HK1209461B

HK1209461B - Zirconium-based and beryllium free bulk amorphous alloy

Info

Publication number: HK1209461B
Application number: HK15110063.4A
Authority: HK
Inventors: Alban Dubach; Yves Winkler; Tommy Carozzani
Original assignee: The Swatch Group Research And Development Ltd.
Priority date: 2013-12-06
Filing date: 2015-10-14
Publication date: 2018-03-02

Description

Bulk amorphous alloys based on zirconium and free of beryllium

Technical Field

The present invention relates to bulk amorphous alloys.

The invention further relates to a timing element made of the alloy.

The invention relates to the field of timepieces and gems, in particular to a watch case, a case middle (case midles), a main board, a meter front cover, a button, a crown, a buckle, a bracelet, a ring, an earring and the like.

Background

Amorphous alloys are increasingly used in the field of timepieces and gems, in particular in the case of watch cases, case middles, main boards, bezel covers, buttons, crown caps, clasps, bracelets, rings, earrings, etc.

Elements intended to come into contact with the skin of the user for external applications must comply with specific limits, in particular due to the toxic or allergic effects of some metals, in particular beryllium and nickel. Despite the specific inherent properties of these metals, there are still attempts to market alloys containing little or no beryllium or nickel, at least for components that are prone to contact with the user's skin.

Bulk amorphous alloys based on zirconium have been known since the 90 s. The following publications refer to these alloys:

[1] zhang et Al, amorphous Zr-Al-TM (TM ═ Co, Ni, Cu) alloys with a significantly supercooled liquid region of over 100K, Materials Transactions, JIM, volume 32, No.11(1991), page 1005-1010.

[2] Lin et Al, influence of oxygen impurities on crystallization of Zr-Ti-Cu-Ni-Al alloy forming supercooled bulk glass, Materials transformations, JIM, volume 38, No.5(1997) page 473 477.

[3] US patent No 6592689.

[4] Inoue et Al, formation, thermal stability and mechanical properties of bulk glass alloys having a diameter of 20mm in the Zr- (Ti, Nb) -Al-Ni-Cu system, Materials transformations, JIM, Vol.50, No.2(2009), p.388-394.

[5] Zhang et Al, ternary Cu-Zr-Al and quaternary Cu-Zr-Al-Ag bulk metallic glasses, Materials transformations, volume 48, No.7(2007) page 1626-.

[6] Inoue et Al, formation of icosahedral quasicrystal phases in the Zr-Al-Ni-Cu-M (M ═ Ag, Pd, Au or Pt) system, Materials Transactions, JIM, Vol.40, No.10(1999) p.1181-1184.

[7] Inoue et Al, influence of additional elements on the glass transition behavior and glass formation tendency of Zr-Al-Cu-Ni alloys, Materials transformations, JIM, volume 36, No.12(1995), page 1420-.

Amorphous alloys with optimal glass forming ability, hereinafter referred to as "GFA", were found in the following system:

-Zr-Ti-Cu-Ni-Be (e.g. LM1b, Zr44Ti11Cu9.8Ni10.2Be25), and

-Zr-Cu-Ni-Al。

because beryllium is toxic, alloys containing beryllium cannot be used in applications involving contact with skin, such as external watch components and the like. However, amorphous alloys based on zirconium and free of beryllium generally exhibit lower critical diameters than alloys containing beryllium, which is disadvantageous for producing large parts. In the Zr-Cu-Ni-Al system, at the critical diameter (D)_c) And at the crystallization temperature T_xAnd glass transition temperature T_g(supercooled liquid region) difference Δ T between_xThe most preferred composition in the aspect is alloy Zr₆₅Cu_17.5Ni₁₀Al_7.5[1]。

Modifications are also known in which the GFA is modified by the addition of titanium and/or niobium:

-Zr_52.5Cu_17.9Ni_14.6Al₁₀Ti₅(Vit105)[2]，

-Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅(Vit106) and Zr_58.5Cu_15.6Ni_12.8Al_10.3Nb_2.8(Vit106a)[3]，

-Zr₆₁Cu_17.5Ni₁₀Al_7.5Ti₂Nb₂[4]。

Generally, the addition of titanium and/or niobium increases the critical diameter of the alloy, but this modification significantly reduces the gradient Δ T_xThe working range for any hot deformation of such an alloy is reduced. In addition, since niobium has a very high melting temperature (2468 ℃), niobium does not easily melt, which complicates the production of a homogeneous alloy.

