JP3946646B2 - Decorative gold alloy - Google Patents

Description

金、銅は、金属の中で特有な色をした金属であり、彩度（Ｃ^*値）が高い金属である。金属測色面を３０ｎｍレベルの鏡面に仕上げた場合、組織が均一であれば、金、銅レベル以上悪い標準偏差は示さない。３０ｎｍレベルの鏡面で測色することにより、金属の持つ色を再現性良く測色する事が出来ようになった。
【００２４】
今回採用した測色技術のレベルは、標準偏差の色差ΔＥ*ａｂで評価すると絶対値誤差は、平均で0.63、最大で1.34である。
色彩ハンドブックによれば、0.6〜1.1レベルは一級（厳格色差）で、各種誤差を考えた場合の実用的な許容差の限界と規定されている。従って、上記測定誤差は、実用色差として問題にならないレベルと考えることができる。
ここに開示した測色条件、測色環境をそろえる事により、誰でもいつでも金属の色を上記統計誤差の示す精度で安定して測色する事ができる。
【００２５】
【実施例】
次に、本発明の実施例、ならびに比較例を挙げ、本発明の特徴とするところを明らかにする。
【００２６】
（実施例１−１〜６、比較例１−１〜４）
本発明の第１の実施例であるＡｕ−Ｆｅ−Ｐｄ系の金合金を作製した後、測色ならびに硬さの定量化を行った。
実施例１−１〜６として具体的には、高周波溶解炉内に純度９９．９９％以上のＡｕ、Ｆｅ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｆｅが１．０質量％、２．５質量％、３．５質量％、５．０質量％、６．２５質量％、７．５質量％、でＰｄが１１．５質量％、１０．０質量％、９．０質量％、７．５質量％、６．２５質量％、５．０質量％、の６水準で、残部が不可避的不純物からなるように鋳込み、鋳造材を作製した。
また、比較例１−１〜４として、高周波溶解炉内に純度９９．９９％以上のＡｕ、Ｆｅ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｆｅが０．５質量％、８．５質量％、１０．０質量％、１２．５質量％、でＰｄが１２．０質量％、４．０質量％、２．５質量％、０．０質量％、の４水準で、残部が不可避的不純物からなるように鋳込み、鋳造材を作製した。
【００２７】
そして、上記鋳造材に対して、各々５０％の圧延加工を施し、最終焼鈍（７００℃×２０分保持して水冷）して、測色面径φ６ｍｍの試料を作成した。
次いで、各試料の試料表面粗さが３０ｎｍ程度になるまで鏡面仕上げを行った。
次いで、鏡面加工した試料表面の測色を行った。測色には、前述した通り、ミノルタ社製の分光測色計（CM-3600ｄ）を用い、Geometry（ジオメトリー）；拡散照明８°（ｄ/８°）受光（正反射光を含む）方式、測定条件；10°視野、D65光源を用いた。
また、鋳造ままの試料、５０％加工した試料に対して硬さ測定を行った。硬さ測定には、ビッカース硬度計を用い、試験荷重２００ｇ（１．９６Ｎ）、保持時間１５秒の条件で測定した。
【００２８】
以上により、表２に示す結果が得られた。
【表２】

ここで、Ｆｅの含有量が１．０質量％以上の場合、５０％加工した場合の硬さが、製品（リング）の実用的な硬さＨｖ１３０以上であった。
また、比較例１−４の結果に示す通り、Ｆｅの含有量が１０．０質量％を超えると、ダイヤカット時に生成されるＦｅ炭化物により製品のバイト寿命が短くなり生産性が低下した。
更に、Ｆｅの含有量が３．５〜７．５質量％の範囲では、５０％加工時の硬さがＨｖ１４０以上で且つダイヤカットによる生産性も良好であった。
【００２９】
（実施例２−１〜７、比較例２−３）
次いで、本発明の第２の実施例であるＡｕ−Ｍｎ−Ｐｄ系の金合金を作製した後、測色ならびに硬さの定量化を行った。
具体的には、真空置換不活性ガス雰囲気溶解炉内でに純度９９．９９％以上のＡｕ、Ｍｎ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｍｎが１．０質量％、１．５質量％、２．０質量％、２．５質量％、５．０質量％、６、２５質量％、７．５質量％で、Ｐｄが１１．５質量％、１１．０質量％、１０．５質量％、１０．０質量％、７．５質量％、６．２５質量％、５．０質量％、の７水準で、残部が不可避的不純物からなるように鋳込んだのち、上記第１の実施例と同様に、各々５０％の圧延加工を施し、最終焼鈍（７００℃×２０分保持して水冷）して、測色面径φ６ｍｍの試料を作成した。
また、比較例として、真空置換不活性ガス雰囲気溶解炉内に純度９９．９９％以上のＡｕ、Ｍｎ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｍｎが０．５質量％、８．０質量％、１０．０質量％で、Ｐｄが１２．０質量％、４．５質量％、２．５質量％、の４水準で、残部が不可避的不純物からなるように鋳込み、鋳造材を作製した。
