CH708928A2 - Solid amorphous alloy based on beryllium-free zirconium. - Google Patents

Abstract

The invention relates to a solid amorphous alloy based on zirconium or / and hafnium, free of beryllium, with addition of silver, gold and / or platinum to increase its critical diameter. The invention also relates to a timepiece or jewelry component made of said amorphous alloy.

Description

Field of the invention

[0001] The invention relates to a solid amorphous alloy.

[0002] The invention also relates to a timepiece component made from such an alloy.

The invention relates to the fields of watchmaking, jewelry, and jewelry, in particular for structures: watch cases, middle parts, plates, glasses, pushers, crowns, buckles, bracelets, rings, buckles ears and others.

Background of the invention

Amorphous alloys are increasingly used in the fields of watchmaking, jewelry, and jewelry, in particular for structures: watch cases, middle parts, plates, bezels, pushers, crowns, buckles , bracelets, and others.

[0005] Components for external use, intended to be in contact with the user's skin, must comply with certain constraints, in particular due to the toxicity or allergenic effects of certain metals, in particular beryllium and nickel. Despite the particular intrinsic qualities of such metals, efforts are made to place on the market, at least for the components liable to come into contact with the user's skin, alloys comprising little or no beryllium or nickel. .

[0006] Massive amorphous alloys based on zirconium have been known since the 90s. The following publications relate to such alloys:

[0007] [1] Zhang, et al., Amorphous Zr-AI-TM (TM = Co, Ni, Cu) Alloys with Significant Supercooled Liquid Region of Over 100 K, Materials Transactions, JIM, Vol. 32, No. 11 (1991) pp. 1005–1010.

[0008] [2] Lin, et al., Effect of Oxygen Impurity on Crystallization of an Undercooled Bulk Glass Forming Zr-Ti-Cu-Ni-AI Alloy, Materials Transactions, JIM, Vol. 38, No. 5 (1997) pp. 473-477.

[0009] [3] US Patent 6,592,689.

[0010] [4] Inoue, et al., Formation, Thermal Stability and Mechanical Properties of Bulk Glassy Alloys with a Diameter of 20 mm in Zr- (Ti, Nb) -AI-Ni-Cu System, Materials Transactions, JIM, Flight. 50, No. 2 (2009) pp. 388–394.

[0011] [5] Zhang, et al., Glass-Forming Ability and Mechanical Properties of the Ternary Cu-Zr-AI and Quaternary Cu-Zr-AI-Ag Bulk Metallic Glasses, Materials Transactions, Vol. 48, No. 7 (2007) pp. 1626–1630.

[0012] [6] Inoue, et al., Formation of Icosahedral Quasicrystalline Phase in Zr-Al-Ni-Cu-M (M = Ag, Pd, Au or Pt) Systems, Materials Transactions, JIM, Vol. 40, No. 10 (1999) pp. 1181–1184.

[0013] [7] Inoue, et al., Effect of Additional Elements on Glass transition Behavior and Glass Formation tendency of Zr-AI-Cu-Ni Alloys, Materials Transactions, JIM, Vol. 36, No. 12 (1995) pp. 1420–1426.

The amorphous alloys with the best aptitudes for vitrification, aptitude commonly referred to under the term GFA used hereafter (glass-forming ability), are found in the systems: - Zr-Ti-Cu-Ni-Be (for example LM1 b, Zr44Ti11Cu9.8Ni10.2Be25), - and Zr-Cu-Ni-Al.

[0015] Due to the toxicity of beryllium, alloys with beryllium cannot be used for applications in contact with the skin, such as clothing or the like. However, amorphous zirconium-based alloys without beryllium generally show critical diameters which are smaller than those of alloys with beryllium, which is unfavorable for the production of massive parts. The best composition in terms of critical diameter (Dc) and difference ΔTx between the crystallization temperature Tx and the glass transition temperature Tg (supercooled liquid region) in the Zr-Cu-Ni-AI system is the alloy Zr65Cu17.5Ni10Al7.5 [1].

Modifications are still known where the GFA has been improved by adding titanium and / or niobium: - Zr52.5Cu17.9Ni14.6AI10Ti5 (Vit105) [2] - Zr57Cu15.4Ni12.6AI10Nb5 (Vit106) and Zr58.5Cu15.6Ni12.8Al10.3Nb2.8 (Vit106a) [3] - Zr61Cu17.5Ni10AI7.5Ti2Nb2 [4]

In general, this addition of titanium and / or niobium increases the critical diameter of the alloys, on the other hand the modification greatly reduces the gradient ΔTx and thus the process window for a possible hot deformation of these alloys. In addition, given its very high melting point (2468 ° C), niobium is not easy to melt, which complicates the manufacture of a homogeneous alloy.

