DE102017222495A1 - Sensor with thermal shock resistant substrate - Google Patents

Abstract

Sensor, in particular high-temperature sensor, comprising at least one substrate (3) having a first side and a second side opposite the first side; and at least one first sensor structure (7) arranged at least in regions on the first side of the substrate (3), wherein the substrate (3) comprises an oxide-ceramic fiber composite material. The present invention also relates to a use of a sensor and a method (1000) for producing a sensor.

Description

The present invention relates to a sensor for determining gas parameters. The present invention also relates to a method for producing a sensor.

Various sensors for the analysis of gases are known from the prior art. Such sensors are often used in the exhaust system of internal combustion engines, for example as temperature sensors, soot sensors, flow sensors and as multi-sensors, which may comprise a combination of different sensor types. The combustion gases or exhaust gases of such internal combustion engines may, depending on the position of the sensor in the exhaust gas system relative to the engine, have a very high temperature. Therefore, when the sensor cools down, correspondingly very high temperature gradients can occur, which can adversely affect the functioning of the sensor. Also, these sensors, depending on use, to ensure the functionality, permanently or at certain intervals are actively brought to a certain temperature level for pyrolytic cleaning. Therefore, the sensors should have a high thermal shock resistance, i. a high resistance to strong temperature changes. For example, such changes in temperature can also be caused by exposure to condensate droplets.

An example of a sensor that can be used in the exhaust line of an internal combustion engine, is in the WO 2007/048573 A1 described. The sensor comprises a flow sensor element with a temperature measuring element and a heating element. These elements are arranged on a carrier element, wherein the temperature measuring element has a Platindünnfilmwiderstand on a ceramic substrate for temperature measurement and is heated with an additional platinum thin film resistor.

An example of a soot sensor with heating element is in the WO 2006/111386 A1 shown. The soot sensor described has a sensor structure on a substrate for determining a soot occupancy. To burn off carbon black, a heating conductor is arranged on the substrate as a thin-film structure made of platinum.

However, the known from the prior art sensors have the disadvantage that these sensors have only a low thermal shock resistance to rapid changes in temperature. This low thermal shock resistance often manifests itself in cracks and / or other changes in the material of the substrate.

It is therefore an object of the present invention to provide an improved sensor which overcomes the disadvantages of the prior art. In particular, to provide a high temperature resistant sensor with increased crack resistance of the substrate and which is inexpensive to manufacture.

This object is achieved by a sensor according to the subject of claim 1.

The sensor according to the invention, in particular high-temperature sensor, has for this purpose: at least one substrate with a first side and a second side opposite the first side; and
at least one first sensor structure arranged at least partially on the first side of the substrate, wherein the substrate comprises an oxide-ceramic fiber composite material.

According to the invention, the substrate comprises an oxide-ceramic fiber composite material. For this purpose, the substrate can also be formed from an oxide-ceramic fiber composite material. By "oxide-ceramic fiber composite material" can be understood a material in which ceramics such as Al 2 O 3 are mixed with glass fibers or ceramic fibers prior to a subsequent firing of the substrate. The resulting oxide ceramic fiber composite material may have a thickness of 10-20 microns.

For the purposes of the present invention, "sensor structure" can be understood to mean any structure which is adapted to detect at least one gas parameter of a gas flowing past. Furthermore, the term "sensor structure" can also be used to designate a resistance conductor track or heating conductor track, which heats up at least in regions when a current flows through it.

With the invention, for the first time it has been possible to provide a sensor for high-temperature applications, which has a high thermal shock resistance and withstands high temperature changes essentially without damage. Compared to the known from the prior art substrates show fewer and smaller cracks, which do not propagate substantially on the surface of the substrate.

In one example, the oxide-ceramic fiber composite comprises fibers of silica, alumina, titania, baria, boria, zirconia, and / or any mixtures thereof, and / or matrices comprising alumina. Silicon oxide, magnesium oxide, barium oxide and / or zirconium oxide, preferably, the oxide ceramic fiber composite material comprises a matrix of alumina and zirconia as a binder auxiliary.

