Ceramic element and method for manufacturing the same

Abstract

The present invention relates to a ceramic substrate (10) having at least one metallization layer (20) on at least one surface (11) and at least one feedline (30) in electrical contact with said metallization layer (20), and an encapsulation structure (40) surrounding said ceramic substrate (10), said at least one metallization layer (20), and a first segment (31) of said at least one feedline (30), said first segment (31) being directly adjacent to said metallization layer (20). a protective layer (50) surrounding the encapsulation structure (40) and a second segment (32) of the at least one supply line (30), the second segment (32) being directly adjacent to the first segment (31); and an insulating layer (60) surrounding the protective layer (50) and a third segment (33) of the supply line (30), the third segment (33) being directly adjacent to the second segment (32). The present invention further provides a method for manufacturing a ceramic element.

Description

[Technical Field]

[0001] TECHNICAL FIELD This application relates to ceramic elements and methods for making ceramic elements. [Background technology]

[0002] Electroceramic elements used as resistive elements in electronic devices are known. In particular, electroceramic elements with variable resistance characteristics, such as temperature-sensitive resistors, are known. Temperature-sensitive resistors include cold conductors or PTC resistors (PTC = Positive Temperature Coefficient), whose ceramics have better electrical conductivity at low temperatures than at high temperatures, and hot conductors or NTC resistors (NTC = Negative Temperature Coefficient), whose ceramics are characterized by increasing conductivity or decreasing resistance with increasing temperature. NTC resistors or NTC thermistors are used in various fields, such as automobiles, home appliances, or industrial applications, for example, as sensor elements for temperature measurement. This measurement can be used to set, regulate, and control temperature.

[0003] Conventional ceramic elements usually have an insulating layer to protect them from external environmental influences, such as water vapor, humidity, or other media, but under operating conditions with increasing operating time and / or operating temperature, they often exhibit unacceptable changes in the resistance-temperature characteristic curve and thus loss of functionality, such as when NTC resistors are used as temperature sensors in automotive applications. In view of the above, at least one embodiment of the present invention aims to provide a ceramic element with improved properties. Summary of the Invention

[0004] The present invention provides a solution to achieve the above object in the form of a ceramic element and a method for manufacturing a ceramic element according to the independent claims. Advantageous technical solutions of said element and said method are the subject of the further claims.

[0005] The present invention provides a ceramic element, according to at least one embodiment, comprising a ceramic substrate having at least one metallized layer on at least one surface and at least one feedline in electrical contact with the metallized layer.

[0006] The ceramic substrate may include or consist of a ceramic. The ceramic substrate may have a variety of geometric shapes. For example, the ceramic substrate may be cubic.

[0007] "At least one surface" here and hereinafter refers to a portion of the entire surface of the ceramic substrate. If the ceramic substrate is, for example, cubic in shape, the at least one surface may include one of the sides of the cube. If the metallization layer is present on multiple surfaces of the substrate, for example, on two surfaces of the substrate, these surfaces are spatially separated portions of the entire surface. If the substrate is, for example, a cube, the metallization layer may be present on two opposing sides of the substrate, for example.

[0008] The at least one metallization layer is applied to the substrate in this way so that the substrate can be electrically contacted by the metallization layer, and in particular, the at least one metallization layer is in direct mechanical contact with the ceramic substrate.

[0009] The supply lines may in particular be metal lines. "Electrical contact" is understood in particular as a direct mechanical connection between at least one supply line and a metallization layer.

[0010] According to at least one embodiment, the ceramic device further comprises an encapsulation structure surrounding the ceramic substrate, the at least one metallization layer, and the first segment of the at least one feedline, the first segment being directly adjacent to the metallization layer, where "surrounding" refers to the encapsulation structure completely covering all exposed surfaces of the ceramic substrate, the at least one metallization layer, and the first segment of the feedline, and where the encapsulation structure may have a common interface with and / or surround the ceramic substrate, the at least one metallization layer, and / or the first segment of the at least one feedline to form a cavity.