It is known that the addition of silver to ternary Zr-Cr-Al alloys increases the critical diameter, in particular for improving the composition Zr₄₆Cu₄₆Al₈For example Zr₄₂Cu₄₂Al₈Ag₈[5]。

However, due to the high content of copper and the absence of nickel, these alloys are not very corrosion resistant and even tend to discolor (and/or blacken) over time at ambient temperatures.

In addition, it is known that addition of more than 5% of silver, gold, palladium or platinum to Zr-Cu-Ni-Al amorphous alloys can be promoted by adding more than 5% of silver, gold, palladium or platinum at T_gAnd T_xWith intermediate heat treatment to devitrify these alloys [ 6)]。

In 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 Zr — Cu — Ni — Al-M alloy was examined.

The results demonstrate that titanium, niobium and palladium alone increase the critical diameter of the alloy, but also significantly reduce the gradient Δ Τ_x. No mention is made about the specific effect of adding silver to the alloy.

The following documents include zirconium-based alloys with silver or gold.

U.S. patent nos. 5980652 and 5803996 describe alloys of the following types:

Zr_bal-(Ti,Hf,Al,Ga)_5-20-(Fe,Co,Ni,Cu)_20-40-(Pd,Pt,Au,Ag)_0-10

more particularly alloys with palladium and/or platinum, wherein the individual examples mention the addition of 1% gold or 1% silver, but the effect of such addition on increasing the critical diameter was not evaluated.

EP patent No 0905268 describes an alloy of the following type:

(Zr,Hf)_25-85-(Ni,Cu,Fe,Co,Mn)_5-70-Al_>0-35-T_>0-15

where T is an element having a negative enthalpy of mixing with one of the other elements and is selected from the group consisting of T ═ Ru, Os, Rh, Ir, Pd, Pt, V, Nb, Ta, Cr, Mo, W, Au, Ga, Ge, Re, Si, Sn or Ti. This document only gives examples using palladium. No evidence of the element T for D_cAnd Δ T_xAny positive effect of (a).

EP specialNo 0905269 describes a method for making a multi-phase alloy (14-23% crystalline phase in an amorphous matrix) in which Zr is added_25-85-(Ni,Cu)_5-70-Al_>0-35-Ag_>0-15And (4) performing heat treatment.

CN patent No 101314838 describes the following types of alloys:

Zr_41-63-Cu_18-46-Ni_1.5-12.5-Al_4-15-Ag_1.5-26

in summary, the effects of adding low concentrations of silver or gold to these amorphous alloys are not known and have not been specifically studied in the literature.

Disclosure of Invention

The aim of the invention is to increase the critical diameter of amorphous alloys based on zirconium and free of beryllium, while maintaining high Δ Tx values.

The invention relates to a solid amorphous alloy based on zirconium and/or hafnium and free of beryllium, to which silver and/or gold and/or platinum are added in order to increase the critical diameter thereof.

To this end, the invention relates to a bulk amorphous alloy, characterized in that it is beryllium-free and contains, as atomic percentage values:

-a matrix consisting of zirconium and/or hafnium, wherein the total amount of zirconium and hafnium has a minimum value of 50% and a maximum value of 63%;

-a first additional metal, wherein the at least one first additional metal or the sum of the plurality of first additional metals comprised (including the minimum and maximum values) is between a minimum value of 1.5% and a maximum value of 4.5%, said at least one first additional metal being selected from a first group comprising titanium, niobium and tantalum, wherein the niobium content is less than or equal to 2.5%;

-a second additional metal, wherein the at least one second additional metal or the sum of the plurality of second additional metals comprised (including the minimum and maximum) is between 0.5% minimum and 4.5% maximum, the at least one second additional metal being selected from a second group comprising silver, gold and platinum;

-a third additional metal, wherein the at least one third additional metal or the sum of the plurality of third additional metals comprised (including the minimum and maximum) is between a minimum of 8.5% and a maximum of 17.5%, the at least one third additional metal being selected from a third group comprising nickel, cobalt, manganese and iron;

minimum 9% and maximum 13% of aluminium;

copper and unavoidable impurities, the complement to 100%, but less than or equal to 18%.

