JP3267055B2 - Pure Au powder for producing pure gold clay with excellent sinterability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pure Au powder excellent in sinterability for mixing with pure gold clay.

[0002]

2. Description of the Related Art A plastic composition (hereinafter, referred to as pure gold clay) containing high-purity Au powder is molded into a predetermined shape, and is fired with this molded product to produce a molded product (hereinafter, referred to as a pure gold art craft, a decorative product, etc.) , A pure gold clay) is known, and the above pure gold clay is made of high-purity Au powder: 50 to 90% by weight, a cellulose-based water-soluble binder: 0.8 to 8% by weight, a surfactant: 0.03 to 3% by weight, fats and oils: 0.1 to
It is also known that the composition contains 3% by weight, with the balance being composed of water and unavoidable impurities (JP-A-4-267).
No. 07 gazette).

[0003]

However, it takes a long time for ordinary pure gold clay containing high-purity Au powder to bake,
The strength, elongation, hardness, etc. of the obtained pure gold molded article are insufficient, so that it is impossible to produce a pure gold molded article having a complicated and thin shape, and is added to pure gold clay to shorten the sintering time. Although refinement of the particle size of the high-purity Au powder has also been performed, if the particle size of the high-purity Au powder is excessively reduced, the sintering time is shortened, but the moldability of the pure gold clay is deteriorated. There were challenges.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
Research has been conducted to obtain a pure gold clay which can be fired in a shorter time even with Au powder having a normal particle size, and in which the strength of a solid gold molded product obtained by firing is excellent. As a result, as pure Au powder contained in pure gold clay, Ag:
Pure A containing 50-1000 ppm and having a purity of 99.9% or more
The use of u powder has improved the sintering property without making the particle size of the pure Au powder extremely small, and obtained a study result that a pure gold model having a predetermined strength can be obtained.

The present invention has been made on the basis of the above research results, and has a purity of 99.9% by weight or more and contains 50 to 1000 ppm of Ag. It has characteristics in powder.

The reason why the content of Ag is limited to 50 to 1000 ppm is that if the content is less than 50 ppm, the strength and elongation are not sufficient, so that it is impossible to cope with complicated shapes and thinner shapes.
If the content exceeds 000 ppm, the quality will deteriorate and pure Au
This is because not only can it not be regarded as powder, but also the elongation of the pure gold shaped article becomes small and the time required for complete baking becomes long. The more preferable range of the Ag content contained in the pure Au powder excellent in sinterability of the present invention is 100 to 500 ppm.

[0007]

EXAMPLE A hydrochloric acid solution having a different Ag concentration was added to an aqueous solution of chloroauric acid (HAuCl ₄ ), and after adjusting the pH, the mixture was reduced with an excess of potassium sulfite.
Pure Au powders 1 to 11 of the present invention, comparative pure Au powders 1 to 3, and a conventional pure Au powder containing 0 μm of the amount of Ag shown in Table 1 were obtained. After washing these pure Au powders,
Ethyl cellulose: 2.0% by weight, surfactant: 0.4% by weight, n-dibutyl phthalate: 0.7% by weight, balance: water based on 80% by weight of the pure Au powder. And kneaded to produce pure gold clay. Using this pure gold clay, rod-shaped molded articles having a length of 3 mm, a width of 3 mm, and a length of 100 mm were prepared, and these rod-shaped molded articles were charged into an electric furnace.
The sample was kept at 1000 ° C. for 2 hours to produce a pure gold sintered body sample. These pure gold sintered body samples were subjected to a tensile test, and their breaking strength and breaking elongation were measured. The measurement results are shown in Table 1.

[0008] Separately, the above-mentioned rod-shaped molded product is
The sintered body was sintered at 000 ° C., and the sintering time until the sintered body did not shrink any more (hereinafter referred to as a completely sintered state) was measured. The sex was evaluated.

[0009]

[Table 1]

[0010]

According to the results shown in Table 1, the pure Au of the present invention was obtained.
The pure gold sintered body sample manufactured using the pure gold clay including the powders 1 to 11 is superior in the breaking strength and the breaking elongation as compared with the conventional pure gold sintered body sample manufactured using the pure gold clay including the conventional pure Au powder. It can be seen that, even if the particle size of the powder is the same, the time required for the molded body made of pure gold clay containing the pure powders 1 to 11 of the present invention to be in a completely sintered state is short, and the sinterability is excellent.

However, it can also be seen that a gold sintered body sample prepared using a pure gold clay containing a comparatively pure Au powder 2-3 containing an Ag content exceeding 1000 ppm is not preferable because the elongation at break decreases.

As described above, the use of the pure Au powder of the present invention can provide a pure gold clay which is superior to the conventional one.

Claims (1)

(57) [Claims] Claims: 1. A material having a purity of 99.9% by weight or more,
Pure Au powder for producing pure gold clay excellent in sinterability, characterized by containing 50 to 1000 ppm.