【００３０】
次いで、上記と同様に、試料表面粗さが３０ｎｍ程度になるまで鏡面仕上げを行った後、鏡面加工した試料表面の測色を上記方法により行った。
また、上記と同様の条件で、試料の硬さを測定した。
以上により、表２に示す結果が得られた。
Ｍｎの含有量が、７．５質量％を超えると地金が硬くなり過ぎて加工性が悪くなった。
また、Ｍｎの含有量が１．５〜７．５質量％では、硬さがＨｖ１５０以上あり、且つ地金加工性が良好であった。
【００３１】
（実施例３−１〜５、比較例３−１）
次いで、本発明の第３の実施例であるＡｕ−Ｆｅ−Ｍｎ−Ｐｄ系の金合金を作製した後、測色ならびに硬さの定量化を行った。
具体的には、真空置換不活性ガス雰囲気溶解炉内に純度９９．９９％以上のＡｕ、Ｆｅ、Ｍｎ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｆｅが０．５質量％、１．５質量％、２．５質量％、３．５質量％、４．５質量％で、Ｍｎが４．５質量％、３．５質量％、２．５質量％、１．５質量％、０．５質量％、でＰｄが７．５質量％、の５水準で、残部が不可避的不純物からなるように鋳込んだのち、上記第１、２の実施例と同様に、各々５０％の圧延加工を施し、最終焼鈍（７００℃×２０分保持して水冷）して、測色面径φ６ｍｍの試料を作成した。
【００３２】
次いで、上記と同様に、試料表面粗さが３０ｎｍ程度になるまで鏡面仕上げを行った後、鏡面加工した試料表面の測色を上記方法により行った。
また、上記と同様の条件で、試料の硬さを測定した。
以上により、表２示す結果が得られた。
表２に示すとおり、硬度、ダイヤカット性、地金加工性、色の何れも良好であった。
【００３３】
次いで、本発明に対する比較例であるＡｕ−Ｆｅ−Ｍｎ−Ｐｄ系の金合金を作製した後、測色ならびに硬さの定量化を行った。
具体的には、真空置換不活性ガス雰囲気溶解炉内に純度９９．９９％以上のＡｕ、Ｆｅ、Ｍｎ、Ｐｄを入れて溶解し、Ａｕが８７．５質量％、Ｆｅが０．２５質量％で、Ｍｎが０．２５質量％で、Ｐｄが１２．０質量％、残部が不可避的不純物からなるように鋳込んだのち、上記第１の実施例と同様に、各々５０％の圧延加工を施し、最終焼鈍（７００℃×２０分保持して水冷）して、測色面径φ６ｍｍの試料を作成した。
【００３４】
次いで、上記と同様に、試料表面粗さが３０ｎｍ程度になるまで鏡面仕上げを行った後、鏡面加工した試料表面の測色を上記方法により行った。
また、上記と同様の条件で、試料の硬さを測定した。
以上により、表２に示す結果が得られた。
ここで、硬さがＨｖ１２０であるため、実用的な硬度を下回る結果となった。
【００３５】
（彩度の規定について）
現在、ホワイトゴールドとして市販されている金合金について上記した測色方法により彩度（Ｃ^*値）を測色した結果、彩度は４．９〜２２．５の範囲内であることが分かった。次いで、彩度が異なるいくつかのサンプルを用意し、その中から被験者がホワイトゴールドと思うものをピックアップさせる官能試験を行った。
具体的には、彩度が５．２〜１３．７までの間のいくつかのサンプルを被験者１５０人に見せて、ホワイトゴールドであると認定した人数を総人数で割った値を百分率で示した。
【００３６】
その結果を白色認定度数分布として図１に示す。
図１に示す白色認定度数分布は、横軸に彩度（Ｃ^*）、縦軸に頻度（％）を示した図であり、頻度累積正規分布に近似した曲線となる。一般に累積分布の５０％確率に相当する値をしきい値として扱うことから白色認定許容彩度として、統計学的には彩度が８．８以下であればよい。更に、彩度が８．４以下であれば、３人のうち２人はホワイトゴールドと認める結果となるため、更に望ましい。（目視官能試験結果）
【００３７】
評価基準
表３には、実施例と比較例で製作した金合金に関する特性を評価し、その結果が示されている。
【表３】

【００３８】
硬度評価については、リング硬度の測定の結果により
◎ ： 非常に良好（Ｈv１５０以上）
○ ： 良好(Ｈv１３０以上１５０未満)
× ： 不適当(Ｈv１３０未満)
として評価した。
【００３９】
ダイヤカット性については、リングを実際にダイヤカット加工した時に
◎ ： 切削面が鏡面に仕上り、切削抵抗がなく、バイト寿命が長い
× ： 切削面が鏡面にならない
として評価した。
【００４０】
地金加工性については、圧延加工及びリング加工時の加工性の結果により
◎ ： 延性が良好、リング加工性が良好
○ ： リング加工は出来るが、圧延性やリング加工性が若干悪い
× ： 圧延時に割れが発生、リング加工が出来ない
として評価した。
【００４１】
白色性については、彩度の測定結果により
◎ ： 良好(８．４以下のもの)
× ： 不適当
として評価した。
【００４２】
【発明の効果】
