Sensory layer system and uses thereof

Abstract

Sensory layer system containing or consisting of: a) a base layer, wherein the base layer has at least one property selected from the group consisting of electrically insulating, piezoresistive and thermoresistive, wherein the base layer is arranged on a component; b) a sensor structure arranged on the base layer and adapted to detect a parameter selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas, and combinations thereof, wherein the sensor structure contains or consists of a metal; and c) at least one electrical conductor track structure arranged on the base layer and electrically connected to the sensor structure; d) a cover layer arranged on the base layer and in which the sensor structure and the at least one electrical conductor structure are embedded at least in part, wherein the cover layer is a multilayer layer containing or consisting of at least a first layer and at least a second layer, wherein the at least one first layer and the at least one second layer are arranged one above the other, wherein the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semi-metal and / or gas, and combinations thereof, wherein the second layer contains or consists of a material different from the first layer, and wherein the first layer and second layer each have a layer thickness in the range of 1 nm to 1000 nm, characterized in that the multilayer layer contains or consists of n first layers and n second layers which are arranged alternately in the multilayer layer, where n is an integer in the range from 2 to 100, and the second layer is a layer of the cover layer and forms a final layer of the layer system.

Description

[0001] A sensory layer system is provided which has a base layer and a cover layer and is characterized in that the cover layer is a multilayer coating which contains or consists of at least a first layer and at least one second layer, wherein the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semimetal and / or gas, and combinations thereof, and the second layer contains or consists of a material different from the first layer. The first layer and the second layer each have a layer thickness in the range of 1 nm to 1000 nm.The multilayer coating can provide improved electrical insulation and greater long-term stability against wear compared to established single insulation layers with a relatively flat and compact design, thereby expanding its application limits.

[0002] Sensor layer systems with an insulating layer but without a wear-resistant layer are known in the state of the art. The insulating layers used to achieve electrical insulation include, for example, layers of Al2O3, SiO xor aC:H:Si:O (Biehl, S. et al., Microsyst. Technol., 22:1757-1765 and Schmaljohann, F., Meas. Sci. Technol., 23:074019). Due to the lack of a wear-resistant layer, the service life of these known sensory coating systems is not very long. Especially in highly stressed applications, there is a need to ensure greater wear protection for these coating systems. At the same time, the coating systems must be electrically insulated from possible counter-bodies (tool parts, molded parts, workpiece / material, etc.) to which the coating systems are applied.

[0003] The sensory layer system known from DE 10 2018 218 300 A1 does indeed ensure a certain degree of mechanical stability through the presence of a relatively strong intermediate layer and a certain degree of wear protection through the presence of a wear protection layer, but for highly stressed applications such as drive components, tools, components, the durability of this layer system is in need of improvement.

[0004] It is known in the art to use electrically insulating layers with alternating materials as wear protection layers (Frach, P. et al., Surface & Coatings Technology, 202:5680-5683 and Bakeev, IY, et al., 14th International Conference "Gas Discharge Plasmas and Their Application", Journal of Physics: Conference Series, 1393:012074). Specifically, Al2O3 and SiO2 layers are deposited using various vacuum coating processes or electron beam evaporation, with the layer thicknesses of the individual layers ranging from 1 µm to 8 µm per layer. However, this approach is not particularly advantageous for use in thin-film sensor systems, as the individual layer thicknesses are relatively high at 1 µm to 8 µm and can therefore negatively impact the sensitivity and durability of the sensor technology. Furthermore, the materials Al2O3 and SiO2 have disadvantages with regard to their tribological properties (e.g.high specific friction coefficients) and bonding properties (e.g. weak adhesion to layers of the sensory layer system and / or to components).

[0005] DE 10 2012 022 113 A1 discloses a force measuring device comprising a crystalline layer having piezoelectric properties arranged on at least part of a surface of a solid-state actuator (or carrier), and at least one wear protection layer having anti-friction properties, wherein the piezoelectric layer consists of crystalline aluminum nitride having a hexagonal crystal structure with a pronounced crystal orientation (002), wherein at least one electrically conductive layer is applied between the surface of the solid-state actuator and the crystalline aluminum nitride layer.

