CERAMIC HOROLOGY OR JEWELLERY COMPONENT

Abstract

A horology or jewellery component, characterised in that it contains phase silicon nitride in a percentage by volume comprised between 99% and 100%.

Claims

1. A horology or jewellery component, comprising phase silicon nitride in a percentage by volume comprised between 99% and 100%.

2. The horology or jewellery component according to claim 1, wherein the component has an HV hardness comprised between 3,000 and 3,500.

3. The horology or jewellery component according to claim 1, wherein the component is an external part or a movement component.

4. The horology or jewellery component according to the claim 1, wherein the component is a button, a crown or a horology stone.

5. The horology or jewellery component according to claim 3, wherein the component is a glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention relates to a horology or jewellery component made of y phase silicon nitride (Si.sub.3N.sub.4). In the field of horology, this can be an external part such as the middle, back, bezel, button, crown, valve, wristlet link, dial, hand, dial index, etc. It can also be a movement component such as a horology stone.

[0011] This -phase silicon nitride component has a hardness greater than or equal to 3,000 HV, and can reach up to 3,500 HV.

[0012] The component is made from a powder or from a powder blend. For example, this can be the commercial powder SN-E10, by Ube Industries, Ltd., Ube, Japan. The powder blend can consist of 20% -Si.sub.3N.sub.4 and 80% -Si.sub.3N.sub.4 or 100% -Si.sub.3N.sub.4. Sintering is done in MAP (MultiAnvil Press) equipment; the press can be of the KAWAI type. This press makes it possible to apply extreme pressures of up to 45 GPa using anvil assemblies that apply force to encapsulated powder. The capsule can be made of platinum. Sintering is carried out at a temperature comprised between 1,600 C. and 1,900 C., preferably between 1,650 C. and 1,850 C., at a dwell time ranging from twenty minutes to sixty minutes under a pressure greater than or equal to 10 GPa, preferably greater than or equal to 15 GPa. The achievable pressure will be greater for smaller components, making it particularly suitable for making buttons, crowns and horology stones.

[0013] Preferentially, the component obtained is composed of 100% by volume of -phase Si.sub.3N.sub.4. However, it cannot be ruled out that a fraction of less than or equal to 1% by volume of and/or phase Si.sub.3N.sub.4 may be present, the presence of the different phases being quantified by X-ray diffraction in accordance with standard NF EN 13925. This fraction of less than or equal to 1% could also comprise impurities such as Na, Ca, P, Fe, Ni, Cl.

[0014] The component has a hardness comprised between 3,000 HV and 3,500 HV measured in accordance with ISO 14705:2016. Another feature is that it is transparent.