Light precious alloy of gold and titanium and components for timepieces or jewellery made from such a light precious alloy of gold and titanium

Abstract

Light, precious gold-titanium based alloy containing, by mass, at least 750 of gold, characterized in that said alloy has the following composition formula:
Ti.sub.aAu.sub.bM.sub.cT.sub.d
where a, b, c, d are atomic proportions such that:
a+b+c+d=1,
0.45a0.55; 0.41b0.495; 0.025c0.13; 0.001d0.025,
where M represents one or more elements taken from among a first group including Nb, V, Pd, Pt, Fe,
and where T represents a maximum of two elements taken from among a second group including Nb, V, Pd, Pt, Fe, Mo, Ta, W, Co, Ni, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, B, Si, Ge, Sn, Sb, In, with the exception of said metals M comprised in said alloy. Component for timepiece or for jewellery made from such a light, precious gold-titanium based alloy.

Claims

1. A light, precious gold-titanium based alloy comprising, by mass, from 750 to 780 of gold, wherein said alloy has the following composition formula:
Ti.sub.aAu.sub.bM.sub.cT.sub.d where a b, c, d are atomic proportions such that:
a+b+c+d=1, 0.45a0.55; 0.41b0.495; 0.025c0.13; 0.001d0.025, wherein M represents at least one element selected from the group consisting of Nb, V, Pd, Pt, and Fe, and T represents boron and optionally an additional element, and wherein the additional element is selected from the group consisting of Nb, V, Pd, Pt, Fe, Mo, Ta, W, Co, Ni, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, Si, Ge, Sn, Sb, and In, M and T are different elements, and the alloy comprises the boron as T or as a part of T in an atomic content of from 0.03% to 0.3%.

2. The alloy according to claim 1, wherein the additional element is selected from the group consisting of Nb, V, Pd, Pt, Fe, Mo, Ta, W, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, Si, Ge, Sn, and In.

3. The alloy according to claim 1, wherein 0.48a0.52; 0.42b0.48; 0.025c0.10; 0.001d0.025.

4. The alloy according to claim 3, wherein 0.49a0.51; 0.42b0.48; 0.025c0.09; 0.001d0.025.

5. The alloy according to claim 4, wherein 0.50a0.51; 0.42b0.47; 0.025c0.08; 0.001d0.025.

6. The alloy according to claim 5, wherein the additional element is selected from the group consisting of Nb, V, Pd, Pt, Fe, Ru, Rh, Ir, and Cr.

7. The alloy according to claim 6, wherein M represents at least one element selected from the group consisting of Nb, Pd, Pt, and Fe.

8. The alloy according to claim 1, wherein, when the atomic proportion of the boron is from 0.03% to 0.10%, the additional element is selected from the group consisting of Nb, V, Pd, Pt, Fe, Ru, Rh, Ir, and Cr.

9. The alloy according to claim 1, wherein M is iron.

10. The alloy according to claim 1, wherein M is niobium.

11. The alloy according to claim 1, wherein M is platinum.

12. The alloy according to claim 1, wherein M is palladium.

13. The alloy according to claim 1, wherein the mass content of the gold in said alloy is from 750 to 760.

14. A timepiece or jewelry component, comprising: the light precious gold-titanium based alloy according to claim 1.

Description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(1) All of the concentrations expressed in the present description are atomic proportions, unless otherwise specified, in particular as regards gold.

(2) The invention concerns a gold-titanium dominant alloy in the following formulation:
Ti.sub.aAu.sub.bM.sub.cT.sub.d
where a, b, c, d are atomic proportions such that:
a+b+c+d=1,
0.45a0.55;
0.41b0.495;
0.025c0.13;
0.001d0.025,
where M represents one or more elements taken from among a first group including Nb, V, Pd, Pt, Fe,
where the gold mass content is greater than or equal to 750,
and where T represents a maximum of two elements taken from among a second group including Nb, V, Pd, Pt, Fe, Mo, Ta, W, Co, Ni, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, B, Si, Ge, Sn, Sb, In, with the exception of the metals M comprised in this alloy.