本発明によれば、２１Ｋの相当する金性の金合金において、ホワイトゴールドの色調を有し、同時に、鋳造状態或いは加工後の硬さが実用上問題のない、より高品位の金合金を提供することができる。加えて、Ｎｉを含まないので金属アレルギーの問題が発生することもない。
【図面の簡単な説明】
【図１】白色認定度数分布を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a decorative gold alloy used for a decorative tool such as a ring, a necklace, a brooch and a tie pin.
[0002]
[Prior art]
Conventionally, white gold (white gold alloy) based on gold (Au) has been developed and used as a substitute alloy of expensive platinum (Pt).
White gold is generally manufactured by adding nickel (Ni) or palladium (Pd) to gold of 20K (carat) or less (for example, Patent Document 1).
By the way, in order to make white gold with a higher quality, it is conceivable to increase the gold property (gold content).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-238333
[Problems to be solved by the invention]
However, the above-described nickel-based and palladium-based white gold has a problem in that whiteness (saturation) and mechanical properties (hardness) deteriorate as the gold property increases.
Moreover, since nickel is known to cause metal allergy, it is desirable to use white gold that does not contain nickel.
[0005]
The present invention has been made in view of the above circumstances, and has a higher-grade decorative gold alloy that has no problem of metal allergy, has a color tone of white gold, and has no practical problem of hardness. The issue is to provide.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventor first established a method for objectively quantifying the colorimetry of a metal color, and then, using the established colorimetry method, a gold added with various elements to gold. As a result of diligent research on the colorimetry and hardness of the alloy, we have developed a gold alloy for decoration that has a white gold color tone and no problem in terms of hardness and has a higher-class feel than conventional white gold. It was. In other words, the present invention has been established for the first time by establishing a colorimetric method for quantifying metal colorimetry, which has been difficult to quantify with low reproducibility in the past, with such a colorimetric method.