[0006] DE 10 2010 054 970 A1 discloses a device comprising a strain gauge structure mounted on a carrier made of a plastic material selected from polyimide, wherein an electrically insulated layer is arranged between the strain gauge structure and the carrier, and an upper surface of the carrier is planarized and / or passivated by the electrically insulated layer.

[0007] DE 10 2018 125 631 A1 discloses a layer system comprising a friction and wear-reducing protective layer, wherein the protective layer comprises doped tetrahedral amorphous carbon.

[0008] DE 10 2020 120 113 A1 discloses a precision component of a rolling or plain bearing, comprising a sensor element for pressure and temperature measurement with the following layer structure on a metallic base material: an insulating layer located on the base material, a pressure-sensitive sensor layer, an insulating layer covering the pressure-sensitive layer, a temperature sensor layer located on this insulating layer, an insulating layer covering the temperature sensor layer, and a wear protection layer which is flush with a rolling contact surface formed by the base material.

[0009] Based on this, the object of the present invention was to provide a sensory layer system that is electrically insulated, has the flattest possible design, and enables high long-term stability against wear (e.g., due to the high mechanical stability of individual layers of the layer system and strong adhesion between the individual layers). Preferably, the sensory layer system should also exhibit maximum sensitivity and durability of the sensor technology. In particular, the layer system should also enable a strong connection to a component (e.g., via a base layer of the layer system) and have the smallest possible coefficient of friction (e.g., on a cover layer or final layer of the layer system). Furthermore, uses of the sensory layer system should be proposed.

[0010] The object is achieved by the sensory layer system having the features of claim 1 and the use having the features of claim 11. The dependent claims show advantageous developments.

[0011] According to the invention, a sensory layer system is provided containing or consisting of: a) a base layer, wherein the base layer has at least one property selected from the group consisting of electrically insulating, piezoresistive and thermoresistive (preferably: electrically insulating), wherein the base layer is arranged on a component; b) a sensor structure arranged on the base layer and adapted to detect a parameter selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas, and combinations thereof, wherein the sensor structure contains or consists of a metal; c) at least one electrical conductor track structure arranged on the base layer and electrically connected to the sensor structure; d) a cover layer arranged on the base layer and in which the sensor structure and the at least one electrical conductor structure are embedded at least in part, wherein the cover layer is a multilayer layer containing or consisting of at least one first layer and at least one second layer, wherein the at least one first layer and the at least one second layer are arranged one above the other, wherein the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semi-metal and / or gas, and combinations thereof, wherein the second layer contains or consists of a material different from the first layer, and wherein the first layer and second layer each have a layer thickness in the range of 1 nm to 1000 nm, characterized in that the multilayer contains or consists of n first layers and n second layers arranged alternately in the multilayer, where n is an integer in the range from 2 to 100, and the second layer is a layer of the cover layer and forms a final layer of the layer system.

[0012] A first layer (e.g., the cover layer) that is "arranged" on a second layer (e.g., the base layer) is understood, in particular, to mean that at least one further layer (e.g., an intermediate layer) can be arranged between the first layer (e.g., the cover layer) and the second layer (e.g., the base layer), i.e., that the first layer does not necessarily contact the second layer. If no further layer is arranged between the first and second layers, the first layer may contact the second layer.

[0013] The sensory coating system according to the invention has the advantage that the multilayer coating provides improved electrical insulation and greater long-term wear resistance compared to established single insulation layers (such as single layers of aC:H:Si:O), even with a relatively flat (i.e., compact) design. This expands the application limits of the coating system, especially for tribologically demanding applications (e.g., on tools, components, and / or drive elements) and for areas with high loads or difficult accessibility (e.g., on test benches, production machines, wind turbines, bridges, and cranes).

[0014] According to the invention, the multilayer of the layer system contains or consists of n first layers and n second layers, which are arranged alternately in the multilayer, where n is an integer in the range from 2 to 100, particularly preferably in the range from 3 to 60, in particular in the range from 4 to 40, optionally in the range from 5 to 30.

