JOINT COMPLIMENT COMPLIMENT ENTIRELY WITH AT LEAST PARTIALLY CRYSTALLIZED GLASS, ITS USE AS WELL AS A CRYSTALLIZED AND AT LEAST PARTIALLY CRYSTALLIZED GLASS AND ITS USE

Description

[0001] The invention relates to a crystallizable or at least partially crystallized glass and its use, a product and a joining connection comprising an insulating component with at least partially crystallized glass, and its use.

[0002] There are many areas of application for joining connections, where temperature resistance, mechanical stability and resistance can be important.

[0003] If such joints, for example those used to carry electrical or electronic signals, are located in sections of exhaust systems of internal combustion engines, such as in vehicles with controlled exhaust gas purification, they are frequently subject to rapidly changing environmental conditions. For example, during cold starts, especially in colder regions or at high humidity, these joints can become coated with films of moisture from condensed atmospheric constituents. This condensation can manifest as droplet formation or even complete coverage of the joint. This can undesirably alter the electrical resistance between the components and impair the control behavior of the exhaust gas purification system.

[0004] Although extremely high-resistance insulating materials, as will be explained in more detail below using crystallizable or at least partially crystallized glasses as examples, can be used, these are often not sufficiently safe in such an environment to ensure unimpaired control behavior against the impairments described above.

[0005] Document DE 10 2008 045 816 A1 proposes an elastomeric material surrounding a conductor to extend a creepage distance, which, within the scope of this disclosure, is the distance along which creepage currents can develop between the joining partners. A disadvantage of this solution is that elastomeric materials often lack the thermal stability and fatigue strength required for the hot zone of exhaust systems.

[0006] One aspect of the present invention relates to better protecting the electrical or electronic, in particular high-resistance, properties of the insulating materials disclosed herein, especially the crystallizable or partially crystallized glasses disclosed herein, against environmental influences.

[0007] This aspect of the problem of the invention is solved by a joining connection comprising an electrically insulating component and at least two joining partners, wherein at least one of the joining partners 51, 52 is held electrically insulated from at least one other of the joining partners 51, 52 by the electrically insulating component 53, and the surface of the electrically insulating component 53, which extends between the joining partners, forms a structure S, in particular a protrusion or depression, by which in particular the direct path from the at least one joining partner to the at least one other joining partner along the surface is extended compared to a surface without this structure S, and wherein the structure preferably completely surrounds at least one joining partner, wherein the insulating component or the structure comprises or consists of crystallizable or at least partially crystallized glass and its use.

[0008] Electrically insulated holding, as defined in the present disclosure, refers to a holding method in which the DC resistance between the joining partners of the described joining connection, which are located in a dry atmosphere and on which there are no deposits that could impair this resistance, is greater than 100 MΩ, wherein this electrical resistance value is measured at voltages of less than 100 V.

[0009] The aforementioned structure S can be formed in one piece and material identical to the section of the insulating component, which extends between the joining partners, is connected to it in each case, and is preferably glazed onto them in each case, wherein the material of the insulating component preferably comprises an at least partially crystallized glass and its use.

[0010] In the transition area between the surface of the joining partner and the surface of the at least partially crystallized glass, an at least predominantly amorphous glass layer can be arranged in the joining connections disclosed herein, which preferably comprises less than 10 pores per cm³ and / or preferably has a thickness of 5 µm or less, particularly preferably 2 µm or less and most preferably 1 µm or less.

[0011] In the joining connections described here, the structure S can comprise crystallizable or at least partially crystallized glass and have at least a predominantly amorphous glass layer on the surface of the structure S, in particular a glass layer which has essentially no open pores and in particular comprises less than 10 pores / cm 3<, which has a thickness of 5 µm or less, preferably 2 µm or less and most preferably 1 µm or less.

[0012] The following also discloses embodiments of joining connections in which the structure S is not materially identical to the section of the insulating component which extends between the joining partners, is connected to it in each case and preferably glazed onto it in each case.

[0013] In such a joining connection, in which the structure S is not materially identical to the section of the insulating component, which extends between the joining partners, is connected to it and preferably glazed onto it, and comprises a high-temperature-stable ceramic material, for example Forsterite, an aluminum oxide-based ceramic or a zirconium oxide-based ceramic, for example a ceramic comprising Y-stabilized zirconium oxide.

[0014] In the joining connection, in which the structure S is not materially identical to the section of the insulating component which extends between the joining partners, is connected to it and preferably attached to it, the structure S can be arranged approximately centrally in a radial direction on this section of the insulating component and preferably projecting at least partially into it.

[0015] In an advantageous joining connection in which the structure S contains a reinforcement, the reinforcement can comprise a metal sheet, a metal foil or a metal-comprising fabric, braid or knitted fabric, wherein preferably the metal comprises or consists of steel.

