DD270325A1 - GOLD-COLORED HARD COAT LAYER - Google Patents

Abstract

The well-known green content of TiN layers is often distracting in decorative applications. While avoiding the use of gold, it is proposed to store copper at least in the outer layer in a ratio of 0.5 to 10 atomic percent in the TiN. This produces whitish-to-reddish-golden hard coatings. {Titanium nitride layer, decorative, whitish gold to reddish gold, inclusion of copper in TiN}

Description

Field of application of the invention

The invention relates to a gold-colored hard material layer based on hard titanium nitride layers, which are deposited by means of PVD methods. The field of application is especially where the known greenish gold of titanium nitride is distracting, z. B. jewelry, costume jewelery and souvenirs, and cases and straps for watches and eyeglass frames.

Characteristic of the known state of the art

The well-known fact that TiN layers have a gold tone having a relatively high green content has resulted in numerous approaches that have enabled os to realize a variety of gold tones.

The processes that enable TiN-Au to build up a layer take up a large space. The base layer of TiN brings the required layer hardness and the relatively thin top layer of gold the desired real gold tone, which adjusts itself to the Go'dsorte used. Layer structure, methods and devices are numerous known (JP 58-217674, JP 59-205476, DE-OS 3428951). The alternating coating of TiN and Au had also found application (GB 2166162, US-PS 91418, DE-OS 3606623). By mixing of liquid gold compounds to the reaction gas nitrogen different gold tones could also be realized (DE-OS 34 25468). Furthermore, it was possible by additions of carbon to the reactive oxygen gas to realize a reddish-golden hue without green content (JP 59-35676, DE-OS 3425467).

By ion implantation of gold in the TiN layer, it was also possible to realize different gold tones (JP 59-35673). In most solutions it is disadvantageous that gold and gold compounds are used at least in the cover layer, whereby the material used for the layer is very expensive. The preparation of TiCN layers allows a reddish gold tone, but not the production of the whitish gold tone.

Object of the invention

The invention aims to produce gold-colored hard coatings for decorative applications in the hue range from whitish to reddish gold without the use of gold or gold compounds.

Explanation of the essence of the invention The invention is based on the object, known per se, produced by PVD method, TiN layer by means of To modify additives such that in a present at least in the top layer homogeneous layer structure of the

bekarr.ie green share is suppressed.

According to the invention the object is achieved in that the decorative gold-colored hard material layer at least in the Cover layer of a homogeneous mixture of plasma-assisted reactive deposited titanium nitride and copper, wherein

the Cu content is 0.5 to 10 at%.

The preparation of such layers can be carried out by means of known parallel evaporation of titanium and copper. While that Titanium under the reactive conditions is deposited to a large extent as titanium nitride, the copper only roasts

insignificant and is incorporated in its metallic form in the titanium nitride layer (TiN _x ). This leaves the optical

Effect of copper received. In low copper conditions, the color is whitish-gold, at higher proportions reddish-gold. With an increase of the copper content beyond the specified range of the invention, the character of the Hard material layer based on the titanium nitride lost. The layer structure can be designed homogeneously throughout. But there are also different gradients possible. The Transition to the substrate can also be designed in many ways. For example, a first adhesion-promoting

metallic layer can be arranged on the basis of titanium or copper.

With the layer according to the invention is a very good gold-colored TiN layer without Grünanteii and without Einsau of gold

possible. The layers can be produced economically and represent qualitatively new titanium nitride hard coatings.

AutfQhrungsbeisplel The invention will be explained in more detail below with reference to an exemplary embodiment. Watch cases and associated watch straps should be coated with the layer of the invention

whitish-golden Is and has no disturbing Qrünanteil.

For the preparation of a reactive plasma process with hollow cathode arc evaporator and additional probe evaporator

used.

After known pre-cleaning of the substrates, the following layer combination is built up. Substrate-80 nm Ti - nm TiN _x - 1000 nm TiN _x -Cu _y .

The Ti layer is deposited under a non-reactive atmosphere, whereby the titanium is evaporated from the hollow cathode arc evaporator. Without interruption process the reactive gas is mixed with nitrogen, and it is the TiN _x layer is deposited. Finally, the probe evaporator, in which the copper is stored, is placed on the positive potential opposite the cathode, whereby electrons are extracted from the plasma to the copper while maintaining the remaining process parameters. This leads to a co-evaporation. The rate ratios Ti: Cu are regulated via the corresponding potentials.

In the example, the parameters are chosen such that the Cu content of the TiN _x -Cu _y -Schi <: ht is 2 atomic%. The hardness of the layer is HV _o , o2 = 2 500 kpnm " ^2. This layer is adherent, hard, whitish-golden and resistant to synthetic perspiration.

Claims (2)

1. Gold-colored hard material layer for decorative applications in the color range whitish to reddish gold, characterized in that at least ·: the top layer of a homogeneous mixture of plasma-assisted reactive deposited titanium nitride and copper, wherein the copper content is 0.5 to 10 atomic%. 2. Gold-colored hard material layer according to claim 1, characterized in that one of the two metallic components between the hard material layer and the substrate is arranged as an adhesion-promoting layer.