More specifically, the inventor uses at least one of Fe and Mn based on 21K (Au = 87.5% by mass), which is more metallic than 20K (Au = 83.3% by mass). By adding an appropriate amount, we have developed a higher-grade decorative gold alloy that has a white gold color tone and has no practical problem.
[0007]
That is, the invention described in claim 1 includes 87.2 to 87.8% by mass of Au, 1.0 to 7.5% by mass of Fe, and 5.0 to 11.5% by mass of Pd, and the balance Is made of other inevitable impurities.
[0008]
The invention according to claim 2 includes 87.2 to 87.8% by mass of Au, 1.0 to 7.5% by mass of Mn, 5.0 to 11.5% by mass of Pd, and the remainder being other It consists of inevitable impurities.
[0009]
According to the third aspect of the present invention, Au is 87.2 to 87.8 mass%, Fe is 1.0 to 6.5 mass%, Mn is 1.0 to 6.5 mass%, and Pd is 5.0. ˜10.5% by mass, the balance being composed of other inevitable impurities.
[0010]
The invention according to claim 4 is the decorative gold alloy according to any one of claims 1 to 3,
Based on the color measurement method of the reflective object, the saturation is 8.4 or less when color measurement is performed with light D65 illumination and a 10 ° field of view.
Here, the color measurement method of the reflecting object is a color measurement method based on a diffuse illumination 8 ° (d / 8 °) light reception (including regular reflection light) method compliant with JIS.
The saturation is a value evaluated by the saturation C ^* of the L ^* C ^* h color system.
[0011]
Hereinafter, the reasons for limiting each element of the decorative gold alloy will be described.
In the invention of claim 1, the gold content of 87.2-87.8% by mass is considered to be a gold property exceeding 20K (Au = 83.3% by mass). This is because a composition of 21K (Au = 87.5% by mass) that does not exist is used. Moreover, this range is because ± 0.3 mass% of the general test tolerance of the gold alloy is adopted.
When the metallicity is increased, the saturation and hardness deteriorate, so Fe was selected as an additive element for improving such characteristics. The reason for selecting Fe is that Fe can lower the saturation and increase the hardness beyond a practical level as compared with other additive elements such as Pd.
[0012]
The reason why the Fe content is 1.0% by mass or more is that if it is less than this, a practical product (ring) hardness of Hv 130 or more cannot be obtained.
Here, the reason why the lower limit of practical hardness is set to Hv130 is that the hardness of rings that are usually marketed is mostly Hv70-100 rings, so the lower limit of hardness as a design standard for rings is set internally. This is because Hv130 is set. If the hardness is less than Hv130, scratches and the like are likely to occur during use, causing problems in practical use.
The reason why the Fe content is 7.5% by mass or less is that when it exceeds 7.5% by mass, the problem that the tool life due to Fe carbides generated during diamond cutting deteriorates cannot be ignored.
The reason why Pd is selected as an additive element other than Fe is that the alloy is whitened and does not cause a metal allergy problem such as Ni.
Pd has an effect of decreasing the saturation as the addition amount increases, but the hardness decreases as the addition amount increases.
The reason why the content of Pd is set to 5.0% by mass or more is that if it is less than this, the diamond cutting property and the metal workability deteriorate.
Moreover, the content of Pd is set to 11.5% by mass or less. When the content exceeds 11.5% by mass, the hardness of the ring becomes less than Hv130, and there is a problem in practical use because scratches and the like are likely to occur during use. Because it happens.
[0013]
In the invention of claim 2, the gold content is 87.2 to 87.8% by mass for the same reason as in claim 1.
The reason why Mn is selected as an additive element is that Mn can lower the saturation and increase the hardness to a practical level or more as compared with an additive element such as Pd.
In addition, when Fe and Mn are compared, in the case of the same addition amount, Mn can raise the hardness more, but Fe is superior in component stability at the time of manufacture.
[0014]
The reason why the Mn content is 1.0% by mass or more is that the hardness is about Hv130 or more as in the case of claim 1, and Mn is a molten alloy when the vapor pressure is high and less than 1.0% by mass. This is because it is difficult to adjust the ingredients during conversion.