[0011] According to at least one embodiment, the ceramic element further comprises a protective layer surrounding the encapsulation structure and the second segment of the at least one feed line, the second segment being directly adjacent to the first segment. "Surrounding" here refers to the protective layer completely covering the entire exposed surface of the encapsulation structure and the second segment of the at least one feed line. In particular, no cavities, such as air bubbles, exist between the encapsulation structure and the protective layer, and between the second segment of the feed line and the protective layer. Therefore, the encapsulation structure and the protective layer, and the second segment of the feed line and the protective layer, respectively, have a common interface, particularly over the entire surface.

[0012] The second segment of the at least one supply line is disposed adjacent to the first segment, i.e., on the opposite side of the first segment from the metallization layer, so that the protective layer is disposed indirectly on the first segment of the at least one supply line and directly on the second segment of the at least one supply line.

[0013] According to at least one other embodiment, the ceramic element further comprises an insulating layer surrounding the protective layer and the third segment of the supply line, the third segment being directly adjacent to the second segment. "Surrounding" here means that the insulating layer completely covers the entire exposed surface of the protective layer and the third segment of the at least one supply line. In particular, no cavities, such as air bubbles, exist between the insulating layer and the protective layer, and between the insulating layer and the third segment of the at least one supply line. Therefore, the insulating layer and the protective layer, and the third segment of the supply line and the insulating layer, respectively, have a common interface, particularly over the entire surface.

[0014] The third segment of the at least one supply line is adjacent to the second segment, i.e., located on the opposite side of the second segment from the metallization layer, such that an insulating layer is indirectly disposed on the first and second segments of the at least one supply line and directly disposed on the third segment of the at least one supply line.

[0015] Thus, the first, second, and third segments of the at least one supply line refer to consecutive segments of the at least one supply line. According to at least one embodiment, the first, second, and third segments of the at least one supply line do not represent the entire supply line. In other words, the supply line has a fourth segment that is directly adjacent to the opposite side of the third segment from the second segment and is not surrounded by an encapsulation structure, protective layer, or insulating layer.

[0016] According to at least one embodiment, a ceramic substrate having at least one metallized layer on at least one surface and at least one feedline in electrical contact with said metallized layer; an encapsulation structure surrounding the ceramic substrate, the at least one metallization layer, and a first segment of the at least one feedline, the first segment being directly adjacent to the metallization layer; a protective layer surrounding the encapsulation structure and a second segment of the at least one supply line, the second segment being directly adjacent to the first segment; an insulating layer surrounding the protective layer and a third segment of the supply line, the third segment being directly adjacent to the second segment; The present invention provides a ceramic element having

[0017] The stability of the ceramic element can be improved due to the presence of an additional protective layer between the encapsulation structure and the insulating layer.

[0018] In principle, the encapsulated device is protected from the external environment by an insulating layer. However, even with the insulating layer, unacceptable changes in the resistance-temperature characteristic curve can occur when the device is in prolonged contact with water, water vapor, or large amounts of humidity, or when the device is used in a vehicle and the device is in contact with media such as exhaust gas condensate or engine oil. Here, water, water vapor, and / or media can penetrate directly through the insulating layer or along the interface between the insulating layer and the at least one supply line.

[0019] If the insulating layer is easily peeled off due to the influence of the external environment, moisture or other media can penetrate into the thin gap formed between the encapsulation structure and the insulating layer. This penetration also causes a high ion concentration dissolution effect in the material of the device. In this case, when a voltage is applied, ion migration occurs in the electric field, resulting in so-called migration defects. This can, for example, cause the at least one supply line to disintegrate. This results in an undesirable decrease in resistance, a short circuit, and even loss of functionality.