According to a particular aspect of the invention, the at least one first additional metal or the sum of the plurality of first additional metals comprised (including the minimum and maximum values) is between a minimum of 2.5% and a maximum of 4.5%.

The invention further relates to a timing element or a jewel element made of an alloy of said type.

Drawings

Further features and advantages of the invention will be described in detail below with reference to the drawings, in which:

FIG. 1 shows a schematic representation of the detection of the critical diameter in a conical sample.

Figure 2 shows a schematic view of a timing element made of the alloy according to the invention.

The specific implementation mode is as follows:

the invention relates to the field of timepieces and gems, in particular to a watch case, a case middle part, a main board, a meter front cover, a button, a crown, a buckle ring, a bracelet, a ring, an earring and the like.

The object of the present invention is to produce amorphous beryllium-free steels with properties similar to those of amorphous alloys containing beryllium. Hereinafter, an alloy containing no beryllium will be referred to as "beryllium-free alloy", and an alloy containing less than 0.5 atomic% nickel will be referred to as "nickel-free alloy".

"beryllium-free" means that the content of beryllium is preferably 0, or very low, as impurities, preferably less than or equal to 0.1%.

It is therefore sought to prepare alloys containing alternative elements to beryllium and having a high critical diameter D_cAnd a gradient Δ Tx value.

The invention further relates to a zirconium-based bulk amorphous alloy which is free of beryllium and to which silver and/or gold and/or platinum are additionally added in order to increase the critical diameter D_c。

More particularly, the invention relates to a bulk amorphous alloy characterized in that it is beryllium-free and comprises, as atomic percentage values:

minimum 9% and maximum 13% of aluminium;

More particularly, wherein the at least one first additional metal or the sum of the plurality of first additional metals contained (including the minimum and maximum values) is between a minimum of 2.5% and a maximum of 4.5%, the at least one first additional metal is selected from the first group comprising titanium, niobium and tantalum, wherein the niobium content is less than or equal to 2.5%.

Although a variety of amorphous compositions based on zirconium are known, amorphous alloys having the composition of the present invention provide new and quite surprising results, since especially 2% of the additive is sufficient to significantly increase the critical diameter.

The effect of 0.5-4.5% of a second additional metal selected from a second group comprising silver, gold and platinum is evident: the addition of one or another or several other of these elements to the alloy increases the critical diameter without decreasing the gradient Δ Tx compared to an alloy without these additives.

The transformation zone, which shows a negative gradient of the critical diameter, is initiated at about 4.5% and after 5%, the critical diameter is significantly reduced, compared to the optimum amount comprised (including the minimum and maximum values) between the lower limit of 0.5% (at which point the effect of adding the second additional metal is initially observed) and the upper limit of 4.5%.

The range from 1.0 to 4.0% is advantageous, very good results being obtained in the range from 1.5 to 3.8%.

More particularly, the gold content is 1.5-2.5%.

More particularly, the platinum content is 1.5-2.5%.

More particularly, the silver content is 1.0-3.8%.

In one embodiment, the total amount of zirconium and hafnium in the matrix is limited to 60%.

In one embodiment, the alloy of the present invention is free of titanium.

In one embodiment, the alloy of the present invention is free of niobium.

In one embodiment, the alloy of the present invention is free of titanium and niobium.

Palladium did not prove to have any beneficial effect during the development of the present invention, unlike the metals of the second group, i.e. silver, gold and platinum. Palladium may also be included in the second group, but its content should preferably be kept very low, in particular less than or equal to 1.0%.

