Component with a Layer into which CNT (Carbon Nanotubes) are Incorporated and a Method for the Manufacture of Said Component

Abstract

A component with a layer with CNT incorporated into thereof is disclosed. Particles of a dry lubricant are also embedded into the layer. The layer is particularly suited for electrical contact surfaces due to the embedded CNT. Further provided is a method for electrochemically producing the layer in which preferably ionic fluids are used as an electrolyte.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2009 / 057788, filed Jun. 23, 2009 and claims the benefit thereof. The International Application claims the benefits of German application No. 10 2008 030 988.5 DE filed Jun. 27, 2008. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The invention relates to a component with a layer with CNT incorporated into the grains thereof.BACKGROUND OF INVENTION[0003]A layer with CNT, as mentioned above, can typically be produced on a contact element as described in WO 2007 / 118337 A1. This electrical contact element is used for closing and opening an electrical contact and is subject to great stress during this process. This stressing is attributable to the transmission of the electrical switching current, wherein, in accordance with WO 2007 / 118337 A1, an increase in the service life of the contact is to be achieved by...

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Benefits of technology

[0005]This object is inventively achieved with the component mentioned at the start by a dry lubricant being incorporated into the grains in addition to the CNT particles. The background of the inventive measure is that the incorporation of CNT, contrary to the widely-held belief among those skilled in the art, only inadequately improves the wear behavior of a coating. CNT does actually improve the hardness of the coating, but the tribological behavior of surfaces is not solely influenced by their hardness. Instead the lubricating properties of the coating during frictional stress are also of primary importance. This is the starting point of the invention, in that the particles of a dry lubricant are also incorporated in addition to the CNT. Dry lubricants belong to a material group characterized by its ability to improve the lubricating properties of the surfaces involved. This advantageously reduces wear, which enables the component into the grains of which CNT and particles of a dry lubricant are incorporated to achieve a better service life. In this case the grains of the layer form a matrix in which the particles of the dry lubricant and the CNT, which can also be regarded as particles, are distributed dispersed. Because of their dimensions, the CNT represent nanoparticles. The particles of the dry lubricant can be embodied as nanoparticles but can also have dimensions in the micrometer range.

[0007]A further embodiment of the invention is obtained if the layer has metallic grains, especially made of a nickel-cobalt alloy. The metallic grains of the layer make it possible to conduct the electrical current with advantageously low electrical resistance. Nickel-cobalt alloys in particular are suitable for electrical switching elements since they combine comparatively good electrical and thermal conductivity with a satisfactory wear behavior. Thus the optimization potential through the incorporation of CNT and dry lubricant particles can advantageously be used especially well.

[0008]In accordance with another embodiment of the invention there is provision for the layer to have a ceramic grain or at least ceramic grain proportions, especially made of oxidic or nitridic ceramics such as titanium nitride. This advantageously enables very hard layers, for coating a tool for example, to be produced, with their tribological behavior able to be optimized by embedding of the dry lubricant particles. This enables the service life to be advantageously improved. At the same time the thermal conductivity of the CNT can be used in order for example to effectively dissipate the heat from cutting tools. The reduction in thermal stress advantageously simultaneously leads, at high cutting speeds of the tool, to an improved service life, or makes it possible to cut at higher speeds with the same service life.

[0015]Another especially advantageous form of embodiment of the inventive method is obtained if an ionic fluid is used as an electrolyte for the coating. Fluid salts in which the salt is not dissolved in a solvent (preferably water) are referred to as ionic liquids. This involves organic liquids which are composed of cations and anions. In the present case alkalized imidazolium, pyridinium, ammonium or phosphonium ions are used as cations. Simple halogenides, tetrafluorborate, hexafluorphosphate, Bi(trifluoromethylsulfonyl)imide or Tri(pentafluoroethyl)trifluorphosphate can typically be used as anions. The effect of choosing these cations and anions is that the ionic fluids are available in the fluid state at temperatures of below 100° C., preferably even at room temperature. Because of their chemical structure, ionic fluids possess surfactant-type properties, which is why these fluids are excellently well suited to the production of dispersions. The ionic fluid acts in such cases as a means of dispersion, with the dispersants to be dispersed able to be microparticles or nanoparticles and being formed in the invention by the CNT and the particles of the dry lubricant. Advantageously this enables wetting agents for dispersal to be dispensed with, which avoids the properties of the particles incorporated into the electrochemically-fabricated layer being adversely affected by built-in wetting agents. In addition comparatively high concentrations of dispersed particles can be achieved in ionic fluids, whereby higher incorporation rates into the layer to be created are also advantageously achieved.

[0016]In addition the metals can also be deposited from the ionic fluid as nano crystalline metal layers. In this regard the parameters in accordance with WO 2006 / 061081 A2 or information provided by F. Endres, “Ionische Flüssigkeiten zur Metallabscheidung (Ionic fluids for metal deposition)”, Nachrichten aus der Chemie, 55, May 2007, Pages 507 to 511, should be taken into account. The structure of nano crystalline metal layers is advantageously especially well suited to the incorporation of CNT as well as the particles of the dry lubricant, so that advantageously especially high incorporation rates can be achieved.

Problems solved by technology

The background of the inventive measure is that the incorporation of CNT, contrary to the widely-held belief among those skilled in the art, only inadequately improves the wear behavior of a coating.

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