DE102011001783B4 - Spring for a mechanical clockwork, mechanical clockwork, clock with a mechanical clockwork and method of manufacturing a spring - Google Patents

Abstract

Spring for a mechanical watch movement, the spring comprising an amorphous alloy having a composition consisting of NiaCObFecCrdBeSifCgPhMoiNbkVlTamWn,with0 at% ≤ c ≤ 25.0 at%, 2.0 at% ≤ d ≤ 21.0 at%, 1.0 at% ≤ e ≤ 20.0 at%, 0 at% ≤ f ≤ 20.0 at%, 0 at% ≤ g ≤ 20.0 at%, 0 at% ≤ h ≤ 20.0 atomic %, 0 atomic % ≤ i ≤ 5.0 atomic %, 0 atomic % S k ≤ 5.0 atomic %, 0 atomic % ≤ l ≤ 5.0 atomic %, 0 at% ≤ m ≤ 5.0 at%, 0 at% ≤ n ≤ 5.0 at%; incidental impurities ≤ 1.0 wt%; remainder Ni and/or Co, where 15.0 at.% < e + f + g + h < (0.033 x2- 1.2 x + 32) at.%, where x is the Cr content in at. % is.

Description

The invention relates to springs for a mechanical clockwork, in particular winding or mainsprings, a mechanical clockwork with a spring, a clock with a mechanical clockwork, a method for producing a spring and the use of an amorphous alloy in a spring.

Elevator springs or mainsprings act as energy stores and use the possibility of every material to store energy in the form of elastic energy. For example, mechanical watches have mainsprings, winding springs and mainsprings that are used as energy stores and can generate torque.

This energy is introduced by an elastic, mechanical stress on the spring material, typically by being pulled up, which can be done manually or automatically, for example by oscillating movements and/or the influence of gravity. A high energy storage capacity provides the watch or the instrument with a high rate including a power reserve. On the material side, this is achieved first of all by a high elasticity limit or high mechanical strength of the material used.

wobei V das Volumen der Feder, σ_max die Elastizitätsgrenze und E der Elastizitätsmodul des Federwerkstoffes ist.The following formula for spring energy W or the energy storage capacity of a winding and mainspring shows that both the elastic limit and the modulus of elasticity of the material used are important for the energy storage capacity: $$W=V\frac{{\sigma }^2{}_{\text{Max}}}{E},$$

where V is the volume of the spring, σ _max is the elastic limit and E is the modulus of elasticity of the spring material.

In addition to the elastic limit, the modulus of elasticity also influences the spring energy and thus the energy storage capacity. In contrast to the elastic limit, however, a lower modulus of elasticity is required for a maximum energy storage capacity of the mainspring with a comparable elastic limit.

wobei ε_max die maximale elastische Dehnung des Federwerkstoffes ist.The formula for the energy storage capacity of a spiral spring can be converted into the following formula using the equation σ _max =E ε _max : $$W=V\frac{{\sigma }^2{}_{\text{Max}}}{E}=V\cdot {\sigma }_{\text{Max}}\cdot e_{\text{Max}},$$

where ε _max is the maximum elastic expansion of the spring material.

Assuming that each turn of a winding and mainspring of thickness d can be described by a simple circle with radius R (radius of curvature), a maximum elongation (elongation limit) of the outermost fiber of the spring results $$e_{\text{Max}}=\frac{\Delta l}{l}=\frac{2\pi \left(R+\mathrm{i.e}/2\right)-2\pi R}{2\pi R}=\frac{\mathrm{i.e}}{2R}.$$

In this way, the energy storage capacity of a winding and mainspring can be maximized by a smaller radius of curvature of the hairspring. This means that the spring material is subject to greater stress up to its expansion limit, which often leads to a shorter service life for the spring element.

A further possibility in addition to the elastic limit, the modulus of elasticity and the elongation limit as material parameters for influencing the energy storage capacity is the spring volume V or the spring geometry, i.e. width or thickness. In many applications, however, there is only limited space available for the winding and mainspring, so that the possibility of increasing the energy storage capacity via the spring volume is often limited or not available.

A suitable spring material for winding and mainsprings is characterized by a high limit of elasticity and a low modulus of elasticity. With known crystalline materials however, the elastic limit and the elastic modulus cannot be adjusted independently. As a rule, an increase in the elastic limit is accompanied by an increase in the modulus of elasticity.

In addition to the mechanical characteristics of elastic limit, modulus of elasticity and elongation limit, good oxidation and corrosion resistance as well as non-magnetic, i.e. non-ferromagnetic properties at typical operating temperatures of the spring are important characteristics of the materials used in mainsprings, winding springs and mainsprings.

Steels, e.g. martensitic and/or cold-formed carbon steels and hardenable Cr-Ni steels, and in particular precipitation-hardened Co-Ni-Cr alloys are used in mainsprings, winding springs and mainsprings, which are characterized by their low permanent deformation and reduced indicate risk of breakage. Although carbon steel springs have a high elastic limit and high plastic elongation, they are not sufficiently resistant to corrosion under unfavorable climatic conditions.

Springs provide elastic elements that return to their original position after being pulled, pressed or bent. Due to these elastic stresses, energy is stored in the material or released again by the material. Typically, stored forces or torques can thus be applied with a time delay and in a controlled manner.

Amorphous materials are particularly suitable materials for winding or mainsprings for energy storage. They are generally characterized by very high strength, which is close to the theoretically possible strength due to the lack of dislocations. With elasticity limits in the range of typically 4000 MPa, they achieve strengths that cannot be achieved by crystalline materials. In addition, thanks to the lower melting points, which are typically 500°C-1100°C, they have a relatively low modulus of elasticity. This is of particular interest with regard to the possibility of storing elastic energy with low damping. The modulus of elasticity in amorphous alloys is typically 25-30% lower than in comparable crystalline materials.

Purely elastic loading and unloading processes (vibrations) of a material are independent of time. As a result, stress σ and strain ε are in "phase" over time, independent of the stress rate. However, typical mechanical stresses cannot usually be considered elastic, since additional time-dependent anelastic mechanisms are involved. In the case of vibrations, for example, there is a time delay between stress and strain, which can be represented by a phase angle δ. These anelastic mechanisms are associated with energy losses through energy dissipation in heat, which reduces the elastic energy stored in the material and thus the energy storage capacity.

The stress σ can be linked to a lossy strain ε* by a complex variable E*, which consists of an energy-storing part E' and an energy-dissipating part E''. The mechanical loss is represented by the factor D (damping) and calculated analytically as the tangent of the phase angle δ: $$D=\text{tan}\delta =\frac{E\text{'}\text{'}}{E\text{'}}.$$

D represents a measure of the mechanical damping during vibrations. The lower the modulus of elasticity of the material, the lower the damping and the losses.

Amorphous materials with their relatively low modulus of elasticity show a lower loss factor and are therefore characterized as particularly suitable spring materials for storing elastic energy.

