JP3652640B2 - Dental casting alloy - Google Patents

Description

【０００８】
＊ ：３７℃、０．９％塩化ナトリウム水溶液で７日間浸漬試験後の全金属イオン溶出量のＩＣＰ質量分析法による分析結果を示す。
＊＊ ：８４％Ｎｉのニッケル・クロム合金の評価結果を示す。
＊＊＊：◎非常に良い、○良い、□中程度、△劣る、×非常に劣る。
【０００９】
上記表１の結果から明らかなとおり、波動分析による評価結果との間にはニッケル・クロム合金を除き相関関係が見られた。特にＮｏ．１〜４の貴金属合金は腐食電位からの金属溶出量も少なく、波動分析による評価も一段と高くなっている。
【００１０】
【発明が解決しようとする課題】
本発明は、上記従来技術に鑑み、Ｐｄの量を減らしたホワイトゴールド系の類似系の改良を試み、Ｐｄの使用量を少なくすると共に、波動分析による評価も、表１におけるＮｏ．１、２とＮｏ．３、４との間位にある高い評価の合金であって、鋳巣や合金組成偏析のない耐変色性の歯科鋳造用合金を提供せんとするものである。
【００１１】
【課題を解決するための手段】
本発明は、重量％基準で、Ａｕ：３９．０〜４１．０％、Ｐｄ：４．０〜６．０％、Ｃｕ：１４．０〜１７．０％、Ａｇ：２９．０〜３１．０％、Ｉｎ：６．０〜８．０％、Ｉｒ：０．０３〜０．０５％、Ｚｎ：１．０〜３．０％、その他不可避不純物よりなることを特徴とする歯科鋳造用合金である。
【００１２】
すなわち、Ｐｄの量を４．０〜６．０％まで減らし、Ａｕの３９．０〜４１．０％までの増量とＩｎ添加とでＡｇの硫化による変色を抑える。しかも融点は９００℃以下になるから、鋳造性は良好となり、懸念された鋳巣の生成、合金組成偏析などは見られない。Ａｕ、Ｐｄ、Ａｇの量のいずれかが上記範囲を超えるとバランスがくずれて所期の効果を得られなくなる。
【００１３】
Ｉｎの量が本発明の範囲を超えると、機械的性質を妨げ、金属間化合物をつくってもろくする。７％程度で耐変色性および耐食性が増す。Ｚｎは脱酸剤として鋳造性を良くし、又、機械的性質を向上させる作用がある。さらにＺｎは耐変色性を向上する。そして、１．０〜３．０％の範囲が好適である。
【００１４】
ＡｇにＰｄが加わることによって結晶粒が微細化するが、微細化の進行はＰｄの量が４．０〜６．０％の範囲では緩慢になる。その際、微量（０．０３〜０．０５％）のＩｒの添加が微細化効果をさらに高める。
【００１５】
そして、本発明合金を波動分析にかけてみたところ、表１におけるＮｏ．２とＮｏ．３との間位の評価が得られ、生体に対する影響はないことも判った。
【００１６】
【発明の実施の形態】
本発明の実施例を比較例と共に説明する。
下記表２に示す組成の実施例合金および比較例合金を作製した。その融解温度も併記する。
【００１７】
【表２】

【００１８】
本発明の実施例合金は比較例合金に比べて融解温度が低い。これは鋳造性の良好なことを示している。
【００１９】
次に両者のビッカースかたさについて試験をした。かたさは鋳造のままと、軟化処理後、硬化処理後の３段階でしらべた。
【００２０】
軟化処理は実施例合金の場合は７００℃×１０分で水中急冷し、比較例合金の場合は、８００℃×１０分で水中急冷した。
【００２１】
硬化処理は、実施例合金の場合は３５０℃×１５分で徐冷し、比較例合金の場合は３５０℃×２０分で徐冷した。
結果を表３に示す。
【００２２】
【表３】

【００２３】
硬化熱処理した実施例合金を、硝酸５ｍｌ＋塩酸５０ｍｌの溶液で２０分腐食し、表面の金属組織写真をとった。これを図１に示す。図１の（イ）は１００倍、同（ロ）は４００倍の写真である。これらの写真から見られるように、実施例合金は固溶体組織であり、硬化処理したものは時効によって粒界からＡｕＣｕ規則格子が析出していることが明瞭に現れている。これによって強度が増し、伸びが減少し、機械的性質の向上が明瞭となる。
表４に本発明合金の機械的性質を比較例合金と対比して示す。
【００２４】
【表４】