[0015] Furthermore, the multilayer of the layer system can have a layer thickness in the range of 0.5 µm to 6 µm, preferably in the range of 1 µm to 4 µm. The total layer thickness of the layer system is thus relatively low, which enables a compact design. Since this thickness is achieved over at least two layers, i.e., each individual layer of the multilayer has a relatively low thickness, the sensitivity and durability of the sensor technology of the layer system are not negatively affected to the same extent as with a single layer with a thickness in this range.

[0016] In addition, the multilayer coating of the coating system can have a universal hardness HU, determined according to the standard ISO 14577-1:2015-07, in the range of 9 to 34 GPa.

[0017] In addition, the multilayer coating of the coating system can achieve an abrasive wear rate, determined according to DIN EN 1071, in the range of ≤ 6·10 -15m 3 / (N·m).

[0018] In addition, the multilayer coating of the coating system can have a specific electrical resistance in the range of at least 1.5·10 12 Ω mm 2 / m. In this case, the multilayer coating has electrically insulating properties.

[0019] Furthermore, the multilayer coating of the coating system (preferably the top layer) can have a friction coefficient, determined according to DIN 50324-07, in the range of ≤ 0.3. This improves the long-term stability of the coating system.

[0020] The first layer and / or second layer of the multilayer layer, preferably all layers of the multilayer layer, can each have a layer thickness in the range from 2 nm to 1000 nm, preferably 10 nm to 500 nm, particularly preferably 50 nm to 200 nm.

[0021] Furthermore, the first layer and / or second layer of the multilayer layer, preferably all layers of the multilayer layer, can be produced by a process selected from the group consisting of PACVD, PVD and combinations thereof, wherein a material selected from the group consisting of methane, tetramethylsilane, hexamethylsiloxane and combinations thereof was optionally used in the process.

[0022] The first layer of the multilayer coating may contain or consist of a diamond-like carbon modified with at least hydrogen, preferably a material selected from the group consisting of aC:H, aC:H:Si, aC:H:Si:O and combinations thereof.

[0023] Furthermore, the first layer of the multilayer coating may contain or consist of aC:H:Si:O and / or aC:H:Si and the second layer may optionally contain or consist of aC:H.

[0024] According to the invention, the first layer of the multilayer coating is a layer of the cover layer and preferably contacts the base layer or an intermediate layer of the layer system.

[0025] The second layer of the multilayer coating can contain or consist of a material selected from the group consisting of diamond-like carbon, diamond-like carbon modified with a metal, semimetal and / or gas, ceramic and combinations thereof, wherein the material is preferably selected from the group consisting of diamond-like carbon modified with at least hydrogen, nitride ceramic, oxide ceramic and combinations thereof, wherein the material is particularly preferably selected from the group consisting of aC:H, aC:H:Si, aC:H:Si:O, CrAlN, CrN, chromium oxide, silicon oxide, aluminum oxide, zirconium oxide and combinations thereof.

[0026] Furthermore, the second layer of the multilayer coating may contain or consist of aC:H:Si:O and / or aC:H:Si and the first layer may optionally contain or consist of aC:H.

[0027] The sensor structure and / or electrical conductor structure may contain or consist of a metal selected from the group consisting of titanium, gold, silver, chromium, NiCr, nickel, platinum and combinations thereof.

[0028] The layer system can have an electronic evaluation unit which is electrically conductively connected to the at least one electrical conductor track structure, wherein the electronic evaluation unit is preferably configured to evaluate measured values ​​of the sensor structure (optionally also of a further sensor structure of the layer system) and to use the evaluated measured values ​​to control a component to which the layer system is applied.

[0029] The sensor structure can be arranged in areas on the intermediate layer where forces greater than bending moments act.

[0030] Furthermore, the sensor structure can be designed as a strain gauge structure and / or temperature sensor structure.

[0031] The base layer may have piezoresistive and thermoresistive properties and the layer system may further contain: i) a further sensor structure which is electrically connected to the at least one electrical conductor structure and is suitable for detecting a parameter selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas and combinations thereof, wherein the sensor structure contains or consists of a metal; and ii) an intermediate layer which is arranged between the base layer and the cover layer and in which the further sensor structure and the at least one electrical conductor structure are embedded at least in some areas.