Known methods use lamination and gluing processes to produce an amorphous winding and mainspring. Individual amorphous strips with a typical thickness of 20-50 µm are glued together in order to achieve the spring thickness of 50-200 µm typically required for mainsprings. However, the spring also contains organic components or crystalline laminating partners, which means that the spring cannot fully exploit the advantages of amorphous materials for mainsprings. Such methods for producing amorphous mainsprings are from U.S. 6,843,594 B1 known.

Furthermore, from the U.S. 2009/0303842 A1 a process for the production of mainsprings from an amorphous Ni ₅₃ Nb _2o Zr _e Ti _lo Co ₆ Cu ₃ alloy is known, in which from the molten alloy using a PFC process (PFC, planar flow casting) strips with a thickness between 50 and 150 µm can be produced. The strips are brought to the typical lengths and widths of the mainspring by means of wire EDM. Shaping takes place by winding the strips onto a holder with subsequent heat treatment.

However, the high Nb content leads to increased production costs. In addition, the alloy composition mentioned contains Zr and Ti for better glass formation, which have a very high oxygen or nitrogen affinity and are therefore only produced or processed under vacuum or inert gas, i. H. heat treated, can be. The production only under vacuum and / or partially under protective gas is extremely complex and expensive, especially in commercial quantities. In addition, the surface quality of such alloys produced under vacuum or inert gas is often not sufficient for use as a spring element or mainspring.

The pamphlet U.S. 4,116,682 A discloses an alloy containing at least one of amorphous iron, nickel, cobalt, chromium and manganese. The pamphlet DE 23 663 26 C2 discloses an amorphous nickel-iron base alloy. The pamphlet EP 0 026 237 A discloses an amorphous alloy containing zirconium and at least one of iron, cobalt and nickel. The pamphlets DE 23 641 31 C2 and U.S. 3,856,513 A each disclose amorphous alloys. The pamphlet DE 28 09 837 A1 discloses methods of making amorphous metal ribbons. The pamphlet DE 600 13 078 T2 discloses a nickel base alloy article containing chromium, boron and silicon. The pamphlets DE 698 36 411 T2 and EP 2 351 864 A1 each reveal a clock. The pamphlets CH 700 812 B1 and WO 2010/055 943 A1 each disclose a spring.

The object of the invention is to specify springs for a mechanical clockwork which have a high strength and a low modulus of elasticity and are suitable for large-scale production in air. Furthermore, it is the object of the invention to specify corresponding methods for producing a spring.

These objects are solved with the subjects of the independent claims. Advantageous developments of the invention result from the dependent claims.

According to the invention there is provided a spring for a mechanical timepiece, the spring comprising an amorphous alloy having a composition consisting of Ni _a Co _b Fe _c Cr _d B _e Si _f C _g P _h Mo _i Nb _k V _l Ta _m W _n , With
0 at% ≤ c ≤ 25.0 at%,
2.0 at% ≤ d ≤ 21.0 at%,
1.0 at% ≤ e ≤ 20.0 at%,
0 at% ≤ f ≤ 20.0 at%,
0 at% ≤ g ≤ 20.0 at%,
0 at% ≤ h ≤ 20.0 at%,
0 at% ≤ i ≤ 5.0 at%,
0 at% ≤ k ≤ 5.0 at%,
0 at% ≤ 1 ≤ 5.0 at%,
0 at% ≤ m ≤ 5.0 at%,
0 at% ≤ n ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Balance Ni and/or Co, where 15.0 at% < e + f + g + h < (0.033 x ² - 1.2 x + 32) at%, where x is the content of Cr in at -% is. The numerical value of x is therefore equal to the numerical value of d. The relationship 0 ≤ b / (a + b) ≤ 1 applies to the ratio of Co to Ni.

The present invention provides a spring made of amorphous alloys, the composition of which advantageously allows large-scale production and/or processing in air, ie in particular under normal atmospheric conditions. Compared to the one from the U.S. 2009/0303842 A1 With the known alloy, production and/or processing, in particular heat treatment, under vacuum or inert gas is not necessary with the alloy mentioned.

Furthermore, it was recognized within the scope of the present invention that the above-mentioned relationship between the content of Cr and the total metalloid content, ie the content of Si + B + C + P, advantageously a production of the spring in sufficiently large thicknesses, typically in a Foil thickness of at least 50 µm possible. The elements or element groups mentioned could otherwise have a negative effect on the maximum possible manufacturing thickness if the contents are too high. The mentioned content of Cr advantageously brings about an improved corrosion resistance of the spring. The lower limit for the total metalloid content is appropriate to ensure good glass forming properties for the manufacture of the spring.

The spring according to the invention, which has the amorphous material, is also characterized by very high strength and a low modulus of elasticity. As a result, significantly more energy can be stored with the same volume or size of the spring than with known crystalline alloys.

The alloy may contain incidental impurities up to 1% by weight. Impurities are in practice measured in weight percent and hence this is the unit used for impurities. In principle, any element that is not explicitly mentioned in the above-mentioned composition can be designated as an impurity. Elements commonly measured as impurities are Al, Ti, Zr, Cd, Se and S.

The alloy is preferably essentially free of reactive elements, in particular zirconium, titanium and aluminum. “Essentially free from” is understood to mean less than 0.1 percent by weight.

In a preferred embodiment, the composition consists essentially of Ni _a Fe _c Cr _d B _e Si _f Mo _l Nb _k , With
0 at% ≤ c ≤ 5.0 at%,
4.0 at% ≤ d ≤ 12.0 at%,
5.0 at% ≤ e ≤ 18.0 at%,
0 at% ≤ f ≤ 10.0 at%,
0 at% ≤ i ≤ 5.0 at%,
0 at% ≤ k ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Rest Ni. Thus, in this embodiment, b=g=h=l=m=n=0 at%.

• 2,0 Atom-% ≤ c ≤ 3,0 Atom-%,
• 6,0 Atom-% ≤ d ≤ 10,0 Atom-%,
• 7,0 Atom-% ≤ e ≤ 16,0 Atom-%,
• 2,0 Atom-% ≤ f ≤ 8,0 Atom-%,
• 2,0 Atom-% ≤ i ≤ 3,0 Atom-%,
• 2,0 Atom-% ≤ k ≤ 3,0 Atom-%.

In a further preferred embodiment:

• 2.0 at% ≤ c ≤ 3.0 at%,
• 6.0 at% ≤ d ≤ 10.0 at%,
• 7.0 at% ≤ e ≤ 16.0 at%,
• 2.0 at% ≤ f ≤ 8.0 at%,
• 2.0 at% ≤ i ≤ 3.0 at%,
• 2.0 at% ≤ k ≤ 3.0 at%.

In particular, the amorphous alloy may have a composition selected from the group consisting of Ni ₆₇ Cr _6.5 Fe _2.5 Si ₈ B ₁₆ , Ni _71.1 Cr _6.6 Si _7.8 B _14.5 , Ni ₇₀ Cr ₈ Si ₈ B ₁₄ and Ni ₇₀ Cr _a Si ₇ B ₁₄ Mo ₁ .