Advantageously, a very high strength of the substrate can be achieved by a matrix of aluminum oxide and zirconium oxide as the binding agent.

In a further example, the sensor has at least one first covering layer, arranged at least in regions on the first side of the substrate, wherein the first covering layer is arranged at least in regions between the substrate and the first sensor structure, and / or at least one second covering layer is arranged at least in regions the second side of the substrate, wherein the second cover layer is at least partially disposed between the substrate and a second sensor structure.

In one example, the first cover layer and / or the second cover layer comprises a glass layer, a ceramic layer, and / or a layer comprising platinum and glass.

Advantageously, surface defects on the substrate can be compensated by arranging a first and / or second cover layer, the connection of the sensor structure to the substrate can be improved, and increased stability after a thermal shock can be achieved.

For example, in a simple but working example, a covering layer comprising platinum and glass, for example a mixture of SiO 2, BaO, Al 2 O 3, can be screen printed on the substrate. This covering layer has the function of a bonding agent layer and promotes a good connection of the sensor structure to the substrate. The sensor structure can then likewise be arranged on the covering layer by means of screen printing. Subsequently, the arrangement can be fired in one step. The fired arrangement may have a thickness of 15-20 μm.

In another example, instead of a cover layer comprising platinum and glass, a cover layer comprising glass may be screen printed on the substrate and baked. Advantageously, it is possible to smooth out unevennesses and microcracks in the substrate by means of this covering layer. Subsequently, the sensor structure can be arranged on the baked cover layer and also baked.

In yet another example, the sensor has at least one first insulation layer arranged at least in regions on the first cover layer and / or on the first sensor structure; and / or the sensor has at least one second insulation layer, arranged at least in regions on the second cover layer and / or on the second sensor structure, wherein the first and / or second insulation layer is a glass, a metal oxide, a ceramic and / or a mixture of a Glass, metal oxide and / or ceramic.

Advantageously, the first sensor structure and / or the second sensor structure can be protected by such an insulation layer / insulation layers.

• zumindest eine erste Mantelschicht angeordnet zumindest bereichsweise auf der ersten Isolationsschicht; und/oder
• zumindest eine zweite Mantelschicht angeordnet zumindest bereichsweise auf der zweiten Isolationsschicht.

In another example, the sensor has:

• at least a first cladding layer arranged at least partially on the first insulating layer; and or
• at least a second cladding layer arranged at least partially on the second insulating layer.

Such a cladding layer may be used as a passivation layer, which may contain, for example, quartz glass and optionally a ceramic, as it is also known, for example, in US Pat DE 10 2007 046 900 B4 is described.

In one example, the first sensor structure and / or a second sensor structure comprise / at least one resistance structure for temperature measurement, in particular a meander-shaped measurement resistance.

The measuring resistor can be formed from a conductor track with a curved course between two electrodes. For example, the conductor track can be configured meander-shaped. Such a measuring resistor may be arranged only on one side, either on the first or the second side of the substrate. In another example, a measuring resistor may also be arranged on both sides of the substrate.

Furthermore, in the above-mentioned example, the first sensor structure and / or the second sensor structure may comprise / comprises at least one comb structure, IDK structure, for measuring a concentration of a deposit of soot particles.

Typically, IDK structures can be used to determine soot particles in a soot sensor.

In yet another example, the first sensor structure and / or the second sensor structure comprises at least one electrical heating element and at least one temperature sensor for anemometric measurement.

Such sensor structures can be used in flow sensors, which can also be referred to as flow sensors, to measure a throughput in a channel, for example in an exhaust gas line.

Also, different sensor structures, for determining different sizes, can be arranged on both sides of the substrate. Such a sensor may be referred to as a multi-sensor.

In another example, the first sensor structure and / or the second sensor structure comprise / comprises at least one noble metal, preferably platinum.

Advantageously, the sensor structure (s) can have a platinum resistance as a measuring resistor.

The invention also proposes a use of a sensor according to one of the preceding claims, in particular in the exhaust system of a motor vehicle, as a temperature sensor, soot sensor, flow sensor, gas sensor, inertial sensor, impedance sensor, heat flow sensor, flow sensor and / or as a multi-sensor, which is a combination of two or more the said sensors comprises.