(3) Parameter a defines the fraction of titanium.

(4) Parameter b defines the fraction of gold.

(5) Parameter c defines the total fraction of elements M.

(6) Parameter d defines the total fraction of elements T.

(7) The alloy includes 750 by mass of gold. This mass percentage of the alloy is naturally not inconsistent with the atomic proportions of the alloying elements, it is an additional condition related to fineness grading, and which is not at all incompatible with the alloy compositions described in the present invention.

(8) More particularly, for applications relating to components that might come into contact with a user's skin, nickel is excluded from the alloy, and the formulation is restricted as regards T, which represents a maximum of two elements taken from among a third group corresponding to second group from which nickel is removed, and including: Nb, V, Mo, Ta, W, Fe, Co, Ru, Rh, Ir, Pd, Pt, Cr, Mn, Cu, Zn, Ag, Al, B, Si, Ge, Sn, Sb, In, with the exception of the metals M comprised in this alloy.

(9) The same alternative concerns the whole of the present description for any alloy likely to be used in a similar application.

(10) More particularly, the fraction of titanium a. of gold b and of element M c of the formulation is restricted in the form:
Ti.sub.aAu.sub.bM.sub.cT.sub.d
with 0.48a0.52; 0.42b0.48; 0.025c0.10; 0.001d0.025.

(11) More particularly, the fraction of titanium a and of element M c of the formulation is restricted in the form:
Ti.sub.aAu.sub.bM.sub.cT.sub.d
with 0.49a0.51; 0.42b0.48; 0.025c0.09; 0.001d0.025.

(12) More particularly, the fraction of titanium a. of gold b and of element M c of the formulation is restricted in the form:
Ti.sub.aAu.sub.bM.sub.cT.sub.d
with 0.50a0.51; 0.42b0.47; 0.025c0.08; 0.001d0.025.

(13) The range of 0.50-0.51 for the atomic fraction of titanium corresponds to the range of stability of the equiatomic intermetallic phase TiAu at ambient temperature in the binary TiAu system.

(14) More particularly still, T represents a maximum of two elements taken from among a fourth group that is more restricted than the third group and includes: Nb, V, Fe, Ru, Rh, Ir, Pd, Pt, Cr, Cu, Ag, B, with the exception of the metals M comprised in the alloy.

(15) More particularly still, M represents one or more elements belonging to a fifth group corresponding to the first group from which vanadium has been removed and including: Nb, Pd, Pt, Fe.

(16) More particularly still, in order to use boron as grain refiner, T represents, on the one hand, boron in a content comprised between 0.03% and 0.3%, and, on the other hand, at least in the case where the minimum value d of 0.1% is not attained, only one element from a sixth group including: Nb, V, Fe, Ru, Rh, Ir, Pd, Pt, Cr, Cu, Ag, in sufficient quantity such that value d, which is the sum of the atomic fraction of boron and that of said element from said sixth group, is between 0.001 and 0.025.

(17) The following compositions provide the formula for particularly promising alloys, combining ease of implementation, reduced density, attractive appearance and reduced surplus gold content, which is essential for watchmaking and jewellery applications.

(18) The formulation is of the type:
Ti.sub.aAu.sub.bM.sub.bT.sub.d
with 0.50a0.51; 0.42b0.47; 0.025c0.08; 0.001d0.025,
where M represents only one element from the fifth group including Nb, Pd, Pt, Fe, and where T represents boron in a content comprised between 0.03% and 0.3% and, at least in the case where the minimum atomic value d of 0.1% is not attained, only one element from the sixth group including: Nb, V, Fe, Ru, Rh, Ir, Pd, Pt, Cr, Cu, Ag, in sufficient quantity such that value d, which is the sum of the atomic fraction of boron and that of said element from the sixth group, is between 0.001 and 0.025.

(19) More particularly, M is iron.