Furthermore, the invention relates to a spring for a mechanical clockwork, the spring having an amorphous alloy with a composition consisting essentially of Ni _a Cr _b Si _r P _d B _e Fe _f Mo _g Nb _h , With
4.0 at% ≤ b ≤ 21.0 at%,
0 at% ≤ c ≤ 10.0 at%,
5.0 at% ≤ d ≤ 18.0 at%,
1.0 at% ≤ e ≤ 5.0 at%,
0 at% ≤ f ≤ 5.0 at%,
0 at% ≤ g ≤ 5.0 at%,
0 at% ≤ h ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Rest Ni exists.

Said spring also comprises an amorphous alloy, the composition of which advantageously allows manufacture and/or processing in air.

It is preferably 15.0 atom %<c+d+e<(0.033×x ² −1.2×x+32) atom %, where x is the Cr content in atom %. The numerical value of x is therefore equal to the numerical value of b.

The alloy may also contain incidental impurities of up to 1% by weight. Any element that is not explicitly mentioned in the above-mentioned composition can in turn be designated as an impurity.

The alloy is preferably essentially free of reactive elements, in particular zirconium, titanium and aluminum. “Essentially free from” is understood to mean less than 0.1 percent by weight.

• 6,0 Atom-% ≤ b ≤ 20,0 Atom-%,
• 1,0 Atom-% ≤ c ≤ 8,0 Atom-%,
• 7,0 Atom-% ≤ d ≤ 16,0 Atom-%,
• 2,0 Atom-% ≤ e ≤ 4,0 Atom-%,
• 2,0 Atom-% ≤ f ≤ 3,0 Atom-%,
• 2,0 Atom-% ≤ g ≤ 3,0 Atom-% und
• 2,0 Atom-% ≤ h ≤ 3,0 Atom-%.

In a preferred embodiment:

• 6.0 at% ≤ b ≤ 20.0 at%,
• 1.0 at% ≤ c ≤ 8.0 at%,
• 7.0 at% ≤ d ≤ 16.0 at%,
• 2.0 at% ≤ e ≤ 4.0 at%,
• 2.0 at% ≤ f ≤ 3.0 at%,
• 2.0 at% ≤ g ≤ 3.0 at% and
• 2.0 at% ≤ h ≤ 3.0 at%.

In particular, the amorphous alloy may have a composition selected from the group consisting of Ni ₆₁ Cr ₁₈ Si ₄ P ₁₃ B ₄ , Ni ₆₅ Cr ₁₇ Si _6.5 P ₉ B _2.5 , Ni ₆₃ Cr ₁₈ Si ₂ P ₁₃ B ₄ and Ni _{62.5 Cr 20} Si ₁ P ₁₄ B _2.5 .

The spring preferably has a thickness d, where 50 μm≦d≦200 μm. This area is particularly suitable for mainsprings or spring ribbons. In this case, the spring preferably has a rectangular cross-sectional geometry or a rectangular cross-section.

In a further embodiment, the spring is S-shaped and/or spiral-shaped in the relaxed state.

The amorphous alloy preferably has a crystallization temperature Tx, where _Tx >400° _C . T _x >450°C is particularly preferred. As a result, a temperature-induced shaping of the spring or the spring ribbon, for example into an S or spiral shape, is possible in a particularly advantageous manner without undesired crystallization and/or brittleness of the amorphous material occurring.

The amorphous alloy preferably has a Vickers hardness HV 0.5 of 775 to 990. The limit values are included in the specified interval.

The spring is preferably designed as a drive spring, in particular as a winding spring.

The invention also relates to a mechanical clockwork that has a spring according to one of the preceding embodiments, and a clock with such a mechanical clockwork. The mechanical clockwork and the clock according to the invention have the advantages already mentioned in connection with the springs according to the invention, which are not repeated here to avoid repetition.

Furthermore, the invention relates to a method for producing a spring according to one of the preceding embodiments, the method having the following steps. There is a melting of the Alloy, wherein the alloy has one of the aforementioned compositions. Further, an amorphous ribbon is formed from the molten alloy. In addition, the amorphous strip is wound onto a first holder in a first winding direction. Further, the coiled tape is heat treated.

For the shaping, the amorphous strip material is thus wound up and heat-treated, as a result of which the S- or spiral shape of the spring is tempered, for example. In the method according to the invention, production and/or processing, in particular heat treatment, under vacuum or inert gas is no longer necessary due to the use of an alloy with a composition according to one of the aforementioned embodiments.

The heat treatment of the coiled strip is thus preferably carried out in air. Furthermore, the melting of the alloy and/or the forming of the amorphous ribbon from the melted alloy preferably takes place in air.

In a further preferred embodiment, the coiled strip is hot-worked at a temperature T, where 0.3×T _x ≦T≦0.7×T _x , where T _x is the crystallization temperature of the amorphous alloy. This temperature range ensures sufficient diffusion for the relaxation required for shaping, which is required for impressing the corresponding mainspring shape.

Furthermore, the hot working of the coiled strip can preferably be carried out at a temperature T, where 150°C≦T≦350°C. In the context of the present invention, it was recognized that at temperatures below 150° C., the temperature is typically not sufficient to activate the diffusion and thus set a spiral shape, for example. At temperatures above 350°C, individual surface crystallites typically begin to crystallize, which can make the strip brittle.

In another embodiment, the amorphous ribbon is also wound onto a second fixture in a second winding direction, the second winding direction being opposite to the first winding direction. The amorphous strip is preferably wound onto a twin mandrel. This embodiment enables an S-shape to be imprinted on the spring in a simple manner.

The first holder and/or the second holder can be designed as a mandrel. In embodiments with a first and second holder, these can be designed as twin mandrels.

In a further advantageous embodiment, the amorphous strip is formed from the molten alloy by means of a rapid solidification process. The amorphous strip is preferably formed from the molten alloy by means of a melt spinning process, which is also referred to as melt spinning or melt spinning.

In another embodiment, the amorphous ribbon is formed from the molten alloy into an amorphous ribbon having a thickness d, where 50 μm≦d≦200 μm. This eliminates in an advantageous manner in which from the U.S. 6,843,594 B1 Known methods required forming of the amorphous alloys, since the geometry of the starting material already corresponds to the spring ribbon geometry. This eliminates the difficult, costly and technically critical forming steps to achieve the thickness mentioned, particularly in the case of so-called bulk amorphous alloys. Also the ones from the U.S. 6,843,594 B1 Known lamination or gluing techniques, in which individual amorphous strips are joined together in order to achieve the thickness required for the spring ribbon, can be omitted with the method according to the invention according to this embodiment.

After forming the amorphous ribbon from the molten alloy, a width of the ribbon can be reduced. This enables a simple realization of a strip material with the narrow width tolerances required in particular for winding springs.