[0018] It is also known that adding silver in ternary Zr-Cu-Al alloys increases the critical diameter. In particular for modifications of the composition Zr46Cu46AI8, for example Zr42Cu42Al8Ag8 [5].

On the other hand, because of the high level of copper and the absence of nickel, these alloys do not resist corrosion very well and even have a tendency to discolor (or / and blacken) over time at room temperature .

In addition, it is known that the addition of more than 5% of silver, gold, palladium or platinum, in amorphous Zr-Cu-Ni-Al alloys stimulates the formation of quasi-crystals during devitrification of the alloy by a heat treatment between Tget Tx [6].

In the publication [7] the effect of an additional element M (M = Ti, Hf, V, Nb, Cr, Mo, Fe, Co, Pd or Ag) on the GFA of an alloy Zr- Cu-Ni-AI-M has been tested.

[0022] The results show that only titanium, niobium and palladium increase the critical diameter of the alloy, but at the same time greatly reduce the ΔTx. No specific effect is cited for adding silver to the alloy.

The documents below include amorphous alloys based on zirconium with silver or gold.

[0024] The documents US 5,980,652 and US 5,803,996 describe alloys of the type: Zrbal- (Ti, Hf, Al, Ga) 5-20- (Fe, Co, Ni, Cu) 20-40- (Pd, Pt, Au, Ag) 0-10 and more particularly alloys with palladium and / or platinum, a single example citing an input of 1% gold or 1% silver, without appreciation of the effect of this input on the increase in the critical diameter.

[0025] Document EP 0 905 268 describes alloys of the type: (Zr, Hf) 25-85- (Ni, Cu, Fe, Co, Mn) 50-70-Al> 0-35-T> 0-15 where T is an element with a negative enthalpy of mixing with one of the other elements, and is chosen from the following group: T = Ru, Os, Rh, Ir, Pd, Pt, V, Nb, Ta, Cr, Mo, W, Au, Ga, Ge, Re, Si, Sn or Ti. This document shows only one example with palladium. It does not demonstrate a positive effect of T elements on Dcet ΔTx.

[0026] Document EP 0 905 269 describes a process for manufacturing a multi-phase alloy (14–23% crystalline phase in an amorphous matrix) by heat treatment of Zr25-85-Ni, Cu) 5-70 -AI> 0-35-Ag> 0-15.

CN 101 314 838 documents describe alloys of the type: Zr41-63-CU18-46-Ni1.5-12.5-AI4-15-Ag1.5-26

[0028] In short, the effects of adding silver or gold at low concentration in such amorphous alloys are poorly understood, and have not been the subject of specific investigations in the literature.

Summary of the invention

[0029] The invention proposes to increase the critical diameter of amorphous alloys based on zirconium without beryllium, while keeping a high value of ΔTx.

The invention relates to a solid amorphous alloy based on zirconium and / and hafnium, free of beryllium, with the addition of silver, gold and / or platinum to increase its critical diameter.

[0031] To this end, the invention relates to a solid amorphous alloy, characterized in that it is free of beryllium, and that it consists, in atomic% values, of:

[0032] The invention also relates to a timepiece or jewelry component made from such an alloy.

Brief description of the drawings

[0033] Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, with reference to the accompanying drawings, where: FIG. 1 diagrammatically represents the measurement of the critical diameter in a conical sample; fig. 2 schematically shows a timepiece made of an alloy according to the invention.

Detailed description of the preferred embodiments

The invention relates to the fields of watchmaking, jewelry, and jewelry, in particular for structures: watch cases, middle parts, plates, glasses, pushers, crowns, buckles, bracelets, rings, buckles ears and others.

[0035] The invention proposes to produce amorphous steels without beryllium, designed to exhibit properties similar to those of amorphous alloys containing beryllium. Hereinafter, “beryllium-free alloy” will be called an alloy free of beryllium, and “nickel-free alloy” an alloy comprising less than 0.5% by atomic% of nickel.

By "free of beryllium" is meant that its content is preferably zero, if not very low, in the same way as impurities, and preferably less than 0.1%.

[0037] It is therefore a question of researching the manufacture of alloys which contain elements which substitute for beryllium, and which have high values of the critical diameter Dcet of the gradient û Tx.

[0038] The invention also relates to a solid amorphous alloy based on zirconium, without beryllium, with the addition of silver or / and gold or / and platinum to increase the critical diameter Dc.

[0039] More particularly, the invention relates to a solid amorphous alloy, characterized in that it is free from beryllium, and that it consists, in atomic% values, of:

If we know many amorphous compositions based on zirconium, the development of an amorphous alloy according to the composition of the invention produces an effect which is new and very surprising, since in particular 2% of an additive is sufficient to significantly increase the critical diameter.