[0032] Preferably, the intermediate layer is a multilayer layer as described above, ie a multilayer layer which contains or consists of at least one first layer and at least one second layer, wherein the at least one first layer and the at least one second layer are arranged one above the other and the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semimetal and / or gas, and combinations thereof, and the second layer contains or consists of a material different from the first layer.

[0033] The at least one electrical conductor track structure of the layer system is electrically conductively connected to the further sensor structure and the cover layer of the layer system is arranged on the intermediate layer.

[0034] The first layer of the multilayer intermediate layer can contact the base layer and / or the top layer.

[0035] Furthermore, the second layer of the multilayer layer of the intermediate layer can contact the base layer and / or the cover layer.

[0036] The additional sensor structure can have at least one feature that the sensor structure of the layer system also has. For example, the additional sensor structure can contain or consist of a metal selected from the group consisting of titanium, gold, silver, chromium, NiCr, nickel, platinum, and combinations thereof.

[0037] The additional sensor structure can be arranged in areas on the base layer where larger bending moments than forces act.

[0038] The base layer can be characterized by the fact that no sensor system is embedded in the base layer.

[0039] According to the invention, the base layer is arranged on a component, wherein the component is preferably selected from the group consisting of tool, drive element, bearing, gear, module, washer and combinations thereof, wherein the component is particularly preferably selected from the group consisting of kingpin, trailer coupling of a towing vehicle, washer for a screw fastening, forming tool, machine element, insert, production machine, wind turbine, bridge, crane and combinations thereof.

[0040] According to the invention, the use of the layer system according to the invention for detecting at least one parameter on the component is further proposed, wherein the at least one parameter is selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas and combinations thereof.

[0041] The use can be characterized in that the component is selected from the group consisting of tool, drive element, bearing, gear, module, washer and combinations thereof, wherein the component is preferably selected from the group consisting of kingpin, trailer coupling of a towing vehicle, washer for a screw fastening, forming tool, machine element, insert, production machine, wind turbine, bridge, crane and combinations thereof.