In one embodiment, the width of the amorphous ribbon is reduced by cutting using circular shears. Furthermore, reducing the width of the amorphous ribbon can be done by wire EDM.

The invention also relates to the use of an amorphous alloy in a spring for a mechanical timepiece having a composition consisting essentially of Ni _a Co _b Fe _c Cr _d B _e Si _f C _g P _h Mo _l Nb _k V _l Ta _m W _n , With
0 at% ≤ c ≤ 25.0 at%,
2.0 at% ≤ d ≤ 21.0 at%,
1.0 at% ≤ e ≤ 20.0 at%,
0 at% ≤ f ≤ 20.0 at%,
0 at% ≤ g ≤ 20.0 at%,
0 at% ≤ h ≤ 20.0 at%,
0 at% ≤ i ≤ 5.0 at%,
0 at% ≤ k ≤ 5.0 at%,
0 at% ≤ 1 ≤ 5.0 at%,
0 at% ≤ m ≤ 5.0 at%,
0 at% ≤ n ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Balance Ni and/or Co, where 15.0 at% < e + f + g + h < (0.033 x ² - 1.2 x + 32) at%, where x is the content of Cr in at -% is.

The invention further relates to the use of an amorphous alloy in a spring for a mechanical clockwork having a composition consisting essentially of Ni _a Cr _b Si _c P _d B _e Fe _f Mo _g Nb _h , With
4.0 at% ≤ b ≤ 21.0 at%,
0 at%^c ≤ 10.0 at%,
5.0 at% ≤ d ≤ 18.0 at%,
1.0 at% ≤ e ≤ 5.0 at%,
0 at% ≤ f ≤ 5.0 at%,
0 at% ≤ g ≤ 5.0 at%,
0 at% ≤ h ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Rest Ni exists.

The spring is preferably designed as a drive spring, in particular as a winding spring.

• 1A zeigt eine Aufzugsfeder gemäß einer ersten Ausführungsform der Erfindung;
• 1B zeigt eine Aufzugsfeder gemäß einer zweiten Ausführungsform der Erfindung;
• 1C zeigt eine Aufzugsfeder gemäß einer dritten Ausführungsform der Erfindung;
• 1D zeigt eine Aufzugsfeder gemäß einer vierten Ausführungsform der Erfindung;
• 2 zeigt eine Kraftmomentkennlinie einer Spiralfeder;
• 3 zeigt ein Flussdiagramm eines Verfahrens zur Herstellung einer Aufzugsfeder gemäß einer Ausführungsform der Erfindung;
• 4 zeigt eine DSC-Analyse eines amorphen Bandmaterials mit der Zusammensetzung Ni₆₇Cr₆,₅Fe_2,5Si₈B₁₆ (in Atom- %);
• 5 zeigt eine DSC-Analyse eines amorphen Bandmaterials mit der Zusammensetzung Ni₆₁Cr₁₈Si₄P₁₃B₄ (in Atom-%) .

The invention will now be explained in more detail with reference to the accompanying figures.

• 1A shows a mainspring according to a first embodiment of the invention;
• 1B shows a mainspring according to a second embodiment of the invention;
• 1C shows a mainspring according to a third embodiment of the invention;
• 1D shows a mainspring according to a fourth embodiment of the invention;
• 2 shows a force torque characteristic of a spiral spring;
• 3 shows a flow chart of a method for manufacturing a mainspring according to an embodiment of the invention;
• 4 Figure 12 shows a DSC analysis of an amorphous ribbon material having the composition Ni ₆₇ Cr _{6 .5} Fe _2.5 Si ₈ B ₁₆ (in atomic %);
• 5 shows a DSC analysis of an amorphous ribbon material with the composition Ni ₆₁ Cr ₁₈ Si ₄ P ₁₃ B ₄ (in atomic %) .

1A shows a mainspring 1 according to a first embodiment of the invention.

The mainspring 1 has an S-shape in the relaxed state or is S-shaped in the relaxed state. The mainspring 1 is typically enclosed in a cylindrical housing (not shown in detail), the so-called spring barrel, and is fastened at one end to the wall of this housing and at the other end to its axis, the so-called spring core.

1B shows a mainspring 2 according to a second embodiment of the invention.

In this case, the mainspring 2 has a spiral shape in the relaxed state or is spiral-shaped in the relaxed state.

Combinations of the two embodiments are also possible.

For this shows 1C a mainspring 3 according to a third embodiment of the invention.

In the relaxed state, the mainspring 3 has a so-called semi-inverted shape.

Furthermore shows 1D a mainspring 4 according to a fourth embodiment of the invention.

In the relaxed state, the mainspring 4 has a so-called inverted shape.

The mainsprings according to the 1A until 1D The embodiments shown here have an alloy with one of the compositions mentioned according to the invention, as will be explained further below.

As already explained, various properties are simultaneously of particular importance for the materials used for winding or mainsprings, as they are used in devices and instruments of all kinds, in particular for mechanical watches as energy stores. These criteria are given for both amorphous and crystalline alloys by maximum mechanical strength with sufficient ductility, fracture resistance as well as buckling and bending strength, corrosion and oxidation resistance and non-magnetic properties. The individual criteria are explained in more detail below.

The strength of amorphous alloys typically increases with the content of metalloids, which are also important for the production as amorphous alloys due to their glass-forming ability. For maximum strength, the use of the metalloid boron (B) and, to a lesser extent, silicon (Si) and carbon (C) are of particular importance. These glass-forming elements are particularly preferable to phosphorus (P), which is also suitable for glass formation in amorphous materials, since B in particular, but also Si and C, with comparable contents, bring about significantly greater strength in the amorphous material.

Within the scope of the invention, it was recognized that increasing the total metalloid content above one of the values mentioned above leads to a significant decrease in the maximum possible strip thickness if the alloy is initially produced as an amorphous strip using rapid solidification technology. As a result, the selection of the metalloid content and its composition is of particular importance in the case of amorphous materials for winding or mainsprings.

Other alloying elements are also important for strength. Additions of Cr, Mo, Nb can be alloyed to further increase the strength of the amorphous strip material. However, since these are also associated with a reduction in the maximum possible strip thickness with a completely amorphous microstructure, this group of alloying elements is also of particular importance. The chromium content is particularly important here, as it not only increases strength but is also particularly relevant for corrosion protection and for the magnetic properties, i.e. for non-magnetic mainsprings.

The elements Fe, Ni and Co are of particular importance as the base metal for amorphous strip material produced using rapid solidification technology.

Within the amorphous Fe, Co and Ni-based alloys, the Fe-based materials have the highest strength values with a comparable metalloid content and content of other alloying elements, which means that they should always be considered for spring applications.

Amorphous materials typically exhibit elastic properties that are highly suitable for spring applications. However, it must be taken into account that the amorphous material preferably has at least an 80% degree of amorphity, since the amorphous state enables these favorable elastic properties. If the amorphous material has pronounced crystalline areas or pronounced surface crystallites due to the manufacturing process, these amorphous alloys are very brittle and sensitive to fracture and therefore typically do not meet the requirements for a material for mainsprings.

