JPH08311581A - 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 P and Si to Au and regulating the purity of Au to a specific high value. CONSTITUTION: P and Si are added by 5-1000ppm and 10-200ppm, respectively, to Au and 10-1000ppm, in total, of one or more elements among Sb, Cu, Zn, Fe, Co, Ni, Ga, Ag, and Ge are further added as auxiliary additive elements, if necessary. Moreover, the content of Au 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
Of 5 to 1000 ppm and Si as 10 to 200 ppm as an additive element, and further, in order to enhance the effect of adding the additive element to this, Sb, Cu, Zn, Fe, Co, Ni, Ga, It contains 10 to 1000 ppm of one or more of Ag and Ge as a secondary additive element.

The reason why P and Si are added elements is to improve the hardness after casting and after processing. The sub-additive elements Sb, Cu, Zn, Fe, Co, Ni, Ga, Ag and Ge have an effect on the fluidity during casting, and also have the effect of refining the crystal to improve the hardness. The additive amount of additive element is 5 to 1000ppm of P
Is set to 10 to 200 ppm because if P is less than 5 ppm and Si is less than 10 ppm, it is not effective in improving hardness, and if it exceeds P 1000 ppm and Si is more than 200 ppm, it becomes too hard and brittle.

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 is deteriorated and the color tone is deteriorated. This is because the so-called pure Au loses its golden color.

[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 P and Si, 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 contained 5 to 1000 ppm of P and 10 to 20 of Si in Au.
A gold alloy for jewelry, which contains 0ppm and contains 99.5% by weight or more of Au even if it contains other impurities. 2. Au in P is 5 to 1000 ppm and Si is 10 to 20 in Au.
0ppm added, Sb, Cu, Zn, Fe, Co, Ni, Ga, Ag, Ge one or more elements in total, 10-1000ppm added,
A gold alloy for jewelry, which contains 99.5% by weight or more of Au even if it contains other impurities.