[0020] A protective layer between the encapsulation structure and the insulating layer can significantly reduce or prevent the insulating layer from peeling off. The protective layer is used as an adhesion promoter between the encapsulation structure and the insulating layer and between the supply line and the insulating layer, ensuring better or stronger connections between the insulating layer and the encapsulation structure and between the insulating layer and the supply line. In this way, the use of a protective layer can prevent the formation of the above-mentioned gaps. This makes it more difficult or prevents any penetration of moisture and / or other media, effectively suppressing electromigration.

[0021] Compared to conventional components that do not include such a protective layer, the element's moisture barrier properties and resistance to other media improve its long-term stability, even when used at high temperatures, for example up to 260°C.

[0022] According to at least one embodiment, the device has two metallization layers on two surfaces of the substrate, each with a feed line in electrical contact with the metallization layer. All implementations relating to at least one metallization layer on at least one surface and at least one feed line are equally applicable to any other metallization layer, surface, and feed line. In this case, an encapsulation structure surrounds, for example, the ceramic substrate, the two metallization layers, and a first segment of the two feed lines, a protective layer surrounds the encapsulation structure and a second segment of the two feed lines, and an insulating layer surrounds the protective layer and a third segment of the two feed lines.

[0023] According to at least one embodiment, the protective layer comprises a material that includes an organic component and an inorganic component. Specifically, the protective layer comprises about 50 wt% of the organic component and about 50 wt% of the inorganic component. The inorganic component may include, for example, inorganic particles embedded in an organic component that forms a matrix.

[0024] According to at least one embodiment, the organic component comprises a fluorine-containing polymer and the inorganic component comprises a metal oxide. The fluorine-containing polymer may be, for example, a perfluoroalkoxy polymer. The metal oxide may be selected from FeO, SiO2, SnO, Al2O3, and combinations thereof. The metal oxide particles may be embedded in the fluorine-containing polymer.

[0025] According to at least one embodiment, the protective layer has a thickness selected from the range of 1 μm to 250 μm. The material of the protective layer may have low or high viscosity when applied, depending on its specific components. When a low-viscosity material is used, the protective layer may have a thickness in the range of 1 μm to 25 μm. When a high-viscosity material is used, the protective layer may have a thickness in the range of 20 μm to 250 μm.

[0026] According to at least one embodiment, a chemical bond and / or chemical interaction exists between the protective layer and the encapsulating structure and / or between the protective layer and the insulating layer. Such a bond and / or interaction can enhance the adhesive effect of the protective layer between the insulating layer and the encapsulating structure. For example, if the encapsulating structure includes a glass, i.e., oxide network, a metal oxide contained in the protective layer can, for example, react with the oxide network to ensure better connection between the encapsulating structure and the protective layer. For example, if the insulating layer includes a fluorine-containing polymer, the polymer can, for example, form a uniform organic network with the fluorine-containing polymer in the protective layer, thereby providing a good connection between the insulating layer and the protective layer.

[0027] According to at least one embodiment, the ceramic substrate comprises a ceramic material having a negative temperature coefficient of resistance. Thus, the ceramic substrate is an NTC element or NTC chip. The ceramic material having a negative temperature coefficient of resistance can be selected from spinels, which have the general composition AB2O4 and contain divalent metal ions B 2+ are located at tetrahedral sites in the crystal lattice, and trivalent metal ions B3+ is located in the octahedral sites of the crystal lattice. Spinel may be, for example, an oxide composition of the elements Mn, Co, and Ni. Spinel ceramics can achieve different resistance values ​​and slopes of the characteristic curve (so-called B-values) depending on the specific application.

[0028] According to at least one embodiment, the encapsulation structure comprises glass, so that the ceramic element is a wired element encapsulated in glass, i.e. a so-called glass sensor.

[0029] According to at least one embodiment, the insulating layer is made of a material selected from fluorine-containing organic polymers. Specifically, perfluoroalkoxy polymer (PFA) can be selected as the material for the insulating layer. When a DC voltage of 100 V is applied, the insulation resistance of such a PFA insulating layer exceeds 100 MΩ.

