Process of depositing a hard coating of a gold compound on a substrate for coating jewelry and the like
AssigneeASU Composants S.A.
InventorErich Bergmann
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Abstract
The invention relates to a process of deposition of a coating of a gold compound on a solid substrate. In a vacuum chamber (1), the substrate is fixed on a first substrate electrode (2). A composite target (5) essentially consists of gold and at least one of the metal compounds, such as nitride, carbide and boride of the metals of group IV b of the periodic classification of elements and tantalum. A high-purity argon atmosphere at pressure ranging between 4.times.10.sup.-4 and 3.times.10.sup.-2 Torr is then established in the chamber. The deposition of the coating is then carried out by ionic deposition or evaporation in vapor phase at a given rate. The invention may find application to coat articles of jewelry or of watch cases.
Claims10
An article of jewelry comprising a solid substrate, and a coating on said substrate, said coating comprising a gold composite consisting essentially of at least one member of the group consisting of gold, silver, rhodium, palladium, platinum, iridium and osmium and at least one nitride, carbide or boride of a metal selected from the group consisting of the Group IV b elements and tantalum, said coating containing, depending upon its thickness, an opposite gradient of concentration by volume of said at least one member and said at least one nitride, carbide or boride.
A piece of jewelry comprising a solid substrate and a metal coating on said substrate, said coating consisting essentially of at least one member of the group consisting of gold, silver, rhodium, palladium, platinum, iridium and osmium and at least one nitride, carbide or boride, of a metal selected from the group consisting of the Group IV b elements and tantalum, wherein the metal coating contains, depending on its thickness, an opposite gradient of concentration by volume of said at least one member and said at least one nitride, carbide and boride.
Dependencies are inferred from the claim text.