Such crystalline fractions can arise as a result of insufficient cooling during production as an amorphous starting material or exceeding the maximum thickness that can be produced, at which a completely amorphous microstructure is ensured.

Furthermore, the selection of the amorphous alloys, which is suitable for the production of an amorphous mainspring according to the present invention, is determined by the crystallization temperature. Temperatures above the crystallization temperature of the amorphous material are to be avoided, since the crystallization that then begins leads to brittle material properties.

The process step for setting, for example, the spiral shape of the amorphous mainspring requires a certain temperature in order to temper this spiral shape. The spiral shape is preferably set in a temperature range between 150-350°C, so that the amorphous alloys used preferably have a crystallization temperature greater than 400°C.

The element Cr is typically used to set the required corrosion or oxidation resistance of the amorphous spring material. The corrosion resistance of amorphous alloys is typically better than that of comparable crystalline alloys, since the grain boundaries of crystalline materials, which are often responsible for corrosion attack, are not present in amorphous materials. Another decisive role for the corrosion behavior of vitreous metals is the influence of the metalloids present in amorphous alloys and, also in the case of a dense and homogeneous surface, the passivating effect of the surface layers that form during the corrosion attack.

For example, a chromium content greater than 5% is suitable for adequate corrosion protection. Fe-based amorphous alloys, for example, show a high corrosion resistance from a Cr content of approx. 5 at.%.

Although the corrosion resistance increases with increasing Cr content, this leads to a reduction in the maximum possible strip thicknesses, so that within the scope of the present invention the above-mentioned relationship between the Cr content and the total metalloid content, i.e. the Si + B + content C + P, was recognized.

Furthermore, the materials typically used for mainsprings in mechanical watches should be non-magnetic, since otherwise the accuracy or the general function of the watch or the instrument would be influenced by external magnetic fields or magnetic damping effects.

As already explained, the elements Fe, Co and Ni are fundamentally important as the base material for amorphous alloys. These elements and their alloys are ferromagnetic at room temperature, so that the choice and content of the alloying additions typically shifts the Curie temperature to the range from -20°C to -50°C. This ensures non-magnetic properties of the spring element in the typical temperature range of 0°C to +50°C for mainsprings.

Here again the Ni-Cr-Si-B alloys according to the invention are particularly advantageous since the chromium effectively lowers the Curie temperature even with a content of a few at.%.

For amorphous alloys, as used for the present invention, there are additional additional criteria. The alloys are preferably produced using a melt spinning process in a thickness of 50-200 µm as a strip or foil. Furthermore, the alloys preferably have a sufficiently high crystallization temperature in order to be able to carry out temperature-induced shaping, for example into a spiral shape, without crystallization of the amorphous strip material occurring.

It is therefore particularly advantageous for the present invention that alloy compositions are selected which can be reliably produced using rapid solidification technology in a thickness of preferably 50-200 μm.

In addition, it was recognized within the scope of the invention that the surface quality of alloys produced under vacuum or inert gas, such as those from the U.S. 2009/0303842 A1 are known, is often not sufficient for use as a spring element or mainspring. In contrast, the alloy compositions provided within the scope of the present invention have the advantage that they can be produced in air as an amorphous strip.

A further characteristic of the amorphous winding or mainsprings according to the invention and their production is the temperature-induced setting of the S-shape and/or spiral shape typical of winding springs. This shaping step typically takes place at temperatures of 150-350°C. The temperature of this shaping step must be high enough to set the S and/or spiral shape. Amorphous alloys which have a crystallization temperature of greater than 400° C., preferably greater than 450° C., are therefore particularly suitable.

In addition to the criteria mentioned, for reasons of environmental compatibility it is increasingly important to ensure that no toxic or environmentally critical alloying elements are used. In the field of amorphous materials, this applies in particular to the element beryllium (Be), which can be used as a glass-forming additive.

Taking into account the properties and property relationships set out above, the aforementioned alloy compositions were provided within the scope of the present invention, since they have the property profile specified for amorphous mainsprings according to the invention.

In order to achieve the properties specified for amorphous springs and their production according to the present invention, alloys are particularly important
with a composition consisting essentially of Ni _a Co _b Fe _c Cr _d B _e Si _f C _g P _h Mo _i Nb _k V _l Ta _m W _n , With
0 at% ≤ c ≤ 25.0 at%,
2.0 at% ≤ d ≤ 21.0 at%,
1.0 at% ≤ e ≤ 20.0 at%,
0 at% ≤ f ≤ 20.0 at%,
0 at% ≤ g ≤ 20.0 at%,
0 at% ≤ h ≤ 20.0 at%,
0 at% ≤ i ≤ 5.0 at%,
0 at% ≤ k ≤ 5.0 at%,
0 at% ≤ l ≤ 5.0 at%,
0 at% ≤ m ≤ 5.0 at%,
0 at% ≤ n ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Balance Ni and/or Co, where 15.0 at% < e + f + g + h < (0.033 x ² - 1.2 x + 32) at%, where x is the content of Cr in at -% is significant.

Other alloys which have the combination of properties specified for the amorphous mainspring according to the invention are alloys with a composition which essentially consists of Ni _a Cr _b Si _c P _d B _e Fe _f Mo _g Nb _h , With
4.0 at% ≤ b ≤ 21.0 at%,
0 at% ≤ c ≤ 10.0 at%,
5.0 at% ≤ d ≤ 18.0 at%,
1.0 at% ≤ e ≤ 5.0 at%,
0 at% ≤ f ≤ 5.0 at%,
0 at% ≤ g ≤ 5.0 at%,
0 at% ≤ h ≤ 5.0 at%;
incidental impurities ≤ 1.0% by weight; Rest Ni exists.

In addition to the material properties, these can also be produced in a strip thickness of 50-200 µm as a fully amorphous strip and have a crystallization temperature greater than 400°C. The former alloys typically achieve a higher level of strength than the latter.

2 shows a force torque characteristic of a spiral spring.

wo k eine Konstante abhängig von der Geometrie der Feder, d.h. Dicke, Breite und Länge, und E der Elastizitätsmodul des Federwerkstoffes ist.The so-called force torque characteristic shows the dependence of the force torque M of a spiral spring on the number of coils N and can be calculated using the following equation: $$M=k\cdot E\cdot N,$$

where k is a constant dependent on the geometry of the spring, ie thickness, width and length, and E is the modulus of elasticity of the spring material.

Are winding and mainsprings in the in the 1C and 1D shown semi-inverted or inverted shape, the number of turns with too low, irrelevant torque is reduced to a minimum. The gradient of the force torque characteristic in the area in which the force torque is relevant can also be calculated using the previous equation and is proportional to the modulus of elasticity E. The smaller the modulus of elasticity of the material, the flatter the force torque characteristic. The flatter force torque characteristic provides a more even torque and at the same time, assuming the usable torque is between 50% and 90% of the maximum torque M _max , allows a higher number of turns N(M _90% )-N(M _50% ) to be used and thus to achieve a longer running time, ie a higher energy storage capacity.