The reason why the Mn content is 7.5% by mass or less is that when it exceeds 7.5% by mass, the workability deteriorates.
The reason why Pd is selected as an adjustment element other than Fe is to make the alloy white and to prevent the problem of metal allergy like Ni.
Pd has an effect of decreasing the saturation as the addition amount increases, but the hardness decreases as the addition amount increases.
The reason why the Pd content is 5.0% by mass or more is that if it is less than this, the metal workability deteriorates.
Moreover, the content of Pd is set to 11.5% by mass or less. When the content exceeds 11.5% by mass, the hardness of the ring becomes less than Hv130, and there is a problem in practical use because scratches and the like are likely to occur during use. Because it happens.
[0015]
In the invention of claim 3, the gold content is 87.2 to 87.8% by mass for the same reason as in claim 1.
In addition, it is in this range that Fe is 1.0 to 6.5% by mass, Mn is 1.0 to 6.5% by mass, and Pd is 5.0 to 10.5% by mass. This is because Hv150 or higher and the metal workability and the diamond diamond cutting performance are also improved.
[0016]
In the invention according to claim 4, the reason that the saturation is more preferably 8.4 or less is based on the result of a visual sensory test described later. That is, as a result of measuring the saturation (C ^* ) of a gold alloy marketed as white gold by an established colorimetric method, it was found that there was a variation of 4.9 to 22.5. And the knowledge that there is a relation approximated to the cumulative normal distribution curve between the visual evaluation and the numerical value of saturation was obtained. In general, the value corresponding to the 50% probability of the cumulative distribution is handled as a threshold value, and therefore, as the white certified permissible saturation, statistically, the saturation may be 8.8 or less, and the saturation is 8. If it was 4 or less, 2 out of 3 results were recognized as white gold, so this range was limited.
[0017]
As described above, according to the present invention, there is no problem of metal allergy, a white gold color tone, and at the same time, a higher-grade gold alloy that has no practical problem in cast state or hardness after processing is provided. can do.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the L ^* a ^* b ^* color system and the L ^* C ^* h color system conforming to JIS Z 8729 are used for digitizing the color in this embodiment.
[0019]
[Color measurement method]
First, the color measurement method in the present invention will be described.
Generally, in order to feel the color, three elements of (1) vision, (2) light source, and (3) object are necessary.
{Circle around (1)} Visual sight has individual differences, and visual quantification is difficult. Therefore, a spectrocolorimeter is used as a device for replacing the visual part with a sensor and digitizing it.
Several color measurement methods have been proposed by JIS, and a color measurement method (illumination light receiving optical system: geometry) suitable for the sample can be selected.
[0020]
{Circle around (2)} The light source can be optimized by specifying the colorimetric conditions such as the light source itself, the optical path (angle, etc.), the visual field, and the treatment of specularly reflected light.
(1) and (2) depend on the spectrocolorimeter and can be solved by optimizing the measuring machine and the colorimetric conditions. Specifically, the color measurement method (Geometry), the absolute value accuracy of the colorimeter, the instrument error, etc. are important.
[0021]
Therefore, for this color measurement, a spectrocolorimeter (CM-3600d) manufactured by Minolta is used, Geometry; diffuse illumination 8 ° (d / 8 °) light reception (including regular reflection light), Measurement conditions: 10 ° field of view, D65 light source.
Absolute value accuracy is an inherent performance of the measuring instrument, and the absolute value accuracy published by the manufacturer of CM-3600d (Minolta) used this time is priced by NPL (National Physical Laboratory: UK). Further, the color difference ΔE * ab in the 22 colors of the color tiles is 0.33 on average and Max 0.94 (when regular reflection light is included). The machine difference is within △ E * ab 0.15.
Therefore, if there is no fluctuation in the measurement object and the measurement environment is constant, the absolute value accuracy of the CM-3600d can be considered to be ΔE * ab <0.48 on average and ΔE * ab <1.09 at maximum.
[0022]
{Circle around (3)} When the object is a metal, if the structure is uniform, it is considered that the spectral reflection characteristics are uniquely determined by the composition.
