JPH0344138B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a golden-colored sintered material used for decorative members such as watch frames, tie pins, and necklaces. Traditionally used gold alloys (14K, 18K)
The hardness of the material is usually around Hv200, and even if it is hard, it is around Hv300 at most, so there is a problem in terms of wear resistance, and it has the disadvantage of being easily scratched when used as various decorative materials. It was hot. The present invention eliminates the drawbacks of the above gold alloy,
The objective is to provide a golden-colored sintered material with excellent wear resistance and corrosion resistance.
Contains 1 to 5 wt% of one or more of NbC in total amount, and 1 to 5 wt% of one or more of Ni and Co in total amount.
This is a sintered material for a decorative member, characterized in that it contains 1 to 5 wt% of Cu, and the balance is Au. The present invention will be explained in detail below with reference to Examples. TaC with an average particle size of 1.1 μm, TiC with an average particle size of 1.1 μm,
1.0μm WC,〃2.0μm NbC,〃2.8μm Ni,
A mixture of Co of 1.4 μm, Au of 10 μm, and Cu of 350 mesh in the proportions shown in Table 1 was mixed in a wet ball mill for 72 hours, and after drying, paraffin was added and 1.5 tan/ Press molding was performed in cm ² to obtain a molded product measuring 5.5 mm x 10 mm x 30 mm. Further, this molded product was pre-sintered at 800°C in a vacuum atmosphere to remove paraffin, and then sintered for 30 to 60 minutes at each temperature shown in Table 1 with a degree of vacuum of 5 x 10 ^-2 mmHg. Ta. After grinding this sintered product with a diamond grindstone,
The hardness was measured. Furthermore, after grinding with a diamond grindstone, lapping was performed to conduct a corrosion resistance test and color tone observation. In the corrosion resistance test, the degree of cloudiness of the lap surface was examined after 48 hours of immersion in the artificial sweat shown in Table 2. These results are shown in Table 1.

[Table] - was not measured or evaluated due to insufficient sintering or poor sintering.

[Table] Here, the appropriate values for the amounts of each component in the material of the present invention will be discussed in consideration of the above test results. In other words, since the material of the present invention has a golden color tone as an essential requirement, the Au content should be kept at a minimum.
The maximum amount of Au is equivalent to that of 18K, since it is practically useless (as a decorative member) if there is too much Au.
75w/o. After limiting the Au content in this way, if the TaC content is less than 10w/o, the hardness will be insufficient and there will be problems in terms of wear resistance, as seen in the example of sample No. 9, and sample No. As can be seen from the example in .10, sinterability is poor when the amount exceeds 77wt%. Therefore, the amount of TaC must be 10 to 76 wt%. By the way, TiC, WC, and NbC are all golden in color and cannot be added in large quantities, but their hardness is higher than TaC, so at least 1w/o is added to maintain the hardness of the sintered material. There is a need. This is because, as shown in sample No. 11, if the total content of one or more of TiC, WC, and NbC is less than 1 wt%, hardness is insufficient. Also, if the total content of one or more of TiC, WC, and NbC is more than 5w/o, the color tone will deviate from golden yellow, as shown in sample No.
o. Ni and Co are added to improve sinterability, but as can be seen from the comparison between sample No. 1 and sample No. 13, the total content of one or more of Ni and Co
If it is less than 1wt%, insufficient sintering will occur, so 1wt%
% or more is necessary, but if it exceeds 5 wt%, the hardness decreases as shown in sample No. 14, so it is necessary to set it to 1 to 5 wt%. In addition, Cu is added because it lowers the sintering temperature, increasing sinterability, and increases hardness through precipitation hardening of CuAu.
As you can see from the comparison, it is necessary to add 1wt% or more, but looking at sample No. 16, if it exceeds 5wt%, it will cause poor sintering (Cu will seep out), so it needs to be less than 5wt%. . As mentioned above, the material of the present invention has a golden color, is Au58.3w/o equivalent to 14K, has a hardness of Hv400 to 450, and has a small amount of Au.
The 20w/o type has a Hv of around 1000 and has excellent wear resistance. Furthermore, while conventional gold alloys were manufactured by melting, the material of the present invention is manufactured by powder metallurgy, which makes it possible to obtain materials with compositions that could not be manufactured using conventional methods, and whose size (especially It can be freely adjusted in terms of thickness (thinness) and has excellent corrosion resistance, making it ideal as a material for various decorative parts such as watch frames, lighters, tie pins, cufflinks, and nets.

Claims (1)

[Claims] 1 Contains 10 to 76 wt% TaC, and contains TiC, WC,
Contains 1 to 5 wt% of one or more of NbC in total amount, and 1 to 5 wt% of one or more of Ni and Co in total amount.
A sintered material for a decorative member, characterized in that the composition contains ~5wt% Cu, and 1~5wt% Cu, with the remainder being Au.