[0030] According to at least one embodiment, the at least one metallization layer comprises Au.

[0031] According to at least one embodiment, the at least one feedline comprises a metal selected from Fe, Ni, Cu, and combinations thereof. The feedline may, for example, comprise a Cu-coated FeNi alloy.

[0032] According to at least one embodiment, the ceramic element further comprises a contact metal surrounding the at least one supply line and the at least one metallization layer in the region where the supply line and the metallization layer have a common interface. The contact metal is, in particular, Au. The contact metal ensures, in particular, a good and stable fixation of the supply line to the metallization layer.

[0033] According to at least one embodiment, the ceramic element is configured as an NTC sensor, which can be used in particular for temperature measurement, for example in the automotive sector.

[0034] The present invention further provides a method for manufacturing a ceramic element, said method being suitable for manufacturing the ceramic element described herein, and therefore all features and embodiments relating to the ceramic element apply to said method and vice versa.

[0035] According to at least one embodiment, the method for manufacturing the ceramic element comprises: providing a ceramic substrate; disposing at least one metallized layer on at least one surface of the ceramic substrate; placing the at least one metallization layer in electrical contact with a supply line; forming an encapsulation structure surrounding the ceramic substrate, the at least one metallization layer, and a first segment of the at least one feedline, the first segment being directly adjacent the metallization layer; forming a protective layer surrounding the encapsulation structure and a second segment of the at least one supply line, the second segment being directly adjacent to the first segment; applying an insulating layer surrounding a protective layer and a third segment of the at least one supply line, the third segment being directly adjacent to the second segment; Includes:

[0036] According to at least one embodiment, the step of disposing at least one metallization layer on at least one surface of the ceramic substrate comprises applying and fixing a material for forming the metallization layer. According to at least one embodiment, the application is performed by printing, particularly screen printing. According to at least one embodiment, the fixing is performed by heating, particularly firing. The heating is performed at a temperature in the range of 800°C to 890°C, particularly 850°C.

[0037] According to one embodiment, gold paste is selected as the material for forming the metallization layer, which, upon heating, is fired onto at least one surface of the ceramic substrate to form the metallization layer.

[0038] According to at least one embodiment, the step of electrically contacting the at least one metallization layer with the supply line includes the steps of placing the supply line on the metallization layer and securing the supply line to the metallization layer. During placement, a portion of one segment, particularly a first segment of the supply line, is brought into mechanical contact with the metallization layer so that the metallization layer and the supply line have a common interface. According to one embodiment, the step of securing the supply line to the metallization layer includes placing a contact metal in the area where the metallization layer and the supply line have a common interface and drying the contact metal. For example, a separate gold paste may be used as the contact metal.

[0039] According to at least one embodiment, the step of forming an encapsulation structure surrounding the ceramic substrate, the at least one metallization layer, and the first segment of the at least one feed line includes placing a material for producing the encapsulation structure on the ceramic substrate, the metallization layer, and the first segment of the feed line and melting the material. The melting is particularly performed at a temperature in the range of 600°C to 800°C. The material of the encapsulation structure can be, in particular, glass. For example, a small glass tube is pressed onto the ceramic substrate having the metallization layer and the first segment of the feed line and melted. The melting forms a sealed, closed encapsulation structure with only the at least one feed line protruding. The previously applied contact metal can also be melted during the melting of the encapsulation structure material. This sinters the contact metal, permanently and stably fixing the feed line to the metallization layer.

[0040] According to at least one embodiment, the step of forming the protective layer includes applying a liquid material for forming the protective layer. According to one embodiment, the application of the liquid material is performed by a method selected from dip coating, spray coating, and roll coating. For example, in the case of dip coating, the encapsulated device may be immersed in the liquid material, where the second segment of the supply line is also immersed so as to be covered with the liquid material. For example, if the encapsulated device has a length of about 1 mm, the device may be immersed in the liquid material by up to 10 mm to apply the liquid material for the protective layer.