However, even if the colorimetric conditions are determined, the colorimetric results and visual appearance differ depending on the surface condition of the sample. It is important to make the surface condition the same for reproducibility.
In order to eliminate the influence of the viewing angle and the colorimetric angle, the rough surface roughened so that the surface is diffusely reflected has better visual stability than the mirror surface. However, when quantifying numerically, it is difficult to roughen the surface with good reproducibility. Therefore, surface roughness is eliminated as much as possible, and color measurement with high numerical reproducibility can be performed by performing color measurement with a highly accurate mirror surface and optimized color measurement conditions. The level of the measurement mirror surface was an average surface roughness of about 30 nm, and a stable result was obtained by measuring the color within 60 minutes after the generation of the new surface as much as possible.
[0023]
Table 1 shows the color measurement results obtained by the above color measurement method.
[Table 1]

Gold and copper are metals having a unique color among metals, and are high in saturation (C ^* value). When the metal color measurement surface is finished to a mirror surface of 30 nm level, if the structure is uniform, the standard deviation worse than the gold and copper levels is not shown. By measuring colors with a mirror surface of 30 nm level, it is now possible to measure colors with high reproducibility.
[0024]
The level of the colorimetric technique adopted this time is an absolute value error of 0.63 on average and 1.34 at maximum when evaluated by the color difference ΔE * ab of standard deviation.
According to the Color Handbook, levels 0.6 to 1.1 are first class (strict color difference), and are defined as practical tolerance limits when various errors are considered. Therefore, the measurement error can be considered as a level that does not cause a problem as a practical color difference.
By aligning the colorimetric conditions and colorimetric environment disclosed here, anyone can always measure the color of metal stably with the accuracy indicated by the statistical error.
[0025]
【Example】
Next, examples of the present invention and comparative examples will be given to clarify the features of the present invention.
[0026]
(Examples 1-1 to 6, Comparative Examples 1-1 to 4)
After producing an Au-Fe-Pd-based gold alloy according to the first embodiment of the present invention, colorimetry and hardness were quantified.
Specifically, as Examples 1-1 to 6, Au, Fe, and Pd having a purity of 99.99% or more were placed in a high-frequency melting furnace and melted, and Au was 87.5 mass% and Fe was 1.0 mass. %, 2.5 mass%, 3.5 mass%, 5.0 mass%, 6.25 mass%, 7.5 mass%, and Pd of 11.5 mass%, 10.0 mass%, 9.0 Casting materials were prepared by casting so that the balance was inevitable impurities at 6 levels of mass%, 7.5 mass%, 6.25 mass%, and 5.0 mass%.
Further, as Comparative Examples 1-1 to 4, Au, Fe, and Pd having a purity of 99.99% or more were placed in a high-frequency melting furnace and melted, and Au was 87.5 mass%, Fe was 0.5 mass%, 8.5 mass%, 10.0 mass%, 12.5 mass%, and Pd of 12.0 mass%, 4.0 mass%, 2.5 mass%, and 0.0 mass%. Casting was performed by casting so that the remainder was made of inevitable impurities.
[0027]
Each of the cast materials was subjected to a rolling process of 50%, and finally annealed (held at 700 ° C. for 20 minutes and cooled with water) to prepare a sample having a colorimetric surface diameter of 6 mm.
Next, mirror finishing was performed until the sample surface roughness of each sample was about 30 nm.
Next, color measurement was performed on the mirror-finished sample surface. As described above, for colorimetry, a spectrocolorimeter (CM-3600d) manufactured by Minolta is used, Geometry; diffuse illumination 8 ° (d / 8 °) light reception (including regular reflection light), Measurement conditions: 10 ° field of view, D65 light source was used.
In addition, hardness measurement was performed on an as-cast sample and a sample processed 50%. The hardness was measured using a Vickers hardness tester under the conditions of a test load of 200 g (1.96 N) and a holding time of 15 seconds.
[0028]
As a result, the results shown in Table 2 were obtained.
[Table 2]

Here, when the Fe content was 1.0% by mass or more, the hardness when processed by 50% was a practical hardness Hv130 or more of the product (ring).