As a result, the amorphous materials according to the invention, with very high strength and a low modulus of elasticity, meet the requirements for a material for winding springs with regard to maximum storable spring energy to a particularly high degree.

3 shows a flow chart of a method for manufacturing a mainspring according to an embodiment of the invention.

The alloy compositions according to the invention that have already been explained are used for the method described below for producing the S-shaped and/or spiral spring, for example.

In a step 10, the alloy is melted, the alloy having a composition according to one of the aforementioned embodiments.

Furthermore, in a step 20, the molten alloy is primary formed into an amorphous strip or an amorphous foil. In the embodiment shown, the primary shaping takes place using meltspin technology, in which the molten metal is sprayed onto a rotating copper wheel. The amorphous tape or foil is produced with a thickness between 50-200 µm. In order to achieve these strip thicknesses, which are relatively high for amorphous strip material, in addition to the alloy selection according to the invention, the production parameters casting wheel speed and nozzle slot thickness are adjusted in particular.

In order to use the particularly favorable properties of the amorphous state of the material, care must be taken to ensure that the material has at least a degree of amorphousness greater than 80%. The material is preferably completely amorphous. Typical widths for amorphous strip material produced using the melt spinning process are in the range between 20-100 mm. The strip material is typically wound into rolls or "coils" directly on the melt spin systems using appropriate winding systems.

In the embodiment shown, the amorphous strip is cut open in a further step 30 to the desired width of the spring, from which the spiral spring, for example, is then formed in further process steps. Cutting enables a simple realization of a strip material with the narrow width tolerances required for mainsprings. Furthermore, the natural edge of the amorphous ribbon material can have defects such as nicks or scores or other structural defects. Exact edge quality is also required for highly stressed spiral springs, such as those required by mechanical watches, since any structural defects - especially at the edges of the spring ribbon - can lead to failure due to spring breakage or insufficient spring properties when the amorphous spring is later used. The typical widths for spring ribbons are typically between 0.5-3.0 mm. Circular shears are particularly advantageous for cutting amorphous strip material.

In a step 40, the amorphous strip material is cut to a length of between 200-1000 mm.

After cutting to length, the spring ribbon is wound onto a first holder, for example a mandrel, in a step 50 and heat-treated in a step 60 in order to emboss the spiral shape, which is typical of winding springs and may be semi-inverted or inverted. For an S-shape of the spring, the amorphous strip material is wound onto a first holder and a second holder, preferably onto a twin mandrel, with the direction of winding being different on the individual holders or mandrels.

The heat treatment, which preferably takes place in air, is carried out at a temperature which is high enough on the one hand for the diffusion-controlled relaxation processes to take place and thus to be able to set a permanent impression of the spiral or S-shape. On the other hand care has to be taken that this temperature is not too high in order to avoid crystallization of the metastable amorphous state. The crystallization typically begins on the surface of the amorphous ribbon, in particular at surface defects caused by production. This crystallization causes the spring ribbon to become brittle, making it unsuitable for use as a spiral spring.

The suitable temperature for this heat treatment is largely determined by the crystallization temperature of the amorphous starting material. It was found within the scope of the present invention that the temperature range of 150-350° C. is particularly favorable for tempering the S or spiral shape. The alloys mentioned are therefore particularly advantageous since they can have a crystallization temperature greater than 400.degree. C., preferably greater than 450.degree.

Furthermore, it was found within the scope of the present invention that in the case of amorphous alloys which have a crystallization temperature greater than 400° C., the shaping heat treatment is preferably carried out between 0.3-0.7 T _x , where T _x represents the crystallization temperature. This temperature range ensures sufficient diffusion for the relaxation required for shaping, which is required for impressing the corresponding mainspring shape. In this temperature range, there is still no crystallization of the amorphous material, which is associated with undesirable brittleness of the strip material.

In the embodiment shown, the duration of the heat treatment is between one minute and four hours, depending on the temperature of the heat treatment.

In contrast to the one from the U.S. 2009/0303842 A1 Known manufacturing processes for amorphous springs, the present invention uses special alloy compositions or chemical compositions of the amorphous alloy, which have very high strength, have a crystallization temperature greater than 400°C and are melt-spun as ribbons or foils with a thickness of 50-200 µm with a preferably completely amorphous microstructure can be produced in air or in a reduced proportion of protective gas.

Tests and test results are described below in which material properties of example alloys with compositions according to the present invention and with compositions not according to the invention are determined and compared with one another.

example 1

An alloy according to the invention with the composition Ni ₆₇ Cr _6.5 Fe _2.5 Si ₈ B ₁₆ (in at.%) is first produced in a strip thickness of 80 μm and a casting width of 25 mm as an amorphous strip material by means of the melt spin process. The strip thickness is varied and adjusted in particular by the speed of the casting wheel. A buckling test after manufacture, in which the strip material can be completely kinked without breaking, proves that the strip is completely amorphous or has an amorphous degree of at least 80%. This strip is then cut to a strip width of 3.0 mm using circular shears.

one inside 4 The DSC analysis of this material shown shows the structural and phase transformations. The crystallization temperature is 500°C (peak temperature) or 498°C-509°C (onset temperatures of the crystallization peak), the melting range is 975°C-1035°C.

This material therefore has the high crystallization temperature required for further processing into a spiral spring. This means that a shaping heat treatment can be carried out at 150-350 °C without undesired crystallization of the material occurring.

example 2

An alloy according to the invention of the composition Ni ₆₁ Cr ₁₈ Si ₄ P ₁₃ B ₄ (in at.%) is first produced in a strip thickness of 80 μm and a casting width of 25 mm as an amorphous strip material by means of the melt spin process. The strip thickness is varied and adjusted in particular by the speed of the casting wheel. A buckling test after production, in which the strip material can be completely kinked without breaking, proves that the strip is completely amorphous or has an amorphous degree of at least 80%.

one inside 5 The DSC analysis of this material shown shows the structural and phase transformations. The crystallization temperature is 461°C-470°C (crystallization peak onset temperatures).

In addition to the favorable manufacturing properties, which enable strip thicknesses of 50-200 µm, this alloy has the high crystallization temperature required for further processing into a spiral spring. This means that a shaping heat treatment can be carried out at 150-350°C without undesired crystallization of the material occurring.

Example 3

Various alloys according to the invention and not according to the invention are produced as amorphous strip material in a casting width of 25 mm by means of melt spinning processes. The mechanical properties are then determined by hardness measurement. Since the measurement of the mechanical properties of amorphous strip material is very sensitive to shear forces and these can significantly influence the measurement result, hardness measurement is used in addition to the tensile test as a simple and reproducible method for determining the mechanical properties of amorphous strip material.