[0041] The liquid material for forming the protective layer may have different viscosities depending on the specific components, for example, low viscosity or high viscosity, which parameter may affect the thickness of the protective layer formed.

[0042] According to at least one embodiment, the step of forming the protective layer further includes an intermediate drying step after the step of applying the liquid material. The intermediate drying may be performed, for example, at room temperature or at an elevated temperature in the range of 90°C to 130°C. Here, the liquid material is at least partially solidified before applying the insulating layer. Alternatively, the intermediate drying step may be omitted and the insulating layer may be applied to the liquid material. This is a so-called wet process. According to one embodiment, the protective layer is completely dried after applying the insulating layer. During drying, the protective layer may function as an adhesion promoter by forming chemical bonds and / or interactions between the encapsulating structure and the protective layer and / or between the protective layer and the insulating layer.

[0043] According to at least one embodiment, the step of applying the insulating layer is performed by electrostatic powder coating. [Brief explanation of the drawings]

[0044] For further advantageous embodiments and refinements of the device and the method, please refer to the examples described below in conjunction with the drawings.

[0045] [Figure 1a] FIG. 1 is a schematic cross-sectional view illustrating a ceramic element including an encapsulation structure. [Figure 1b] FIG. 1 is a schematic cross-sectional view illustrating a ceramic element including an encapsulation structure and a protective layer. [Figure 1c] 1 is a schematic cross-sectional view illustrating a ceramic element including an encapsulation structure, a protective layer, and an insulating layer. [Figure 2] 1 is an image showing a conventional ceramic element with a Cu migration defect pattern. [Figure 3a] FIG. 10 is a diagram showing the resistance drift of elements according to an example and a comparative example. [Figure 3b] FIG. 10 is a diagram showing the resistance drift of the element according to the example. DETAILED DESCRIPTION OF THE INVENTION

[0046] The dimensional ratios of elements shown in the drawings and graphs are not to scale, and identical or similar elements are designated by the same reference numerals.

[0047] 1a is a schematic cross-sectional view of an encapsulated device. This embodiment shows the ceramic device before its fabrication is completed. The encapsulated device includes a ceramic substrate 10. The ceramic substrate 10 comprises an NTC ceramic, such as spinel. Two spatially separated surfaces 11 (which may also be called sub-surfaces) of the ceramic substrate 10 are coated with metallization layers 20, which in this embodiment include or consist of an Au material.

[0048] Disposed on the metallization layer 20 are feed lines 30, each having a common interface 23 with the metallization layer 20. In this example, the feed lines are Cu-coated FeNi alloy metal wires.

[0049] Also present at the common interface 23 of the metallization layer 20 and the supply line 30 is a contact metal 21, such as Au, which secures the supply line 30 to the metallization layer. A voltage can be applied to the ceramic substrate through the metallization layer 20, the supply line 30, and the contact metal 21.

[0050] Each of the feed lines 30 includes a first segment 31, indicated by two dashed lines in FIG. 1 a. The first segment 31, metallization layer 20, contact metal 21, and ceramic substrate 10 of the two feed lines 30 are surrounded by an encapsulation structure 40. The encapsulation structure 40 may include or be made of glass. The areas of the two feed lines 30 other than the first segment 31 protrude from the encapsulation structure 40.

[0051] The element shown in FIG. 1a is in particular a glass-encapsulated NTC resistor or NTC thermistor.

[0052] FIG. 1b is a schematic cross-sectional view of the ceramic element described with reference to FIG. 1a, further including a protective layer 50. Thus, FIG. 1b also illustrates an unfinished element according to one embodiment. The protective layer 50 surrounds the encapsulation structure 40 and the second segment 32 of the feed line 30, which is also indicated by a dashed line. This allows the protective layer 50 to surround a larger area than the underlying encapsulation structure 40.