In addition, as shown in the results of Comparative Example 1-4, when the Fe content exceeds 10.0% by mass, the bite life of the product is shortened due to Fe carbide generated at the time of diamond cutting, and the productivity is lowered.
Furthermore, when the Fe content was in the range of 3.5 to 7.5% by mass, the hardness at the time of 50% processing was Hv140 or more, and the productivity by diamond cutting was good.
[0029]
(Examples 2-1 to 7, Comparative Example 2-3)
Next, after producing an Au—Mn—Pd-based gold alloy according to the second embodiment of the present invention, colorimetry and hardness were quantified.
Specifically, in a vacuum substitution inert gas atmosphere melting furnace, Au, Mn, and Pd having a purity of 99.99% or more are placed and melted, Au is 87.5% by mass, Mn is 1.0% by mass, 1.5 mass%, 2.0 mass%, 2.5 mass%, 5.0 mass%, 6, 25 mass%, 7.5 mass%, Pd is 11.5 mass%, 11.0 mass% After casting at 7 levels of 10.5% by mass, 10.0% by mass, 7.5% by mass, 6.25% by mass, and 5.0% by mass, the remainder being inevitable impurities, In the same manner as in the first example, 50% rolling was performed, and final annealing (700 ° C. × 20 minutes holding and water cooling) was performed to prepare a sample having a colorimetric surface diameter of φ6 mm.
In addition, as a comparative example, Au, Mn, and Pd having a purity of 99.99% or more were placed in a vacuum substitution inert gas atmosphere melting furnace and dissolved, and Au was 87.5 mass%, Mn was 0.5 mass%, Casting is performed so that the balance is composed of unavoidable impurities at four levels of 8.0% by mass, 10.0% by mass, Pd by 12.0% by mass, 4.5% by mass, and 2.5% by mass. A material was prepared.
[0030]
Subsequently, in the same manner as described above, mirror finishing was performed until the sample surface roughness was about 30 nm, and then the color measurement of the mirror-finished sample surface was performed by the above method.
Further, the hardness of the sample was measured under the same conditions as described above.
As a result, the results shown in Table 2 were obtained.
When the Mn content exceeds 7.5% by mass, the base metal becomes too hard and the workability deteriorates.
Further, when the Mn content was 1.5 to 7.5% by mass, the hardness was Hv150 or more and the metal workability was good.
[0031]
(Examples 3-1 to 5 and Comparative example 3-1)
Next, after producing an Au—Fe—Mn—Pd-based gold alloy according to a third embodiment of the present invention, colorimetry and hardness were quantified.
Specifically, Au, Fe, Mn, and Pd having a purity of 99.99% or more are placed in a vacuum-displacement inert gas atmosphere melting furnace to dissolve, and Au is 87.5% by mass and Fe is 0.5% by mass. 1.5 mass%, 2.5 mass%, 3.5 mass%, 4.5 mass%, Mn is 4.5 mass%, 3.5 mass%, 2.5 mass%, 1.5 mass% %, 0.5% by mass and Pd of 7.5% by mass, and after casting so that the balance is made of inevitable impurities, 50% each was obtained as in the first and second embodiments. % Rolling was performed, and final annealing (700 ° C. × 20 minutes holding and water cooling) was performed to prepare a sample having a colorimetric surface diameter of φ6 mm.
[0032]
Subsequently, in the same manner as described above, mirror finishing was performed until the sample surface roughness was about 30 nm, and then the color measurement of the mirror-finished sample surface was performed by the above method.
Further, the hardness of the sample was measured under the same conditions as described above.
As a result, the results shown in Table 2 were obtained.
As shown in Table 2, all of hardness, diamond cutting property, metal workability, and color were good.
[0033]
Next, after preparing an Au—Fe—Mn—Pd-based gold alloy which is a comparative example for the present invention, colorimetry and hardness were quantified.