• Bereitstellen zumindest eines Substrat mit einer ersten Seite und einer der ersten Seite gegenüberliegenden zweiten Seite, wobei das Substrat einen oxidkeramischen Faserverbundwerkstoff umfasst; und
• Aufbringen zumindest einer ersten Sensorstruktur zumindest bereichsweise auf der ersten Seite des Substrats.

Furthermore, the invention proposes a method for producing a sensor, in particular a high-temperature sensor, comprising the steps:

• Providing at least one substrate having a first side and a second side opposite the first side, the substrate comprising an oxide-ceramic fiber composite; and
• Applying at least a first sensor structure at least partially on the first side of the substrate.

For example, the sensor structure can be applied as a platinum layer to the substrate in thin-film technology or in thick-film technology. For this purpose, platinum powder can be mixed with oxides and binders and applied to the substrate by screen printing. Subsequently, a tempering can take place.

• Anordnen zumindest einer ersten Abdeckschicht zumindest bereichsweise auf der ersten Seite des Substrats zumindest bereichsweise zwischen dem Substrat und der ersten Sensorstruktur, und/oder
• Anordnen zumindest einer zweiten Abdeckschicht zumindest bereichsweise auf der zweiten Seite des Substrats zumindest bereichsweise zwischen dem Substrat und der zweiten Sensorstruktur, wobei die erste Abdeckschicht und/oder die zweite Abdeckschicht bevorzugt eine Glasschicht, eine Keramikschicht, und/oder eine Schicht umfassend Platin und Glas umfassen/umfasst.

In one example, the method further includes:

• Arranging at least a first cover layer at least partially on the first side of the substrate at least partially between the substrate and the first sensor structure, and / or
• Arranging at least partially on the second side of the substrate at least in regions between the substrate and the second sensor structure, the first covering layer and / or the second covering layer preferably comprising a glass layer, a ceramic layer, and / or a layer comprising platinum and glass / covers.

• Anordnen zumindest einer ersten Isolationsschicht zumindest bereichsweise auf der ersten Abdeckschicht und/oder auf der ersten Sensorstruktur; und/oder
• Anordnen zumindest einer zweiten Isolationsschicht zumindest bereichsweise auf der zweiten Abdeckschicht und/oder auf der zweiten Sensorstruktur, wobei die erste und/oder zweite Isolationsschicht ein Glas, ein Metalloxid, eine Keramik und/oder eine Mischung aus einem Glas, einem Metalloxid und/oder einer Keramik umfassen/umfasst.

In yet another example, the method further includes:

• Arranging at least one first insulating layer at least in regions on the first covering layer and / or on the first sensor structure; and or
• Arranging at least a second insulating layer at least partially on the second cover layer and / or on the second sensor structure, wherein the first and / or second insulating layer, a glass, a metal oxide, a ceramic and / or a mixture of a glass, a metal oxide and / or a Ceramics include / comprises.

• Anordnen zumindest einer ersten Mantelschicht zumindest bereichsweise auf der ersten Isolationsschicht; und/oder
• Anordnen zumindest einer zweiten Mantelschicht zumindest bereichsweise auf der zweiten Isolationsschicht.

In the above example, the method may further include:

• Arranging at least a first cladding layer at least partially on the first insulating layer; and or
• Arranging at least a second cladding layer at least partially on the second insulating layer.

Further features and advantages of the invention will become apparent from the following description, are explained in the preferred embodiments of the invention with reference to schematic drawings.

• 1 eine schematische Draufsicht auf einen Sensor gemäß einer Ausführungsform der Erfindung;
• 2 eine schematische Explosionsdarstellung eines Sensors gemäß einer Ausführungsform der Erfindung; und
• 3 ein Verfahren zur Herstellung eines Sensors gemäß einer Ausführungsform der Erfindung.

Showing:

• 1 a schematic plan view of a sensor according to an embodiment of the invention;
• 2 a schematic exploded view of a sensor according to an embodiment of the invention; and
• 3 a method of manufacturing a sensor according to an embodiment of the invention.