[0053] The protective layer 50 is composed of a material containing organic and inorganic components. Among the ceramic element examples described below, Example B1 has a protective layer 50 composed of a fluorine-containing polymer, in this example, a perfluoroalkoxy polymer, and metal oxides SiO and AlO (e.g., Chemours' "Primer Clear" material). Example B2 has a protective layer 50 composed of a fluorine-containing polymer, in this example, a perfluoroalkoxy polymer, and metal oxides FeO, SnO, SiO, and AlO (e.g., Chemours' "Ruby Red" material). The material used to manufacture the protective layer 50 in Example B1 has a lower viscosity than the material in Example B2. For example, the protective layer 50 manufactured by a dip coating method has a thickness ranging from 1 mm to 25 μm in Example B1 and a thickness ranging from 20 μm to 250 μm in Example B2.

[0054] 1a and 1b, further comprising an insulating layer 60. The ceramic element shown here is a fabricated element according to one embodiment. The insulating layer 60 surrounds the protective layer 50 and the third segment 33 of the supply line 30. This allows the insulating layer 60 to surround a larger area than the underlying encapsulation structure 40. The insulating layer 60 may be a PFA layer applied, for example, by electrostatic powder coating.

[0055] The device in FIG. 1c is an NTC thermistor that is much more resistant to environmental influences than conventional devices that do not include a protective layer. The protective layer 50, which acts as an adhesion promoter between the encapsulation structure 40 and the insulating layer 60, prevents or significantly slows the penetration of media into the device. This prevents the solution effect and prevents the migration of ions, especially Cu ions, from the supply line 30 when a voltage is applied. This means that the device is free of migration defects and therefore does not experience undesirable changes in resistance.

[0056] 2 is an image showing a conventional device without the protective layer 50 and with a Cu migration defect pattern. The arrows indicate defects, particularly those caused by electromigration, which resulted in an undesirable change in resistance and ultimately a short circuit.

[0057] 3a and 3b show the measurement results of the resistance drift dR25 (expressed as %) of the elements according to the example and comparative example measured at 25° C. The resistance drift refers to the deviation of the nominal resistance R25 from the target value.

[0058] 3a shows the measured resistance drift dR25 of the devices according to Examples B1 and B2 and Comparative Example V. Comparative Example V does not have a protective layer 50 but has an insulating layer 60 made of PFA.

[0059] After 500 hours of storage in water at 80°C and an applied voltage of 1.2V, the resistance drift (dR25) was measured. Thirty measurements were performed for each device, and the distribution of the measurement results is plotted in Figure 3a. The nominal resistance of 1000 Ω (dR25 = 0) and the allowable resistance deviation of ±3% (dR25 = 3 or dR25 = -3) are indicated by dashed lines. As shown in Figure 3a, the two devices B1 and B2 exhibited small resistance drift, with the resistance drift approaching zero in these two examples, as indicated by the solid line at the zero line. On the other hand, Comparative Example V exhibited significant resistance drift, with values ​​mostly outside the ±3% tolerance range (gray frame). This indicates that Comparative Example V completely failed after 500 hours of storage in water. Electromigration caused a decrease in resistance, resulting in short circuits and ultimately complete failure.

[0060] Figure 3b shows a continuation of the series of experiments described in Figure 3a using devices B1 and B2. Here, the same experimental conditions as those described in Figure 3a were used, except that the storage time was varied between 500 h and 5000 h. For clarity, the y-axis only shows the resistance drift dR25, which is within the ±3% tolerance range. For these two examples, a resistance drift of less than 1% was observed even after 5000 h of storage.