(20) More particularly, M is niobium.

(21) More particularly, M is platinum.

(22) More particularly, M is palladium.

(23) More particularly, the mass content of gold in the alloy is less than 780.

(24) More particularly still, the mass content of gold in the alloy is less than 760.

(25) Examples of atomic compositions wherein a=0.50 and d=0.001 are given below:

(26) TABLE-US-00001 Ti.sub.0.50Au.sub.0.427Fe.sub.0.072B.sub.0.001 Fineness of Au: 750.5 a = 0.50; b = 0.427; c = 0.072; d = 0.001 Ti.sub.0.50Au.sub.0.444Nb.sub.0.055B.sub.0.001 Fineness of Au: 750.6 a = 0.50; b = 0.444; c = 0.055; d = 0.001 Ti.sub.0.50Au.sub.0.466Pt.sub.0.033B.sub.0.001 Fineness of Au: 751.3 a = 0.50; b = 0.466; c = 0.033; d = 0.001 Ti.sub.0.50Au.sub.0.448Pd.sub.0.051B.sub.0.001 Fineness of Au: 750.3 a = 0.50; b = 0.448; c = 0.051; d = 0.001

(27) Other examples of atomic compositions wherein a=0.505, and d represents two elements are set out below:

(28) TABLE-US-00002 Ti.sub.0.505Au.sub.0.4295Fe.sub.0.050Cr.sub.0.015B.sub.0.0005 Fineness of Au: 753 a = 0.505; b = 0.4295; c = 0.05; d = 0.0155 Ti.sub.0.505Au.sub.0.4385Nb.sub.0.041Cr.sub.0.015B.sub.0.0005 Fineness of Au: 750.2 a = 0.505; b = 0.4385; c = 0.041; d = 0.0155 Ti.sub.0.505Au.sub.0.448Pd.sub.0.0365Rh.sub.0.01B.sub.0.0005 Fineness of Au: 752.1 a = 0.505; b = 0.448; c = 0.0365; d = 0.0105 Ti.sub.0.505Au.sub.0.463Pt.sub.0.031Ir.sub.0.0005B.sub.0.0005 Fineness of Au: 750.5 a = 0.505; b = 0.463; c = 0.031; d = 0.001.

(29) In a variant of the invention, several % of Zr or Hf, particularly between 0 and 3%, could replace part of the titanium. The formula of the alloy is then:
N.sub.aAu.sub.bM.sub.cT.sub.d
where a, b, c, d are atomic proportions such that:
a+b+c+d=1,
0.45a0.55;
0.41b0.495;
0.025c0.13;
0.001d0.025,
where N is a composition of titanium, zirconium, hafnium, the atomic percent of zirconium being comprised between 0% and 3% of the alloy, the atomic percent of hafnium being comprised between 0% and 3% of the alloy.
where M represents one or more elements taken from among a first group including Nb, V, Pd, Pt, Fe,
where the gold content is greater than or equal to 750,
and where T represents a maximum of two elements taken from among a second group including Nb, V, Pd, Pt, Fe, Mo, Ta, W, Co, Ni, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, B, Si, Ge, Sn, Sb, In, with the exception of the metals M comprised in this alloy.

(30) The invention further concerns a timepiece or components for timepieces or for jewellery made from such a light, precious gold-titanium based alloy.

(31) The invention has many advantages resulting from the aforementioned features: these alloys have moderate hardnesses less than or equal to 300 HV, and can therefore be shaped using ordinary deformation methods; they can be classified with a fineness of 18 carats; they are especially light in comparison to most alloys classified as 18 carat gold; the nickel-free variant alloys are not dangerous for the human body.

(32) The manufacture of external timepiece components from one of the aforecited alloys can advantageously optimise the alloy composition in different respects:

(33) by adding elements that lower the melting point to facilitate implementation;

(34) by changing the amount of the element that replaces the precious metal to change the mechanical properties of the alloy;

(35) by making various slight modifications to obtain alloys with structural hardening.