In 1 is a schematic plan view of a sensor 1 according to an embodiment of the invention. In the embodiment shown is on the substrate 3 a first cover layer 5 on the first side of the substrate 3 between the substratum 3 and a first sensor structure 7 arranged.

In the embodiment shown, an IDK structure for determining soot particles is the first sensor structure 7 on the substrate 3 arranged. In embodiments not shown, the first sensor structure 7 Also include other / alternative structures that are adapted to detect one or more gas parameters of a passing gas. In the example shown, the first sensor structure is used to determine soot particles 7 heated. As a heater, a resistance track, located below the first sensor structure 7 is located (not shown), used. For example, a second sensor structure, not shown, may be disposed on a second side of the substrate and the region A at the first sensor structure 7 heat. In an embodiment, not shown, the first sensor structure 7 in addition to the IDK structure still have a heat conductor for heating the IDK structure.

Also, in the 1 an area B shown with a large temperature gradient from right (cold) to left (hot), which simultaneously represents an area with a high susceptibility to cracking or breakage. In this area, the substrates used in the prior art are often damaged.

In 2 is a schematic exploded view of a sensor 1 according to an embodiment of the invention. The sensor shown by way of example 1 can the in 1 shown sensor 1 his. The sensor 1 has a substrate 3 which comprises an oxide-ceramic fiber composite material.

Optionally, in the in 2 shown embodiment, a first cover layer 5 shown on the first side of the substrate 3 is arranged. For example, the first cover layer 5 be applied by screen printing and comprise a glass layer, a ceramic layer, and / or a layer comprising platinum and glass. The first covering layer 5 can fully cover a surface of the substrate 3 cover, or only on a portion of the surface of the substrate 3 be arranged.

On the substrate 3 or on the optionally applied first cover layer 5 is a first sensor structure 7 arranged, which is executed as an IDK structure. The first sensor structure 7 can, as it is in 2 is shown to have two connectors around the sensor structure 7 to connect to an evaluation (not shown in 2 ). As an alternative or in addition to the illustrated IDK structure, it is also possible, in embodiments not shown, for further sensor structures or heating elements on the first side of the substrate 3 be arranged.

Furthermore, in the 2 only optionally shown that the first sensor structure 7 and areas of the cover layer 5 not from the first sensor structure 7 are covered by a first insulating layer 9 at least partially covered. The first insulation layer 9 may in turn, only optional, of a cladding layer 11 be at least partially covered. However, the person skilled in the art knows that an insulation layer 9 and / or a cladding layer 11 are not necessary for the use of in 2 shown sensor 1 as a temperature sensor, soot sensor, flow sensor, and / or as a multi-sensor, for example in the exhaust system of a motor vehicle.

In the in 2 shown embodiment is on the second side of the substrate 3 a second cover layer 5 ' arranged, which is a same material as the first cover layer 5 may include.

In the embodiment shown, an example of a meander structure is a second sensor structure 7 ' on the substrate 3 arranged. The meander structure shown can be used, for example, to the substrate 3 to heat up and / or to measure the temperature. In alternative embodiments not shown herein, the second sensor structure 7 ' Also include other / alternative structures that are adapted to detect one or more gas parameters of a passing gas.

Also, as already stated herein with respect to the first side of the all-ceramic heater 3 described on the second sensor structure 7 ' at least partially a second insulation layer 9 ' be arranged on the turn, at least in some areas, a second cladding layer 11 ' can be arranged.

An arrangement of structures on the second side of the substrate 3 but is not essential for the invention. A sensor according to the invention 1 may just be a substrate 3 and a first sensor structure 7 include.

• Bereitstellen 1010 zumindest eines Substrat mit einer ersten Seite und einer der ersten Seite gegenüberliegenden zweiten Seite, das Substrat einen oxidkeramischen Faserverbundwerkstoff umfasst; und
• Aufbringen 1020 zumindest einer ersten Sensorstruktur zumindest bereichsweise auf der ersten Seite des Substrats.