[0061] In other words, as shown in the figure, by using the protective layer 50 between the encapsulation structure 40 and the insulating layer 60, the stability and service life of the ceramic element are significantly improved even when used under the influence of an external environment, such as water or water vapor. The occurrence of electromigration and migration defects can be effectively suppressed. Therefore, the ceramic element described herein far exceeds the conventional specification of about 2000 hours, for example, in the automotive industry, even when used in the presence of water, water vapor, or large amounts of moisture. [Explanation of symbols]

[0062] 10 Ceramic substrate 11 Surface 20 metallization layer 21 Contact metals 23 Common interface 30 Supply Line 31 First Segment 32 Second Segment 33 Third Segment 40 Encapsulation Structure 50 protective layer 60 insulating layer dR25 Resistance drift measured at 25°C B1 Example B2 Example V Comparative example

Claims

1. a ceramic substrate (10) having at least one metallized layer (20) on at least one surface (11) and at least one feedline (30) in electrical contact with said metallized layer (20); an encapsulation structure (40) surrounding the ceramic substrate (10), the at least one metallization layer (20), and a first segment (31) of the at least one feedline (30), the first segment (31) being directly adjacent to the metallization layer (20); a protective layer (50) surrounding the encapsulation structure (40) and a second segment (32) of the at least one supply line (30), the second segment (32) being directly adjacent to the first segment (31); an insulating layer (60) surrounding the protective layer (50) and a third segment (33) of the supply line (30), the third segment (33) being directly adjacent to the second segment (32); A ceramic element having

2. The ceramic element of the preceding claim, wherein the protective layer (150) comprises a material that includes an organic component and an inorganic component.

3. 10. The ceramic element of claim 9, wherein the organic component comprises a fluorine-containing polymer and the inorganic component comprises a metal oxide.

4. 10. The ceramic element according to any one of the preceding claims, wherein the protective layer (150) has a thickness selected from the range of 1 μm to 250 μm.

5. 10. The ceramic element according to any one of the preceding claims, wherein a chemical bond and / or a chemical interaction exists between the protective layer (50) and the encapsulation structure (40) and / or between the protective layer (50) and the insulating layer (60).

6. 10. The ceramic element of any one of the preceding claims, wherein the ceramic substrate (10) comprises a ceramic material having a negative temperature coefficient of resistance.

7. 10. The ceramic element of any one of the preceding claims, wherein the encapsulation structure (40) comprises glass.

8. 10. A ceramic element according to any one of the preceding claims, wherein the insulating layer (60) comprises a material selected from fluorine-containing organic polymers.

9. 10. The ceramic component of any one of the preceding claims, wherein the at least one metallization layer (20) comprises Au.

10. 10. The ceramic element of any one of the preceding claims, wherein the at least one feedline (30) comprises a metal selected from Fe, Ni, Cu and combinations thereof.

11. 10. The ceramic element according to claim 1, wherein the ceramic element is configured as an NTC sensor.

12. Providing a ceramic substrate (10); disposing at least one metallized layer (20) on at least one surface (11) of said ceramic substrate (10); placing said at least one metallization layer (20) in electrical contact with a supply line (30); forming an encapsulation structure (40) surrounding the ceramic substrate (10), the at least one metallization layer (20), and a first segment (31) of the at least one feedline (30), the first segment (31) being directly adjacent to the metallization layer (20); forming a protective layer (50) surrounding the encapsulation structure (40) and a second segment (32) of the at least one supply line (30), the second segment (32) being directly adjacent to the first segment (31); applying an insulating layer (60) surrounding said protective layer (50) and a third segment (33) of said at least one supply line (30), said third segment (33) being directly adjacent to said second segment (32); A method for manufacturing a ceramic element comprising:

13. 10. The method of the previous claim, wherein the step of forming the protective layer (50) comprises applying a liquid material for forming the protective layer (50).

14. 10. The method according to the preceding claim, wherein the liquid material is applied by a method selected from dip coating, spray coating and roll coating.

15. 15. The method of any one of claims 13 or 14, wherein the step of forming the protective layer (50) further comprises an intermediate drying step after the step of applying the liquid material.

Images