In addition to the chemical composition, Table 1 summarizes the mechanical strength (HV0.5) and information as to whether the alloy can be produced in the thickness greater than 50 µm that is relevant for mainsprings. Example alloys in at.% no feet Cr si B P example 1 rest 6.6 7.8 14.5 example 2 rest 8th 8th 14 Example 3 rest 8th 7 14 example 4 rest 14 8th 13 Example 5 rest 17 6.5 2.5 9 Example 6 rest 18 2 4 13 Example 7 rest 20 1 2.5 14 example 8 rest 15.5 6.8 example 9 rest 11 8th Table 1: Mechanical properties and manufacturing properties of various amorphous alloys produced using melt spinning processes; alloys with high strength and producible strip thicknesses greater than 50 μm are particularly suitable for the process according to the invention Example alloys in at.% Mon Nb Hardness HV0.5 Producible in strip thicknesses greater than 50 µm example 1 965 Yes example 2 980 Yes Example 3 1 990 Yes example 4 990 no Example 5 780 Yes Example 6 800 Yes Example 7 775 Yes example 8 3 1020 no example 9 3 1040 no

It can be seen from Table 1 that the amorphous example alloys 1 to 3 according to the invention in particular have a very high degree of hardness and thus mechanical strength, as is required for the material used in winding springs. In addition, these alloys with possible strip thicknesses of more than 50 µm also meet the desired manufacturing criteria. Example alloys 5 to 7 according to the invention can also be produced in these thicknesses, but do not reach the level of strength of example alloys 1 to 3. Example alloys 8 and 9 are characterized by the highest strengths, but they can be produced in a strip thickness greater than 50 μm not possible.

example 4

Various alloys, which have proven to be particularly suitable for the present invention, are produced as amorphous strip material in a casting width of 25 mm using the melt-spin process. The strip thickness is varied in particular by varying the casting wheel speed. The maximum possible strip thickness with a completely amorphous structure is determined by a buckling test after production. The alloys listed can be produced in the particularly advantageous thickness range of 50-200 µm with a largely amorphous microstructure. Table 2: Maximum possible strip thicknesses of various amorphous alloys which have proven to be particularly suitable for the present invention Example alloys in at.% no Cr si B P Mon Maximum strip thickness with (largely) amorphous microstructure [µm] example 1 rest 6.6 7.8 14.5 120 example 2 rest 8th 8th 14 100 Example 3 rest 8th 7 14 1 90 example 4 rest 14 8th 13 60 Example 5 rest 17 6.5 2.5 9 90 Example 6 rest 18 2 4 13 90 Example 7 rest 20 1 2.5 14 100

Example 5

An alloy according to the invention with the composition Ni ₆₇ Cr _6.5 Fe _2.5 Si ₈ B ₁₆ (in at.%), which has a crystallization temperature of 500° C., is first produced in a strip thickness of 100 μm as an amorphous strip material. This strip material is cut open to a width of 3.0 mm using circular shears. After cutting the amorphous ribbon to 25 cm, the ribbon material is wound onto a stainless steel mandrel with a diameter of 15 mm and heat-treated in air at various temperatures for one hour.

After the heat treatment, the diameter of the spring material tempered by relaxation of the strip material is measured and the complete amorphousness is checked by a buckling test. Table 3 shows the results.

It can be seen that temperatures in the range of 150-350° C. are particularly suitable for impressing a spiral shape on the spring ribbon by means of temperature-induced relaxation processes. At temperatures below 150°C, the temperature is not sufficient to activate the diffusion and thus set a spiral shape. At temperatures above 350°C, individual surface crystallites begin to crystallize, which means that the strip breaks brittle in the buckling test. Heat treatment temperature [°C] Initial diameter (= mandrel diameter) [mm] 100 15 150 15 200 15 250 15 300 15 350 15 400 15 500 15 Table 3: Heat treatment temperature of an amorphous strip material with the composition Ni ₆₇ Cr _6.5 Fe _2.5 Si ₈ B ₁₆ (in at.%) for setting the spiral shape typical for spring applications Diameter after heat treatment (relaxed condition) [mm] Buckling test (+ = elastic, - = brittle) Not measurable + 35 + 28 + 20 + 18 + 17 + 17 - 17 -

The present invention thus provides winding springs made from an amorphous metal alloy and a corresponding method for their production.

The starting point for winding springs according to the present invention is an amorphous strip material, which is initially preferably produced using a melt spinning process as a continuous strip or film with a thickness of typically 50-200 μm.

After the amorphous wide strip has been preferably cut to the desired width of the spring element or edge-ground, the strip material is fixed by winding, for example onto a mandrel, and heat-treated at a temperature below the crystallization temperature of the amorphous starting material between 150-400°C to achieve the temperature required for mainsprings shape (spiral, half-inverted spiral, inverted spiral or S-shape).

The above-mentioned alloy compositions are used as the material for amorphous mainsprings according to the invention, since they have high mechanical strength and a relatively low modulus of elasticity and thus enable the mainspring to have a high energy storage capacity. In addition, the alloys mentioned are resistant to oxidation and corrosion and also non-magnetic, ie non-ferromagnetic, at the typical operating temperatures of the mainspring.

Furthermore, they can be produced in a strip thickness between 50-200 μm as an amorphous strip material, for example by means of melt spinning processes, which is also of particular importance for the present invention. These amorphous alloys also have a sufficiently high crystallization temperature T _x in the range of 400-600 ° C, whereby the inventive shaping of the amorphous springs at a temperature between preferably 150 ° C and less than 400 ° C is possible without the mechanical Properties of the amorphous strip material undesired crystallization occurs.

The mainspring has an amorphous alloy whose composition advantageously enables large-scale production and/or processing in air, i.e. in particular under normal atmospheric conditions.

Reference List

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Claims (31)