Non-limiting exemplary embodiments are described below: approximately 70g of the alloy mass was prepared in an arc furnace using pure elements (greater than 99.95% purity). The pre-alloy thus obtained was then remelted in a centrifugal casting machine and cast in a conical shaped copper mold (maximum thickness 11mm, width 20mm, opening angle 6.3 °).

DSC measurements were made of the glass transition temperature and crystallization temperature of the samples taken from the end of each cone. Performing metallographic cutting in the middle of each taper length direction to detect the critical diameter D_cWherein D_cIs the cone thickness at the beginning of the crystallization zone, as shown in fig. 1.

The following table summarizes the experiments performed (the compositions indicated in italics are compositions known in the literature). It can be seen that the critical diameter D can be significantly increased compared to a base alloy without silver, gold or palladium additives, using suitable amounts of these additives_c*. In addition, these additives do not reduce the gradient Δ T_x。

More particularly, the following alloys give particularly satisfactory results:

Zr62Cu15Ag3Ni10Al10,

Zr58.5Cu15.6Ni12.8Al10.3Ag2.8,

Zr57.9Cu15.44Ni12.67Al10.9Ag3.8

Zr52.5Ti2.5Cu15.9Ag2Ni14.6Al12.5

Zr52.5Ti2.5Cu15.9Au2Ni14.6Al12.5

Zr52.5Ti2.5Cu15.9Pt2Ni14.6Al12.5

Zr52.5Ti2.5Cu16.9Ag1Ni14.6Al12.5

Zr52.5Ti2.5Cu14.9Ag3Ni14.6Al12.5

Zr52.5Nb2.5Cu15.9Ag2Ni14.6Al12.5。

a first advantageous embodiment relates to a total content of zirconium and hafnium greater than 57.0%, wherein the total content of the first additional metal is less than or equal to 0.5%.

A second advantageous embodiment relates to a total content of zirconium and hafnium which is less than or equal to 53.0%, wherein the total content of the first additional metal is between 1.5 and 3.0%, more particularly between 2.0 and 3.0%. In practice, the alloy with the largest critical diameter contains about 2.5% titanium or niobium.

In another embodiment of the invention, other elements are introduced, such as iron and manganese.

The search for a balance may identify an optimum composition, particularly with the desired silver content, which is advantageous because silver is less costly than gold and platinum, but provides the desired effect.

In order to optimize the alloy, several rules were determined during the experiment: particularly advantageous results are obtained as follows:

-ratio of zirconium content to copper content: Zr/Cu is 3.0 to 5.0;

-ratio of zirconium content to total copper and nickel content: Zr/(Cu + Ni) is 1.5-3.0;

-ratio of the total content of zirconium, hafnium, titanium, niobium and tantalum to the total content of copper and nickel: (Zr, Hf, Ti, Nb, Ta)/(Cu + Ni) is 1.5 to 3.0;

-the at least one first additional metal or the sum of the plurality of first additional metals (including the minimum and maximum) is between a minimum of 2.5% and a maximum of 4.5%;

-the aluminium content is greater than 10.0%.

The introduction of nickel into alloys has created the problem of causing allergic effects in the nickel itself or in alloy compositions containing other metals. However, the presence of nickel in amorphous alloys is advantageous for obtaining amorphous alloys based on zirconium with high critical diameter and excellent corrosion resistance. Similarly, stainless steel also contains a high nickel content and is widely used in the gemstone and horological arts.

An important limitation to observe is that the resulting alloy is able to meet the nickel release test in accordance with EN 1811.

In one embodiment of the invention, the alloy contains less than 0.5% nickel.

It should be understood that nickel cannot simply be replaced by other metals to achieve the same characteristics. Elements with approximate atomic radii are iron, cobalt, palladium, manganese and chromium. Therefore, this means reconsidering the overall composition of the amorphous alloy.

