JPS616220A - Silver material for accessory - Google Patents

Abstract

PURPOSE:To obtain a lustrous accessory having improved hardness and taking hardly scratches by dispersing uniformly and finely a prescribed percentage of tin oxide in silver so as to prevent the coarsening of the grains during heat treatment. CONSTITUTION:A mixture of silver powder with tin oxide powder is subjected to powder metallurgical processing to obtain a silver material for an accessory contg. 1-15wt% tin oxide dispersed uniformly and finely in silver. The grains of the silver material are not coarsened by heat treatment such as annealing or brazing, and a lustrous accessory having improved hardness and hardly scratched is obtd.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to rings, necklaces, brooches, tie pins, cufflinks, and watch bands with one hour hand frame.

This invention relates to the improvement of silver materials used in decorative items such as lighters, writing implements, eyeglass frames, and earrings.

(Prior Art and Problems) Conventionally, silver has been used as a material for decorative items such as those mentioned above.
Copper (5-15% by weight) alloys are frequently used.

However, this silver-U4 (5 to 15% by weight) alloy tends to coarsen the crystal grains of the alloy during heat treatments such as annealing and brazing that are repeated several times during the manufacturing stage of decorative items, resulting in poor surface finish. If the silver-copper alloy is too shiny, it will become too soft and easily scratched. Since the copper inside is easily oxidized, a copper oxide film is formed on the surface of the material through heat treatment.This oxide film is strong and must be removed mechanically or by chemical treatment such as pickling. Also, since the oxide film is difficult to spread uniformly, it ultimately causes uneven coloring of the product.Furthermore, during brazing work, the brazing part oxidizes and the copper oxide makes it difficult to braze. There were problems such as the brazing being easily defective.

(Object of the Invention) The present invention was made to solve the problems of the above-mentioned silver material for decorative items made of a silver-copper alloy. The object of the present invention is to provide a silver material for decorative items that does not cause corrosion, has high hardness, does not form an oxide film, and does not cause defects during brazing.

(Means for Solving the Problems) The silver material for ornaments of the present invention has oxidized 4111-15 in silver.
% by weight is uniformly and finely dispersed.

In the silver material for ornaments of the present invention, 1 to 1 tin oxide is contained in silver.
The reason for dispersing 5% by weight7 is that if it is less than 1% by weight, coarsening of crystal grains during heat treatment such as annealing or brazing cannot be suppressed, and the hardness is low. This is because, although the effects of crystal grain refinement and hardness are improved, it becomes difficult to plastically work, causing the material to crack and become difficult to mold.

(Function) In the silver material for ornaments of the present invention having the above structure, the tin oxide uniformly and finely dispersed in the silver acts as a crystal grain refining agent during heat treatments such as annealing and brazing. Since it prevents crystal grains from becoming coarse due to heat treatment and maintains hardness higher than that of silver-copper alloys, it is easy to give a glossy finish in the final finish and is resistant to scratches. Also, since the tin oxide is already dispersed in the silver, annealing and
Since an oxide film is not formed during heat treatment in the atmosphere such as brazing, there is no need to remove the oxide film as is the case with silver-copper alloys, and color unevenness of the product does not occur.

Furthermore, since brazing parts do not oxidize, brazing is easy to work with, and brazing is less likely to cause defects.

(Examples and Conventional Examples) Examples 1 to 3 of the silver materials for ornaments of the present invention were produced by powder metallurgy and had the component compositions shown in the left column of the table below, and had the same composition as these silver materials for ornaments. Brooches were manufactured using silver materials for decorative items of Conventional Examples 1 to 3 having the component compositions shown in the left column of the table below. At this time, annealing was performed 3 times, brazing was performed once, and heat treatment was performed 4 times.

The finished surface of the broach produced in this manner was inspected, and the brazing strength and hardness were measured, and the results shown in the right column of the table below were obtained.

As is clear from the table above, the brooches made with the decorative silver materials of Examples 1 to 3 have a glossier finished surface compared to the brooches made with the decorative silver materials of Conventional Examples 1 to 3. It can be seen that there is no color unevenness, and that the brazing is strong and hard, making it difficult to scratch.

(Effects of the Invention) As can be seen from the above explanation, the silver material for ornaments of the present invention can prevent coarsening of crystal grains during heat treatments such as annealing and brazing, and can increase hardness. This makes it possible to produce shiny, scratch-resistant decorative items. In addition, the material for decorative items of the present invention does not form an oxide film during heat treatment such as annealing or brazing, so there is no need to remove the oxide film, and it is possible to manufacture decorative items without uneven color. can. Furthermore, since the silver material for ornaments of the present invention does not oxidize during brazing, the brazing process is easy, the brazing process is free from defects, and the brazing process allows the manufacture of highly strong decorative items. It has excellent effects such as being able to.

Claims (1)

[Claims] A silver material for ornaments comprising 1 to 15% by weight of tin oxide uniformly and finely dispersed in silver.