Specifically, Au, Fe, Mn, and Pd having a purity of 99.99% or more are placed in a vacuum-displacement inert gas atmosphere melting furnace and melted, and Au is 87.5% by mass and Fe is 0.25% by mass. Then, after casting so that Mn is 0.25% by mass, Pd is 12.0% by mass, and the balance is made of inevitable impurities, 50% of each is rolled in the same manner as in the first embodiment. The sample was subjected to final annealing (700 ° C. × 20 minutes and water-cooled) to prepare a sample having a colorimetric surface diameter of 6 mm.
[0034]
Subsequently, in the same manner as described above, mirror finishing was performed until the sample surface roughness was about 30 nm, and then the color measurement of the mirror-finished sample surface was performed by the above method.
Further, the hardness of the sample was measured under the same conditions as described above.
As a result, the results shown in Table 2 were obtained.
Here, since the hardness was Hv120, the result was less than the practical hardness.
[0035]
(About the regulation of saturation)
As a result of measuring the color saturation (C ^* value) of the gold alloy currently marketed as white gold by the color measurement method described above, it was found that the color saturation is in the range of 4.9 to 22.5. . Next, several samples with different saturations were prepared, and a sensory test was performed in which subjects picked up what they thought was white gold.
Specifically, some samples with saturation between 5.2 and 13.7 are shown to 150 subjects, and the number of people who are recognized as white gold divided by the total number is shown as a percentage. It was.
[0036]
The result is shown in FIG. 1 as a white certified power distribution.
The white certified frequency distribution shown in FIG. 1 is a diagram in which the horizontal axis represents saturation (C ^* ) and the vertical axis represents frequency (%), and is a curve that approximates a frequency cumulative normal distribution. Since a value corresponding to the 50% probability of the cumulative distribution is generally handled as a threshold value, it is sufficient that the saturation is 8.8 or less statistically as the white certified allowable saturation. Furthermore, if the saturation is 8.4 or less, two of the three people recognize white gold, which is more desirable. (Visual sensory test results)
[0037]
Evaluation criteria table 3 evaluates the characteristics of the gold alloys produced in the examples and comparative examples, and shows the results.
[Table 3]

[0038]
For hardness evaluation, ◎: very good (Hv 150 or higher) according to the results of ring hardness measurement
○: Good (Hv 130 or more and less than 150)
×: Inappropriate (less than Hv130)
As evaluated.
[0039]
The diamond cutting properties were evaluated when the ring was actually diamond cut. ◎: The cutting surface finished to a mirror surface, no cutting resistance, and a long tool life. ×: The cutting surface was evaluated not to be a mirror surface.
[0040]
Regarding the metal workability, ◎: Good ductility, good ring workability ○: Ring processing is possible, but rollability and ring workability are slightly poor ×: Rolling It was evaluated that cracking sometimes occurred and ring processing could not be performed.
[0041]
For whiteness, ◎: good (less than 8.4) according to the measurement result of saturation
X: Evaluated as inappropriate.
[0042]
【The invention's effect】
According to the present invention, a gold alloy equivalent to 21K has a white gold color tone, and at the same time, provides a higher-grade gold alloy that has no practical problem in cast state or hardness after processing. can do. In addition, since it does not contain Ni, the problem of metal allergy does not occur.
[Brief description of the drawings]
FIG. 1 is a diagram showing a white certified power distribution.

Claims (4)

Au is 87.2 to 87.8% by mass, Fe is 1.0 to 7.5% by mass, Pd is 5.0 to 11.5% by mass, and the balance is composed of other inevitable impurities. Decorative gold alloy. Au is 87.2 to 87.8% by mass, Mn is 1.0 to 7.5% by mass, Pd is 5.0 to 11.5% by mass, and the balance is composed of other inevitable impurities. Decorative gold alloy. Au is 87.2-87.8 mass%, Fe is 1.0-6.5 mass%, Mn is 1.0-6.5 mass%, Pd is 5.0-10.5 mass%, the balance Is a decorative gold alloy characterized by comprising other inevitable impurities. In the decorative gold alloy according to any one of claims 1 to 3,
A decorative gold alloy having a saturation of 8.4 or less when measured with a light D65 illumination and a 10 ° field of view, based on a color measurement method of a reflective object.

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