The invention therefore relates to a second bulk amorphous alloy, characterized in that it is beryllium-free and comprises, as atomic percentage values:

-a first additional metal, wherein the at least one first additional metal or the sum of the plurality of first additional metals comprised (including the minimum and maximum values) is between a minimum of 0% and a maximum of 4.5%, said at least one first additional metal being selected from a first group comprising titanium, niobium and tantalum, wherein the niobium content is less than or equal to 2.5%;

-a second additional metal, wherein the at least one second additional metal or the sum of the plurality of second additional metals comprised (including the minimum and maximum) is between 0.5% minimum and 4.5% maximum, the at least one second additional metal being selected from a second group comprising silver, gold, palladium and platinum;

minimum 9% and maximum 13% of aluminium;

The invention also relates to a timing element or a jewel element, or a timepiece or a jewel, in particular a watch or a bracelet, made of the alloy according to the invention.

Claims

1. A bulk amorphous alloy, characterized in that it is beryllium-free and contains, as atomic percentage values:

-a matrix consisting of zirconium and/or hafnium, wherein the total amount of zirconium and hafnium has a minimum value of 50% and less than or equal to 53.0%;

-a first additional metal, wherein the at least one first additional metal or the sum of said plurality of first additional metals comprised is 2.0-3.0%, said at least one first additional metal being selected from a first group comprising titanium, niobium and tantalum, wherein the niobium content is less than or equal to 2.5%;

-a second additional metal, wherein the at least one second additional metal or the sum of the plurality of second additional metals comprised is between a minimum of 0.5% and a maximum of 4.5%, the at least one second additional metal being selected from a second group comprising silver, gold and platinum;

-a third additional metal, wherein the at least one third additional metal or the sum of the plurality of third additional metals comprised is between a minimum of 8.5% and a maximum of 17.5%, the at least one third additional metal being selected from a third group comprising nickel, cobalt, manganese and iron;

minimum 9% and maximum 13% of aluminium;

copper and unavoidable impurities, the complement to 100%, but less than or equal to 18%,

and is characterized in that: the atomic percent value of the gold content is 1.5-2.5%, or the atomic percent value of the platinum content is 1.5-2.5%, or the atomic percent value of the silver content is 1.0-3.8%.

2. Alloy according to claim 1, characterized in that said at least one second additional metal or the sum of said plurality of second additional metals is comprised between a minimum of 1.0% and a maximum of 4.0%.

3. Alloy according to claim 2, characterized in that the sum of said at least one or more second additional metals contained is between a minimum of 1.5% and a maximum of 3.8%.

4. Alloy according to claim 1, characterized in that the aluminium content is greater than 10.0% and less than or equal to 13%.

5. Alloy according to claim 1, characterized in that the ratio of the zirconium content to the copper content Zr/Cu is between 3.0 and 5.0.

6. Alloy according to claim 1, characterized in that the ratio of the zirconium content to the total content of copper and nickel Zr/(Cu + Ni) is between 1.5 and 3.0.

7. Alloy according to claim 1, characterized in that the ratio of the sum of the atomic percentages of zirconium, hafnium, titanium, niobium and tantalum to the sum of the atomic percentages of copper and nickel (Zr + Hf + Ti + Nb + Ta)/(Cu + Ni) is between 1.5 and 3.0.

8. An alloy according to claim 1, characterized in that the alloy contains no titanium.

9. Alloy according to claim 1, characterized in that the alloy is free of niobium.

10. The alloy according to claim 1, characterized in that the alloy is free of titanium and niobium.

11. Alloy according to claim 1, characterized in that the alloy contains less than 0.5% nickel as atomic percentage.

12. A bulk amorphous alloy, characterized in that it is beryllium-free and contains, as atomic percentage values:

-a second additional metal, wherein the at least one second additional metal or the sum of the plurality of second additional metals comprised is between a minimum of 0.5% and a maximum of 4.5%, the at least one second additional metal being selected from a second group comprising silver, gold, palladium and platinum;

minimum 9% and maximum 13% of aluminium;

13. Element for a timepiece or for a gemstone, made of an amorphous alloy according to claim 1 or 12.