Method for manufacturing alloys of precious metals and alloys of precious metals thus obtained
AssigneeThe Swatch Group Research and Development Ltd
InventorsCsilla MIKO, Rémi GROSJEAN, Jean-Luc BAZIN
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Abstract
A method for manufacturing an alloy formed from a boride of a precious metal, may involve reacting a source of the precious metal with a source of boron in a salt or a mixture of salts in the molten state. An alloy formed from a boride of a precious metal may include crystalline nanoparticles of MxBy with M being a precious metal, distributed in an amorphous matrix of B or in an amorphous matrix of B and of MzBa.
Claims31
A method for manufacturing a powder of alloy of a boride of a precious metal from the precious metal and from boron, the method comprising:
- mixing a source of the boron, a source of the precious metal, and salt(s) in the solid state to obtain a mixture;
- heating the mixture to a temperature between 100 and 1000° C. to react the source of the boron and the source of the precious metal in order to obtain the metal boride of the precious metal to obtain a heated mixture;
- cooling the heated mixture;
- separating solidified salt(s) from the boride of the precious metal, the boride of the precious metal being in form of the powder including aggregates formed by crystalline nanoparticles of the boride of the precious metal, MxBy, distributed in a matrix of amorphous boron B, a y/x ratio of the crystalline nanoparticles being greater than or equal to 1,
- wherein the precious metal is selected from the group consisting of gold, silver, platinum, palladium, ruthenium, and iridium, and
- wherein the method comprises reacting the source of the precious metal with the source of the boron in the salt(s) in molten state.
The method of 13, comprising:
- mixing the powder resulting from the micronization of the ingot with the polymer binder in order to obtain a feedstock;
- subjecting the feedstock to the injection or micro-injection to create a green body, shaped corresponding to a profile of a desired part;
- eliminating the polymer binder in the green body by debinding, during which the green body is treated chemically, then thermally in a furnace to burn residual polymer binder, the debinding being carried out in gaseous phase in an atmosphere of nitric acid or of oxalic acid and at a temperature in a range of from 100 to 140° C., to obtain a brown body;
- sintering the brown body under a protected atmosphere and at a temperature in a range of from 700 to 1800° C. in order to obtain the desired part.
An alloy, comprising a boride of a precious metal comprising gold, silver, platinum, palladium, ruthenium, and iridium,
- wherein the alloy comprises crystalline nanoparticles of a formula MxBy, with M being the precious metal,
- wherein a y/x ratio of the crystalline nanoparticles is greater than or equal to 1,
- wherein the crystalline nanoparticles are distributed in an amorphous matrix of boron or in an amorphous matrix of boron boride of the precious metal of a formula MzBa with z and a being equal to or less than x and y, respectively.
Dependencies are inferred from the claim text.