The effect of the range from 0.5% to 4.5% of the second filler metal chosen from a second set comprising silver, gold, and platinum is clear: the addition to the alloying one or the other, or more, of these elements increases the critical diameter compared to an alloy composition devoid of these additives, without decreasing the ΔTx.

A transition zone showing a negative gradient of the critical diameter begins at around 4.5%, and, beyond 5%, the critical diameter is significantly reduced compared to the optimum quantity which is between the lower threshold of 0.5 %, where the influence of the input of the second filler metal begins to be visible, and this upper threshold of 4.5%.

[0043] The range of 1.0% to 4.0% is favorable, and very good results have been obtained in the range of 1.5% to 3.8%. More specifically, the gold rate is between 1.5% and 2.5%. More particularly, the level of platinum is between 1.5% and 2.5%. More specifically, the silver rate is between 1.0% and 3.8%.

In a particular embodiment, the total of zirconium and hafnium in the base is limited to 60%.

[0045] In a particular variant, the alloy according to the invention does not contain titanium.

[0046] In a particular variant, the alloy according to the invention does not contain niobium.

[0047] In a particular variant, the alloy according to the invention contains neither titanium nor niobium.

[0048] Palladium did not show any particular positive effect during the development of the invention, unlike the metals of the second set: silver, gold, and platinum. It is possible to integrate it into this second set, but its content should preferably remain very low, in particular less than 1.0%.

A non-limiting example of an embodiment is described below: charges of approximately 70 g of alloy are prepared in an arc furnace using pure elements (purity greater than 99.95%). The pre-alloy thus obtained is then remelted in a centrifugal casting machine and cast in a copper mold in the form of a cone (maximum thickness 11 mm, width 20 mm, opening angle 6.3 °.

A measurement of the glass transition and crystallization temperature by DSC is carried out on samples taken at the end of each cone. A metallographic section is made in the middle of each cone in the direction of its length to measure the critical diameter Dc *, where Dc * corresponds to the thickness of the cone at the place where the crystalline zone begins, as visible in the figure. 1.

The following table summarizes the tests carried out (the compositions in italics represent compositions known from the literature). It can be seen that with the right amount of addition of silver, gold, or platinum, the critical diameter Dc * can be significantly increased compared to base alloys without these additives. In addition, these additives do not reduce the ΔTx.

[0052]

[0053]

More specifically, the alloys which follow have given particularly satisfactory results: Zr62Cu15Ag3Ni10AI10, Zr58.5Cu15.6Ni12.8AI10.3Ag2.8, Zr57.9Cu15.44Ni12.67AM 0.9Ag3.8 Zr52.5Ti2.5Cu15.9Ag2Ni14.6AI12.5 Zr52.5Ti2.5Cu15.9Au2Ni14.6AI12.5 Zr52.5Ti2.5Cu15.9Pt2Ni14.6AI12.5 Zr52.5Ti2.5Cu16.9Ag1Ni14.6AI12.5 Zr52.5Ti2.5Cu14.9Ag3Ni14.6AI12.5 Zr52.5Nb2.5Cu15.9Ag2Ni14.6AI12.5

A first favorable subfamily relates to a total of zirconium and hafnium contents greater than 57.0%, with a total of the first input metals less than 0.5%.

[0056] A second favorable subfamily relates to a total of the zirconium and hafnium contents of less than 53.0%, with a total of the first input metals of between 2.0% and 3.0%.

[0057] In other variations of the invention, still other elements such as iron and manganese are incorporated.

The search for a compromise makes it possible to identify the best composition, in particular with an ideal silver content, which is favorable because of its lower cost than that of gold and platinum, while providing the desired effects.

[0059] For optimization of the alloy, several rules were determined during the experiment. Particularly favorable results have been obtained with:

[0060] The question of incorporating nickel into the alloy arises because of the allergenic effects of nickel taken alone or as an alloy composition with certain other metals. However, the presence of nickel in an amorphous alloy is favorable for obtaining amorphous zirconium-based alloys with high critical diameters and with good anti-corrosion properties. By analogy, stainless steels also contain a high level of nickel, and are widely used in jewelry and watchmaking.

The important constraint to be observed is that the alloy obtained satisfies the nickel release test according to standard EN1811.

[0062] In a particular variant of the invention, the alloy contains less than 0.5% nickel.

We understand that it is not enough to replace nickel with another metal to obtain equivalent characteristics. Elements of neighboring atomic radius are iron, cobalt, palladium, manganese and chromium. This therefore leads to rethinking the complete composition of the amorphous alloy.

[0064] The invention also relates to a second solid amorphous alloy, characterized in that it is free of beryllium, and that it consists, in atomic% values, of:

[0065] The invention also relates to a timepiece or jewelry component made from such an alloy according to the invention, or a timepiece or jewelry piece, in particular a watch, or a bracelet, or the like.