【００２５】
上記本発明合金の耐力試験を直径１．９２ｍｍの合金棒を用いて行った試験データを図２、図３に示す。図２は軟化処理後の耐力の試験データであり、図３は硬化処理後の試験データである。
【００２６】
次に変色試験を分光分析計（ミノルタ製）を用いて行った。変色の状態は外観観察と標準色票の明度と彩度を示した。試験片を３７℃、０．１％硫化ナトリウム水溶液中に７日間全浸漬した。
結果を表５に示す。
【００２７】
【表５】

【００２８】
この表５から明らかなように、本発明合金の変色後の色相の変化は従来の金パラ合金に匹敵するものであった。
【００２９】
【発明の効果】
本発明は、Ｐｄの使用量を少なくしたのでコスト削減に効果があり、その上金属溶出量は少なく、波動分析の評価も高く、生体に対する影響はないものである。さらに融解温度が低いため鋳造性が良く、しかも、組織写真から見られるように鋳巣や合金組成偏析のない、変色後の色相の変化もない歯科鋳造用合金として優れた特性を有する。
【図面の簡単な説明】
【図１】本発明合金の硬化熱処理の表面金属組織を示す（イ）倍率１００の写真、結晶粒が微細化されている同（ロ）は倍率４００の写真である。
【図２】７００℃で軟化処理した本発明合金棒の応力と伸びの関係を示すグラフである。
【図３】図２と同じく３５０℃の硬化処理した本発明合金棒の応力と伸びの関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to improvements in dental casting alloys.
[0002]
[Prior art]
As dental casting alloys, 12% gold, silver, and palladium alloys (also known as gold and para alloys) for normal insurance have been established. However, in recent years, the price of palladium has risen, and the components have been adjusted in terms of economic burden. Reducing the content to 20% or less or reducing the palladium content to 0% has come to attract technical attention.
[0003]
However, such an alloy has a high melting point, requires heat treatment, and there has been a concern of casting holes and segregation of the alloy structure.
[0004]
In addition, the present inventors have previously applied wave analysis to dentistry, that is, studied the influence of metallic materials on living bodies based on wave analysis and published as papers. (DE, No. 125 Spring, published 25 April 1998, see pages 31-34)
[0005]
With wave analysis, in recent years, it has been elucidated that the vitality generated by living bodies is weak magnetism, and since this has a close relationship with waves, analytical instruments have been developed that take this as a wave of matter and measure it. Yes. A magnetic wave resonance analyzer is one example. Wave analysis of dental metal materials was performed using this analyzer. As a result, gold, platinum, zinc, noble metal alloys and the like had the highest measured values, and the influence on the living body was also good. At the same time, the influence of dental metal materials on the living body was investigated.
[0006]
Table 1 shows the relationship between the measurement results and metal corrosion. (Relationship between corrosion potential of various dental alloys and metal elution amount in 0.9% sodium chloride aqueous solution at 37 ° C)
[0007]
[Table 1]

[0008]
*: The analysis result by ICP mass spectrometry of the total metal ion elution amount after a 7-day immersion test in a 0.9% sodium chloride aqueous solution at 37 ° C. is shown.
**: Indicates the evaluation result of a nickel-chromium alloy of 84% Ni.
***: ◎ Very good, ○ Good, □ Medium, △ Inferior, × Very inferior.
[0009]
As is clear from the results in Table 1 above, there was a correlation with the evaluation results by wave analysis except for the nickel-chromium alloy. In particular, no. The precious metal alloys 1 to 4 have a small amount of metal elution from the corrosion potential, and the evaluation by wave analysis is much higher.
[0010]
[Problems to be solved by the invention]
In view of the above prior art, the present invention attempts to improve a white gold-based similar system in which the amount of Pd is reduced, and the amount of Pd used is reduced. 1, 2 and no. It is a highly evaluated alloy that is between 3 and 4, and is intended to provide a discoloration-resistant dental casting alloy that does not have castholes or alloy composition segregation.
[0011]
[Means for Solving the Problems]
In the present invention, Au: 39.0 to 41.0%, Pd: 4.0 to 6.0%, Cu: 14.0 to 17.0%, Ag: 29.0 to 31. Dental casting alloy characterized by comprising 0%, In: 6.0-8.0%, Ir: 0.03-0.05%, Zn: 1.0-3.0%, and other inevitable impurities It is.
[0012]
That is, the amount of Pd is reduced to 4.0 to 6.0%, and the discoloration due to the sulfuration of Ag is suppressed by increasing the amount of Au to 39.0 to 41.0% and adding In. In addition, since the melting point is 900 ° C. or less, the castability is improved, and the formation of the cast hole and the segregation of the alloy composition, which are concerned, are not observed. If any of the amounts of Au, Pd, and Ag exceeds the above range, the balance is lost and the desired effect cannot be obtained.
[0013]
If the amount of In exceeds the range of the present invention, the mechanical properties are hindered and an intermetallic compound is made brittle. At about 7%, discoloration resistance and corrosion resistance increase. Zn acts as a deoxidizer to improve castability and to improve mechanical properties. Furthermore, Zn improves discoloration resistance. And the range of 1.0-3.0% is suitable.
[0014]
The crystal grains are refined by adding Pd to Ag. However, the progress of the refinement is slow when the amount of Pd is in the range of 4.0 to 6.0%. At that time, the addition of a small amount (0.03 to 0.05%) of Ir further enhances the effect of miniaturization.
[0015]
And when this invention alloy was subjected to wave analysis, it was No. in Table 1. 2 and No. It was also found that there was no effect on the living body.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described together with comparative examples.
Example alloys and comparative example alloys having the compositions shown in Table 2 below were prepared. The melting temperature is also shown.
[0017]
[Table 2]

