JPH08311578A - Gold alloy for ornament - Google Patents

Abstract

PURPOSE: To provide a gold alloy for ornaments, improved in hardness and mechanical strength, hardly causing surface flaw, free from deformation, and excellent in color tone, by adding specific amounts of Si and Sm to Au and regulating the purity of Au to a specific high value. CONSTITUTION: Si and Sm are added to Au by 10-200ppm, respectively. If necessary, 10-1000ppm, in total, of one or more elements among Cu, Zn, Fe, Co, Ni, and Ga are further added and incorporated, and moreover, Au content is regulated to >=99.5wt.% even if other impurities are contained. By this method, the gold alloy for ornaments, improved in hardness as well as having excellent corrosion resistance and spreadability, inherent in gold, and an elegant gold color tone, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gold alloy for jewelry in which pure Au contains a trace amount of elements to increase hardness.

[0002]

2. Description of the Related Art Au is widely used for jewelry and the like because of its excellent corrosion resistance and spreadability, and its elegant color.

[0003]

However, since pure Au is extremely flexible and has low hardness and low mechanical strength, it has a problem that the surface is easily scratched and easily deformed.

[0004]

[Means for Solving the Problems] Therefore, the present invention provides Au to Si.
Is added as 10 to 200 ppm and Sm as 10 to 200 ppm as an additive element.Furthermore, in order to enhance the effect of adding an additive element to Cu, Zn, Fe, Co, Ni, Ga It contains 10 to 1000 ppm as one or more sub-additive elements.

The reason for using Si and Sm as additional elements is to improve the hardness after casting and after processing, and
Si and Sm produce compounds with relatively high melting points,
Prevents Sm from scattering. Cu, Zn, Fe, Co, N which are sub-additive elements
i and Ga have an effect on the fluidity at the time of casting, and improve the hardness by a synergistic effect with Si or Sm.

Addition amount of the additive elements Si and Sm is 10 to 200 ppm each
The reason is that if it is less than 10 ppm, it is not effective in improving hardness,
This is because if it exceeds 200 ppm, it becomes too hard and brittle. This is also because the above effect cannot be obtained if the amount of the sub-addition element added is less than 10 ppm.If the total amount of the sub-addition element and the impurity element exceeds 5000 ppm, the quality of gold deteriorates and the so-called pure color tone is also increased. This is because the golden color of Au is lost.

[0007]

According to the present invention described above, the hardness after casting is improved as compared with pure Au by the action of the additional element, and the hardness is increased by work hardening in the plastic working such as working of plate and wire. growing.

[0008]

EXAMPLES Examples of the present invention are shown in Table 1 below, together with pure Au as a conventional example.

[0009]

[Table 1]

For each sample shown in Table 1, first, an alloy containing Si and Sm, which are the additional elements shown in the examples, as main elements was cast by arc melting to form a master alloy. Next, pure Au was mixed with the master alloy with the composition shown in the example, and arc melting was performed in the same manner as above to form a cake-like cast body having a thickness of 10 mm, a width of 30 mm, and a length of 50 mm. It was formed into a wire and a plate by hot forging, and processed into a predetermined shape to obtain a sample.

As a result, as is apparent from the table, each example has a higher hardness than pure Au.

[0012]

According to the present invention described in detail above, Au
Even with a trace amount of additive element composition that can be called as, it has almost the same corrosion resistance as pure Au and the luster peculiar to pure Au, and has high hardness and mechanical strength, and when the addition amount is large, it is dramatically It has the effect of increasing the mechanical properties, and is a useful gold material not only for jewelry but also in a wide range of fields such as electronic parts and medical fields.

Claims (2)

[Claims] 1. Au in Au in an amount of 10 to 200 ppm and Sm in an amount of 10 to 200 p
99.5% by weight of Au component even after adding pm and including other impurities
The above is the gold alloy for jewelry, which is characterized by the above. 2. Au to 10 to 200 ppm and Sm to 10 to 200 p in Au
pm addition, and also contains one or more elements of Cu, Zn, Fe, Co, Ni, Ga in a total amount of 10 to 1000 ppm. Even if other impurities are included, the Au content should be 99.5% by weight or more. A characteristic gold alloy for jewelry.