3 shows a method 1000 for producing a sensor according to an embodiment of the invention. The procedure 1000 has the following steps:

• Provide 1010 at least one substrate having a first side and a second side opposite the first side, the substrate comprising an oxide-ceramic fiber composite material; and
• apply 1020 at least a first sensor structure at least partially on the first side of the substrate.

• Anordnen 1030 zumindest einer ersten Abdeckschicht zumindest bereichsweise auf der ersten Seite des Substrats zumindest bereichsweise zwischen dem Substrat und der ersten Sensorstruktur, und/oder
• Anordnen 1040 zumindest einer zweiten Abdeckschicht zumindest bereichsweise auf der zweiten Seite des Substrats zumindest bereichsweise zwischen dem Substrat und der zweiten Sensorstruktur, wobei die erste Abdeckschicht und/oder die zweite Abdeckschicht bevorzugt eine Glasschicht, eine Keramikschicht, und/oder eine Schicht umfassend Platin und Glas umfassen/umfasst, und/oder
• Anordnen 1050 zumindest einer ersten Isolationsschicht zumindest bereichsweise auf der ersten Abdeckschicht und/oder auf der ersten Sensorstruktur; und/oder
• Anordnen 1060 zumindest einer zweiten Isolationsschicht zumindest bereichsweise auf der zweiten Abdeckschicht und/oder auf der zweiten Sensorstruktur, wobei die erste und/oder zweite Isolationsschicht ein Glas, ein Metalloxid, eine Keramik und/oder eine Mischung aus einem Glas, einem Metalloxid und/oder einer Keramik umfassen/umfasst, und/oder
• Anordnen 1070 zumindest einer ersten Mantelschicht zumindest bereichsweise auf der ersten Isolationsschicht; und/oder
• Anordnen 1080 zumindest einer zweiten Mantelschicht zumindest bereichsweise auf der zweiten Isolationsschicht.

Furthermore, the method can also have the following steps:

• arrange 1030 at least a first cover layer at least partially on the first side of the substrate at least partially between the substrate and the first sensor structure, and / or
• arrange 1040 at least a second covering layer at least in regions on the second side of the substrate at least in regions between the substrate and the second sensor structure, wherein the first covering layer and / or the second covering layer preferably comprise a glass layer, a ceramic layer, and / or a layer comprising platinum and glass / includes, and / or
• arrange 1050 at least a first insulation layer at least partially on the first cover layer and / or on the first sensor structure; and or
• arrange 1060 at least a second insulating layer at least partially on the second covering layer and / or on the second sensor structure, wherein the first and / or second insulating layer is a glass, a metal oxide, a ceramic and / or a mixture of a glass, a metal oxide and / or a ceramic include / includes, and / or
• arrange 1070 at least a first cladding layer at least partially on the first insulating layer; and or
• arrange 1080 at least a second cladding layer at least partially on the second insulating layer.

The features set forth in the foregoing description, in the claims and in the figures may be essential to the invention in its various embodiments both individually and in any combination.

LIST OF REFERENCE NUMBERS

1

sensor

3

substratum

5, 5 '

first / second cover layer

7, 7 '

first / second sensor structure

9, 9 '

first / second insulation layer

11, 11 '

first / second cladding layer

A

Area A

B

Area B

1000

Method for producing a sensor

1010

Produce

1020

apply

1030

Arrange first cover layer

1040

Arrange second cover layer

1050

Arrange first insulation layer

1060

Arrange second insulation layer

1070

Arrange first cladding layer

1080

Arrange second cladding layer

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2007/048573 A1 [0003]
• WO 2006/111386 A1 [0004]
• DE 102007046900 B4 [0022]

Claims (15)