A spring for a mechanical timepiece, the spring comprising an amorphous alloy having a composition consisting of Ni _a CO _b Fe _c Cr _d B _e Si _f C _g P _h Mo _i Nb _k V _l Ta _m W _n , with 0 atomic % ≤ c ≤ 25.0 atomic %, 2.0 atomic % ≤ d ≤ 21.0 atomic %, 1.0 atomic % ≤ e ≤ 20.0 atomic %, 0 atomic % %≦f≦20.0 at%, 0 at%≦g≦20.0 at%, 0 at%≦h≦20.0 at%, 0 at%≦i≦5.0 at% -%, 0 at% S k ≤ 5.0 at%, 0 at% ≤ l ≤ 5.0 at%, 0 at% ≤ m ≤ 5.0 at%, 0 at% ≤ n ≤ 5.0 at%; incidental impurities ≤ 1.0% by weight; Balance Ni and/or Co, where 15.0 at% < e + f + g + h < (0.033 x ² - 1.2 x + 32) at%, where x is the content of Cr in at -% is. feather after claim 1 , where 0 at% ≤ c ≤ 5.0 at%, 4.0 at% ≤ d S 12.0 at%, 5.0 at% ≤ e ≤ 18.0 at%, 0 at -% ≤ f ≤ 10.0 at%, 0 at% ≤ i ≤ 5.0 at%, 0 at% ≤ k ≤ 5.0 at%; b = g = h = l = m = n = 0 atomic %. feather after claim 2 , where 2.0 at% ≤ c ≤ 3.0 at%, 6.0 at% ≤ d ≤ 10.0 at%, 7.0 at% ≤ e ≤ 16.0 at%, 2.0 at%≦f≦8.0 at%, 2.0 at%≦i≦3.0 at%, 2.0 at%≦k≦3.0 at%. feather after claim 2 , wherein the amorphous alloy has a composition selected from the group consisting of Ni ₆₇ Cr ₆ , ₅ Fe ₂ , ₅ Si ₈ B ₁₆ , Ni _71.1 Cr ₆ , ₆ Si ₇ , ₈ B ₁₄ , ₅ , Ni ₇₀ Cr ₈ Si ₈ B ₁₄ and Ni ₇₀ Cr ₈ Si ₇ B ₁₄ Mo ₁ . A spring for a mechanical timepiece, the spring comprising an amorphous alloy having a composition consisting of Ni _a Cr _b Si _c P _d B _e Fe _f Mo _g Nb _h , with 4.0 at% ≤ b ≤ 21.0 at%, 0 at% ≤ c ≤ 10.0 at%, 5.0 at% ≤ d ≤ 18.0 at%, 1.0 atomic % ≤ e ≤ 5.0 atomic %, 0 atomic % ≤ f ≤ 5.0 atomic %, 0 atomic % ≤ g ≤ 5.0 atomic %, 0 atomic % ≤ h ≤ 5, 0 atomic %; incidental impurities ≤ 1.0% by weight; Rest Ni exists. feather after claim 5 , where 6.0 at% ≤ b ≤ 20.0 at%, 1.0 at% ≤ c ≤ 8.0 at%, 7.0 at% ≤ d ≤ 16.0 at%, 2.0 at% ≤ e ≤ 4.0 at%, 2.0 at% ≤ f ≤ 3.0 at%, 2.0 at% ≤ g ≤ 3.0 at% and 2, 0 at% ≤ h ≤ 3.0 at%. feather after claim 5 , wherein the amorphous alloy has a composition selected from the group consisting of Ni ₆₁ Cr ₁₈ Si ₄ P ₁₃ B ₄ , Ni ₆₅ Cr ₁₇ Si _6.5 P ₉ B _2.5 , Ni ₆₃ Cr ₁₈ Si ₂ P ₁₃ B ₄ and Ni _62.5 Cr ₂₀ Si ₁ P ₁₄ B _2.5 . A spring as claimed in any preceding claim, wherein the spring has a thickness d where 50 µm ≤ d ≤ 200 µm. A spring according to any one of the preceding claims, wherein the spring is S-shaped and/or helical in the relaxed state. A spring as claimed in any one of the preceding claims, wherein the amorphous alloy has a crystallisation temperature T _x where T _x > 400°C. feather after claim 10 , where T _x > 450°C. A spring according to any one of the preceding claims, wherein the amorphous alloy has a Vickers hardness HV 0.5 of 775 to 990. Spring according to one of the preceding claims, wherein the spring is designed as a mainspring. Spring according to one of the preceding claims, wherein the spring is designed as a winding spring. Mechanical clockwork comprising a spring according to one of the preceding claims. Clock having a mechanical clockwork claim 15 . Method for producing a spring according to one of Claims 1 until 14 , the method comprising the steps of: - melting the alloy, - forming an amorphous ribbon from the molten alloy, - winding the amorphous ribbon on a first fixture in a first winding direction, - heat treating the wound ribbon. procedure after Claim 17 , wherein the heat treatment of the coiled strip is carried out in air. procedure after Claim 17 or Claim 18 , whereby the melting of the alloy takes place in air. Procedure according to one of claims 17 until 19 , wherein the forming of the amorphous ribbon from the molten alloy occurs in air. Procedure according to one of claims 17 until 20 , wherein the heat treatment of the coiled strip is carried out at a temperature T, where 0.3 · T _x ≤ T ≤ 0.7 · T _x , where T _x is the crystallization temperature of the amorphous alloy. Procedure according to one of claims 17 until 21 , wherein the heat treatment of the coiled tape is performed at a temperature T, where 150°C ≤ T ≤ 350°C. Procedure according to one of claims 17 until 22 wherein the amorphous ribbon is further wound on a second fixture in a second winding direction, the second winding direction being opposite to the first winding direction. Procedure according to one of claims 17 until 23 wherein the forming of the amorphous ribbon from the molten alloy is accomplished by a rapid solidification process. procedure after Claim 24 wherein the amorphous ribbon is formed from the molten alloy by a melt spinning process. Procedure according to one of claims 17 until 25 , wherein the forming of the amorphous ribbon from the molten alloy is made into an amorphous ribbon having a thickness d, where 50 µm ≤ d ≤ 200 µm. Procedure according to one of claims 17 until 26 wherein after forming the amorphous ribbon from the molten alloy, a width of the ribbon is reduced. procedure after Claim 27 , wherein the width reduction of the amorphous ribbon is performed by cutting with circular shears. procedure after Claim 27 or claim 28 , wherein reducing the width of the amorphous ribbon is done by wire EDM. Use of an amorphous alloy in a spring for a mechanical timepiece having a composition consisting of Ni _a CO _b Fe _c Cr _d B _e Si _f C _g P _h MO _i Nb _k V _l Ta _m W _n , with 0 atomic % ≤ c ≤ 25.0 atomic %, 2.0 atomic % ≤ d ≤ 21.0 atomic %, 1.0 at% ≤ e ≤ 20.0 at%, 0 at% ≤ f ≤ 20.0 at%, 0 at% ≤ g ≤ 20.0 at%, 0 at% ≤ h ≤ 20.0 at%, 0 at% ≤ i ≤ 5.0 at%, 0 at% ≤ k ≤ 5.0 at%, 0 at% ≤ l ≤ 5.0 at%, 0 at%≦m≦5.0 at%, 0 at%≦n≦5.0 at%; incidental impurities ≤ 1.0% by weight; Balance Ni and/or Co, where 15.0 at% < e + f + g + h < (0.033 x ² - 1.2 x + 32) at%, where x is the content of Cr in at -% is. Use of an amorphous alloy in a spring for a mechanical timepiece having a composition consisting of Ni _a Cr _b Si _c P _d B _e Fe _f Mo _g Nb _h , with 4.0 ≤ b ≤ 21.0, 0 ≤ c ≤ 10.0, 5.0 ≤ d ≤ 18.0, 1.0 ≤ e ≤ 5.0, 0 S f ≤ 5.0, 0 ≤ g ≤ 5.0, 0 ≤ h ≤ 5.0; incidental impurities ≤ 1.0% by weight; Rest Ni exists.

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