Claims

[1] Sensory layer system containing or consisting of: a) a base layer, wherein the base layer has at least one property selected from the group consisting of electrically insulating, piezoresistive and thermoresistive, wherein the base layer is arranged on a component; b) a sensor structure arranged on the base layer and adapted to detect a parameter selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas, and combinations thereof, wherein the sensor structure contains or consists of a metal; and c) at least one electrical conductor track structure arranged on the base layer and electrically connected to the sensor structure; d) a cover layer arranged on the base layer and in which the sensor structure and the at least one electrical conductor structure are embedded at least in part, wherein the cover layer is a multilayer layer containing or consisting of at least a first layer and at least a second layer, wherein the at least one first layer and the at least one second layer are arranged one above the other, wherein the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semi-metal and / or gas, and combinations thereof, wherein the second layer contains or consists of a material different from the first layer, and wherein the first layer and second layer each have a layer thickness in the range of 1 nm to 1000 nm, characterized by, that the multilayer layer contains or consists of n first layers and n second layers which are arranged alternately in the multilayer layer, where n is an integer in the range from 2 to 100, and the second layer is a layer of the cover layer and forms a final layer of the layer system. [2] Layer system according to the preceding claim, characterized by that the multilayer coating i) contains or consists of n first layers and n second layers arranged alternately in the multilayer, where n is an integer in the range from 3 to 60, in particular in the range from 4 to 40, optionally in the range from 5 to 30; and / or ii) has a layer thickness in the range of 0.5 µm to 6 µm, preferably 1 µm to 4 µm. [3] Layer system according to one of the preceding claims, characterized bythat the first layer and / or second layer, preferably all layers of the multilayer layer, each i) has a layer thickness in the range from 2 nm to 1000 nm, preferably 10 nm to 500 nm, particularly preferably 50 nm to 200 nm; and / or ii) is produced by a process selected from the group consisting of PACVD, PVD and combinations thereof, wherein the process optionally uses a material selected from the group consisting of methane, tetramethylsilane, hexamethylsiloxane and combinations thereof. [4] Layer system according to one of the preceding claims, characterized by that the first layer i) contains or consists of a diamond-like carbon modified with at least hydrogen, preferably a material selected from the group consisting of aC:H, aC:H:Si, aC:H:Si:O and combinations thereof; and / or ii) contains or consists of aC:H:Si:O and / or aC:H:Si and the second layer optionally contains or consists of aC:H; and / or iii) the base layer or an intermediate layer of the layer system is contacted. [5] Layer system according to one of the preceding claims, characterized by that the second layer i) contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semi-metal and / or gas, ceramic and combinations thereof, wherein the material is preferably selected from the group consisting of a diamond-like carbon modified with at least hydrogen, nitride ceramic, oxide ceramic and combinations thereof, wherein the material is particularly preferably selected from the group consisting of aC:H, aC:H:Si, aC:H:Si:O, CrAlN, CrN, chromium oxide, silicon oxide, aluminum oxide, zirconium oxide and combinations thereof; and / or ii) contains or consists of aC:H:Si:O and / or aC:H:Si and the first layer optionally contains or consists of aC:H. [6] Layer system according to one of the preceding claims, characterized bythat the sensor structure and / or electrical conductor structure contains or consists of a metal selected from the group consisting of titanium, gold, silver, chromium, NiCr, nickel, platinum and combinations thereof. [7] Layer system according to one of the preceding claims, characterized by that the layer system has an electronic evaluation unit which is electrically conductively connected to the at least one electrical conductor track structure, wherein the electronic evaluation unit is preferably configured to evaluate measured values ​​of the sensor structure and to control a component to which the layer system is applied using the evaluated measured values. [8] Layer system according to one of the preceding claims, characterized by that the base layer has piezoresistive and thermoresistive properties and the layer system also contains: i) a further sensor structure which is electrically connected to the at least one electrical conductor structure and is suitable for detecting a parameter selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas and combinations thereof, wherein the sensor structure contains or consists of a metal; and ii) an intermediate layer arranged between the base layer and the cover layer and in which the further sensor structure and the at least one electrical conductor structure are embedded at least in part; wherein the intermediate layer is preferably a multilayer layer which contains or consists of at least one first layer and at least one second layer, wherein the at least one first layer and the at least one second layer are arranged one above the other and the first layer contains or consists of a material selected from the group consisting of diamond-like carbon, a diamond-like carbon modified with a metal, semi-metal and / or gas, and combinations thereof and the second layer contains or consists of a material different from the first layer, wherein the at least one electrical conductor track structure is electrically conductively connected to the further sensor structure, and wherein the cover layer is arranged on the intermediate layer. [9] Layer system according to claim 8, characterized by that the further sensor structure i) contains or consists of a metal selected from the group consisting of titanium, gold, silver, chromium, NiCr, nickel, platinum and combinations thereof; and / or ii) is arranged in areas on the base layer where forces greater than bending moments act. [10] Layer system according to one of the preceding claims, characterized by that the component is selected from the group consisting of tool, drive element, bearing, gear, module, washer and combinations thereof, wherein the component is particularly preferably selected from the group consisting of kingpin, trailer coupling of a towing vehicle, washer for a screw fastening, forming tool, machine element, insert, production machine, wind turbine, bridge, crane and combinations thereof. [11] Use of the layer system according to one of the preceding claims for detecting at least one parameter on the component, wherein the at least one parameter is selected from the group consisting of force, temperature, strain, deformation, distance, movement, speed, flow, vibration, structure-borne sound, pressure, gas and combinations thereof. [12] Use according to claim 11, characterized by that the component is selected from the group consisting of tool, drive element, bearing, gear, module, washer and combinations thereof, wherein the component is preferably selected from the group consisting of kingpin, trailer coupling of a towing vehicle, washer for a screw fastening, forming tool, machine element, insert, production machine, wind turbine, bridge, crane and combinations thereof.