[0018]
The example alloy of the present invention has a lower melting temperature than the comparative example alloy. This indicates that the castability is good.
[0019]
Next, both Vickers hardnesses were tested. Hardness was examined in three stages after casting, softening and curing.
[0020]
In the case of the example alloy, the softening treatment was quenched in water at 700 ° C. × 10 minutes, and in the case of the comparative example alloy, it was quenched in water at 800 ° C. × 10 minutes.
[0021]
In the case of the example alloy, the hardening treatment was gradually cooled at 350 ° C. for 15 minutes, and in the case of the comparative example alloy, it was gradually cooled at 350 ° C. for 20 minutes.
The results are shown in Table 3.
[0022]
[Table 3]

[0023]
The example alloy subjected to the hardening heat treatment was corroded with a solution of 5 ml of nitric acid + 50 ml of hydrochloric acid for 20 minutes, and a metallographic photograph of the surface was taken. This is shown in FIG. In FIG. 1, (a) is a photograph of 100 times, and (b) is a photograph of 400 times. As can be seen from these photographs, the example alloys have a solid solution structure, and it is clearly shown that the AuCu ordered lattice is precipitated from the grain boundary by aging in the case of the hardening treatment. This increases the strength, decreases the elongation and makes the improvement in mechanical properties clear.
Table 4 shows the mechanical properties of the alloy of the present invention in comparison with the comparative alloy.
[0024]
[Table 4]

[0025]
FIG. 2 and FIG. 3 show test data obtained by conducting a proof test of the alloy of the present invention using an alloy rod having a diameter of 1.92 mm. FIG. 2 shows test data of yield strength after the softening treatment, and FIG. 3 shows test data after the hardening treatment.
[0026]
Next, the discoloration test was conducted using a spectroscopic analyzer (manufactured by Minolta). The state of discoloration showed the appearance and the brightness and saturation of the standard color chart. The test piece was fully immersed in a 0.1% sodium sulfide aqueous solution at 37 ° C. for 7 days.
The results are shown in Table 5.
[0027]
[Table 5]

[0028]
As is apparent from Table 5, the change in hue after the color change of the alloy of the present invention was comparable to that of the conventional gold para alloy.
[0029]
【The invention's effect】
The present invention is effective in reducing the cost because the amount of Pd used is reduced. Moreover, the amount of metal elution is small, the wave analysis is highly evaluated, and there is no influence on the living body. Furthermore, since the melting temperature is low, the castability is good, and as seen from the structure photograph, it has excellent characteristics as an alloy for dental casting having no cast hole and alloy composition segregation and no change in color after discoloration.
[Brief description of the drawings]
FIG. 1 shows a surface metallographic structure of a heat treatment of an alloy of the present invention (a) at a magnification of 100, and (b) where the crystal grains are refined is a photo at a magnification of 400.
FIG. 2 is a graph showing the relationship between stress and elongation of the alloy bar of the present invention softened at 700 ° C.
FIG. 3 is a graph showing the relationship between stress and elongation of the alloy bar of the present invention that has been hardened at 350 ° C. as in FIG.

Claims (1)

Based on weight percent, Au: 39.0 to 41.0%, Pd: 4.0 to 6.0%, Cu: 14.0 to 17.0%, Ag: 29.0 to 31.0%, In An alloy for dental casting comprising: 6.0 to 8.0%, Ir: 0.03 to 0.05%, Zn: 1.0 to 3.0%, and other inevitable impurities.

Images