Claims (20)

1. Solid amorphous alloy, characterized in that it is free from beryllium, and that it consists, in values in atomic%, of: A base composed of zirconium and / or hafnium, with a total zirconium and hafnium: minimum value 50%, maximum value 63%; A first filler metal, the value of the total of said at least one filler metal or said first filler metals being between: minimum value 0%, maximum value 4.5%, said at least one first metal delivery member being selected from a first set comprising titanium, niobium, and tantalum, the niobium value being less than 2.5%; A second filler metal, the value of the total of said at least one second filler metal or said second filler metals being between: minimum value 0.5%, maximum value 4.5%, said at least one second metal delivery member being selected from a second set comprising silver, gold, and platinum; A third filler metal, the value of the total of said at least one third filler metal or said third filler metals being between: minimum value 8.5%, maximum value 17.5%, said at least one third metal of intake being selected from a third set comprising nickel, cobalt, manganese, and iron; - aluminum: minimum value 9%, maximum value 13%; - copper and unavoidable impurities: the complement at 100%, but less than 18%. 2. An alloy according to claim 1, characterized in that the value of the total of said at least one second filler metal or said second filler metals in atomic% is between: minimum value 1.0%, maximum value 4, 0%. 3. An alloy according to claim 2, characterized in that the value of the total of said at least one second filler metal or said second filler metals in atomic% is between: minimum value 1.5%, maximum value 3, 8%. 4. Alloy according to one of claims 1 to 3, characterized in that the gold content in atomic% is between 1.5% and 2.5%. 5. Alloy according to one of claims 1 to 3, characterized in that the platinum content in atomic% is between 1.5% and 2.5%. 6. Alloy according to one of claims 1 to 3, characterized in that the silver content in atomic% is between 1.0% and 3.8%. 7. Alloy according to one of the preceding claims, characterized in that the atomic value of the total zirconium and hafnium in the base is less than or equal to 60%. 8. Alloy according to one of the preceding claims, characterized in that the value in atomic% of the total of said at least one first filler metal or said first filler metals is between: minimum value 2.5%, value max 4.5%. 9. Alloy according to one of the preceding claims, characterized in that the aluminum content is greater than 10.0%. 10. Alloy according to one of the preceding claims, characterized in that the ratio of the zirconium content to the copper: Zr / Cu, is between 3.0 and 5.0. 11. Alloy according to one of the preceding claims, characterized in that the ratio of the zirconium content to the total copper and nickel: Zr / (Cu + Ni) is between 1.5 and 3.0. 12. Alloy according to one of the preceding claims, characterized in that the ratio of the total contents in atomic% zirconium, hafnium, titanium, niobium, tantalum, total levels of atomic percent copper and nickel: (Zr, Hf, Ti, Nb, Ta) / (Cu + Ni) is between 1.5 and 3.0. 13. Alloy according to one of the preceding claims, characterized in that said alloy does not contain titanium. 14. Alloy according to one of the preceding claims, characterized in that said alloy does not comprise niobium. 15. Alloy according to one of the preceding claims, characterized in that said alloy comprises no titanium nor niobium. 16. An alloy according to claim 1, characterized in that the total content of zirconium and hafnium in atomic% is greater than 57.0%, and in that the total of said first filler metals in atomic% is less than 0 , 5%. 17. An alloy according to claim 1, characterized in that the total content of zirconium and hafnium in atomic% is less than 53.0%, and in that the total of said first filler metals in atomic% is between 2.0% and 3.0%. 18. An alloy according to claim 1, characterized in that it comprises less than 0.5% nickel in atomic%. Solid amorphous alloy, characterized in that it is free from beryllium, and consists, in atomic%, of: A base composed of zirconium and / or hafnium, with a total zirconium and hafnium: minimum value 50%, maximum value 63%; A first filler metal, the value of the total of said at least one filler metal or said first filler metals being between: minimum value 0%, maximum value 4.5%, said at least one first metal of a feed being selected from a first set comprising titanium, niobium, and tantalum, the niobium value being less than 2.5%; A second filler metal, the value of the total of said at least one second filler metal or said second filler metals being between: minimum value 0.5%, maximum value 4.5%, said at least one second metal of intake being selected from a second set comprising silver, gold, palladium and platinum; A third filler metal, the value of the total of said at least one third filler metal or of said third filler metals being between: minimum value 8.5%, maximum value 17.5%, said at least one third metal of said intake being selected from a third group comprising chromium, cobalt, manganese, and iron; - aluminum: minimum value 9%, maximum value 13%; - and unavoidable impurities: the complement at 100%, but less than 18%. 20. Watchmaking or jewelery component made of an amorphous alloy according to one of the preceding claims.