in the cast state.

In addition, this cast ingot is simply rolled,
A hardness of 90H or higher was obtained at 50%.

The cast product obtained by a method other than the above casting conditions was extremely brittle and had poor workability and could not be used as a practical alloy.

One of the high-purity gold alloys thus obtained consists of 99.9% by weight of gold, 0.07 to 0.081% by weight of aluminum, and a trace amount of ruthenium or germanium. Other high-purity gold alloys are 99.9% by weight gold and 0.072-0.063% by weight nickel.
And a small amount of germanium or ruthenium.

When this gold alloy was subjected to heat treatment by holding it in the temperature range of 150 to 250 ° C. for 3 to 5 hours after the above-mentioned roll processing, a hardness of 140 Hv or more could be obtained.

Incidentally, ruthenium and germanium added in the above alloy design are aluminum which is solid-soluted in a high temperature range,
Enhance nickel deposition or compensate for separation. Further, the refinement of the alloy structure is promoted by the addition of ruthenium and germanium.

Example 1 Gold 99.9% by weight, Aluminum 0.081% by weight, Ruthenium
An alloy material having a compounding ratio of 0.009% by weight was held at a high temperature of 1400 ° C or higher and then returned to room temperature to obtain an alloy cast product.

In this dissolution treatment, the added aluminum was completely solid-dissolved in gold, but it extruded effectively in the temperature range of 545 ° C or lower.

It was confirmed that the aluminum deposition in this low temperature range was further enhanced in the state where ruthenium was added.

The alloy casting thus obtained was subjected to heat treatment.

This heat treatment was performed by holding the alloy cast product at 200 ° C. for 4 hours.

The hardness (Vickers hardness) of this alloy cast product was as follows. (Note that this hardness measurement was made by using a 10 mm diameter round bar-shaped alloy cast product as the main material, and measuring it with the surface layer and the center position of the main material. It is shown in comparison with the round bar of the cast product. Then, the alloy castings mentioned above are rolled, and the workability is 50%.
Processed into a flat plate shape, and the processed and cast product was used as the main material, and the hardness was measured with the surface layer and the center position of the main material, and was compared with a 99.99% -grade gold cast product under the same conditions. .

Example 2 The additive alloy species were nickel 0.063% by weight and germanium 0.027.
High-purity, high-hardness gold alloy was obtained under the same conditions as in Example 1 except that the weight% was changed.

It was confirmed that this gold alloy was hardened by melting treatment, especially separation of Au + Ni in the low temperature range. It was also confirmed that the added ruthenium is effective for supplementing the separation of Au + Ni and for making the composition finer.

The hardness of the obtained high-purity gold alloy was substantially the same as that in Example 1 above.

Example 3 A high-purity, high-hardness gold alloy was obtained under the same conditions as in Example 1 except that the melting treatment was repeated after melting at 140 ° C. and then cooling.

It was found that the hardness of the gold alloy obtained here was slightly better than that of the gold alloy obtained in Example 1.

Example 4 The additive alloy species were 0.07% by weight of aluminum and 0.9% of germanium.
High-purity, high-hardness gold alloy was obtained under the same conditions as in Example 1 except that the content was 03% by weight.

The hardness of the gold alloy obtained here was slightly inferior to that of the gold alloy obtained in Example 1, but there was no problem in processing.

Example 5 High purity with the same conditions as in Example 1 except that the additive alloy species were 0.072 wt% nickel and 0.02 wt% ruthenium,
A high hardness gold alloy was obtained.

The gold alloy obtained here was inferior in hardness to the gold alloy obtained in Example 1 and was found to have some difficulty in processing, and could be put to practical use.

Comparative Example 1 Only ruthenium was used as the additive alloy species and only nickel was used.
A gold alloy was obtained under the same conditions as in Example 1 except that 1% by weight was added.

The gold alloy obtained here was soft and easily scratched, had a hardness close to that of a 99.99% grade gold cast product, and was not suitable for processing.

Comparative Example 2 A gold alloy was obtained under the same conditions as in Example 2 except that nickel was used as the additive alloy species and 0.09 wt% was added without using germanium.

The gold alloy obtained here did not have a hardness suitable for processing as in Comparative Example 1.

Comparative Example 3 A gold alloy was obtained under the same conditions as in Example 1 except that the amount of aluminum added was 0.06% by weight.

The gold alloy obtained here did not have a hardness suitable for processing as in Comparative Example 1.

Comparative Example 4 A gold alloy was obtained under the same conditions as in Example 2 except that the amount of nickel added was 0.05% by weight.

The gold alloy obtained here did not have a hardness suitable for processing as in Comparative Example 1.

[Effect] The high-purity gold alloy according to the present invention has a high content of 99.9% by weight, and its hardness is increased. As a result, the processing characteristics of the high-purity gold alloy can be improved. .

In particular, by using a high-purity gold alloy, the mechanical strength of the gold material can be increased without impairing the electrical, chemical, or thermal characteristics of the gold material, and as a result, the constituent material of various electronic devices, etc. I was able to

Also, as a high-purity gold alloy, it is used as ornaments such as necklaces made of pure gold, pure gold crafts, and decorative clips that are not deformed or scratched due to its high toughness while maintaining its quality. I was able to.

Further, since it is a high-purity gold alloy having high quality, excellent corrosion resistance, and moderate hardness, it can be used as an important official seal or private seal.

Claims (1)

[Claims] 1. A gold base material to which a trace amount of aluminum or nickel and a trace amount of ruthenium or germanium are added,
This is maintained at a high temperature of 1400 ° C or higher or repeatedly melted at about 1400 ° C to be cooled and solidified to have a composition of 99.9% by weight of gold and 0.07 to 0.081% by weight of aluminum or 0.072 to 0.02% of nickel.
A high-purity gold alloy with high toughness, with 063% by weight and the balance being ruthenium or germanium.