Sensor, in particular high-temperature sensor, comprising: at least one substrate (3) having a first side and a second side opposite the first side; and at least one first sensor structure (7) arranged at least in regions on the first side of the substrate (3), characterized in that the substrate (3) comprises an oxide-ceramic fiber composite material. Sensor after Claim 1 characterized in that the oxide-ceramic fiber composite comprises fibers of silica, alumina, titania, baria, boria, zirconia, and / or any mixtures thereof, and / or comprising matrices comprising alumina, silica, magnesia, baria, and / or zirconia the oxide ceramic fiber composite has a matrix of alumina and zirconia as a binder. Sensor after Claim 1 or 2 , characterized in that the sensor comprises: at least a first covering layer (5) arranged at least in regions on the first side of the substrate (3), wherein the first covering layer (5) at least partially between the substrate (3) and the first sensor structure (7 ), and / or at least one second covering layer (5 ') is arranged at least in regions on the second side of the substrate (3), wherein the second covering layer (5') is arranged at least in regions between the substrate (3) and a second sensor structure (7 ') is arranged. Sensor after Claim 3 , characterized in that the first covering layer (5) and / or the second covering layer (5 ') comprises / comprises a glass layer, a ceramic layer, and / or a layer comprising platinum and glass Sensor after Claim 3 or 4 , characterized in that the sensor comprises: at least one first insulating layer (9) arranged at least in regions on the first covering layer (5) and / or on the first sensor structure (7); and / or at least one second insulating layer (9 ') arranged at least in regions on the second covering layer (5') and / or on the second sensor structure (7 '), wherein the first and / or second insulating layer (9') comprises a glass, a metal oxide, a ceramic and / or a mixture of a glass, a metal oxide and / or a ceramic / includes. Sensor after Claim 5 , characterized in that the sensor comprises: at least a first cladding layer (11) disposed at least partially on the first insulating layer (9); and / or at least one second cladding layer (11 ') arranged at least partially on the second insulating layer (9'). Sensor according to one of the preceding claims, characterized in that the first sensor structure (7) and / or a second sensor structure (7 ') comprises / comprises at least one resistance structure for temperature measurement, in particular a meander-shaped measuring resistor comprises / comprises. Sensor according to one of the preceding claims, characterized in that the first sensor structure (7) and / or the second sensor structure (7 ') comprises / comprises at least one comb structure, IDK structure, for measuring a concentration of a deposit of soot particles. Sensor according to one of the preceding claims, characterized in that the first sensor structure (7) and / or the second sensor structure (7 ') comprises / comprises at least one electrical heating element and at least one temperature sensor for anemometric measurement. Sensor according to one of the preceding claims, characterized in that the first sensor structure (7) and / or the second sensor structure (7 ') comprise / comprises at least one noble metal, preferably platinum. Use of a sensor according to one of the preceding claims, in particular in the exhaust system of a motor vehicle, as a temperature sensor, soot sensor, flow sensor, gas sensor, inertial sensor, impedance sensor, heat radiation sensor, flow sensor and / or as a multi-sensor comprising a combination of two or more of said sensors. A method of manufacturing a sensor, in particular a high-temperature sensor, comprising the steps: Providing (1010) at least one substrate (3) having a first side and a second side opposite the first side, the substrate (3) comprising an oxide-ceramic fiber composite; and Applying (1020) at least one first sensor structure (7) at least in regions on the first side of the substrate (3). Method according to Claim 12 , comprising: arranging (1030) at least one first covering layer (5) at least in regions on the first side of the substrate (3) at least in regions between the substrate (3) and the first sensor structure (7), and / or arranging (1040) at least partially on the second side of the substrate (3) at least in some areas between the substrate (3) and the at least one second covering layer (5 ') second sensor structure (7 '), wherein the first covering layer (5) and / or the second covering layer (5') preferably comprises / comprises a glass layer, a ceramic layer, and / or a layer comprising platinum and glass. Method according to Claim 12 or 13 , comprising: arranging (1050) at least one first insulation layer (9) at least in regions on the first covering layer (5) and / or on the first sensor structure (7); and / or arranging (1060) at least one second insulation layer (9 ') at least in regions on the second cover layer (5') and / or on the second sensor structure (7 '), wherein the first and / or second insulation layer (9, 9' ) comprises / comprises a glass, a metal oxide, a ceramic and / or a mixture of a glass, a metal oxide and / or a ceramic. Method according to Claim 14 , comprising: arranging (1070) at least one first cladding layer (11) at least in regions on the first insulating layer (9); and / or arranging (1080) at least one second cladding layer (11 ') at least in regions on the second insulating layer (9').

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