[0016] In the embodiments disclosed herein, the structure S can have edges which have a radius of curvature Rv of less than one tenth of a millimeter, preferably of less than one twentieth of a millimeter and more than 10 µm.

[0017] With the crystallizable or at least partially crystallized glass according to the embodiments described here, it is possible, by means of the structure S described here, to increase the surface area of ​​the insulating material which is arranged between joining partners to be insulated from each other and thus to lengthen the creepage distance running on the surface of the insulating component.

[0018] The crystallizable or at least partially crystallized glass according to the embodiments described here allows the formation of high-temperature-stable and / or mechanically high-strength joints. As explained above, it is possible to form a particularly stable microstructure in the at least partially crystallized glass using a crystallizable or at least partially crystallized glass according to the described embodiments, in particular a microstructure that remains mechanically stable even at high temperatures up to 1000°C or even above.

[0019] Another aspect therefore concerns crystallizable glasses as well as glasses that are at least partially crystallized and are used, among other things, in the field of solder glasses.

[0020] Sealing glasses (also known as glass solders or, in English, "sealing glasses") are used to create tight joints between components to be joined. These joints are also referred to as bonded joints or welded connections.

[0021] To produce stable joints that are exposed to very high temperatures during operation, for example, temperatures of 900°C or more, and even temperatures around 1000°C, solder glasses are regularly required that can withstand these high temperatures and whose expansion behavior is adapted to the materials being joined. These materials include, for example, high-temperature-resistant metals and / or metal alloys, or high-temperature-resistant non-metallic materials such as yttrium-stabilized ZrO₂.

[0022] Furthermore, the joining connections must be hermetically sealed and, when used especially in electrical components such as in sensor technology and / or in fuel cells, must be electrically insulating, i.e., have very low electrical conductivity.

[0023] Commercially available glass solders with high thermal expansion generally have low melting temperatures, which limits their thermal stability and makes them unsuitable for high-temperature applications. Conversely, glass solders for high-temperature applications have thermal expansion coefficients that are significantly lower than those of the high-temperature-resistant joining partners.

[0024] The prior art proposes various glass solders for producing joining connections.

[0025] German patent application DE 100 16 416 A1 describes glass-ceramic melts, wherein the starting glass used consists of 38 wt.% to 48 wt.% SiO₂, 15 wt.% to 19 wt.% Al₂IO₃, 4.5 wt.% to 11 wt.% TiO₂, 0 wt.% to 1.5 wt.% Na₂O, 0 wt.% to 1.5 wt.% K₂O, and 23 wt.% to 30 wt.% CaO, with up to 1.5 wt.% Li₂O also being permissible. With these compositions, coefficients of thermal expansion of up to 8.8 × 10⁻⁶ K / K can be achieved in the temperature range of 100°C to 500°C.

[0026] German patent DE 10 2012 206 266 B3 describes a barium- and strontium-free glassy or glass-ceramic joining material and its use. To ensure sufficient wetting of the components to be joined, the joining material comprises B₂O₃.

[0027] German patent application DE 10 2014 218 983 A1 describes a feedthrough element for harsh operating conditions. Here too, the joining material comprises B₂O₃.

[0028] German patent application DE 10 2010 035 251 A9 describes a high-temperature glass solder and its use. The glass solder contains at least 10 wt% BaO. However, BaO is disadvantageous because barium reacts with the chromium contained in high-temperature steels.

[0029] The German patent application DE 10 2015 207 285 A1 describes a glassy or at least partially crystallized melting material. This contains at least 5 mol% B₂O₃.

[0030] DE 10 2011 080 352 A1 describes a high-temperature glass solder and its use. The described high-temperature glass solder comprises between 13 wt.% and 50 wt.% Al₂O₃, with SiO₂ being included only optionally in the glass solder.

[0031] US patent application US 2007 / 0238599 A1 describes highly crystalline sintered glass ceramics comprising cyclosilicates. According to one embodiment, the glass ceramics of US 2007 / 0238599 A1 comprise, as necessary components, between 30 wt.% and 55 wt.% SiO₂, between 5 wt.% and 40 wt.% CaO, and between 0.1 wt.% and 10 wt.% Al₂O₃, wherein the sum of the oxides BaO, CaO, and SrO comprised by the glass ceramic is between 40 wt.% and 65 wt.%. In other words, the glass ceramics of US 2007 / 0238599 A1 always comprise, in addition to CaO, BaO and / or SrO.

[0032] US patent application US 2010 / 0129726 A1 describes a lead-free glass with a low B 2 O 3 content, wherein the content of the glass in the oxides of SiO 2 , MgO, CaO, SrO, BaO, ZnO and Al 2 O 3 is at least 97 mol%.

[0033] Glass-ceramic compositions for seals are further described in US 2013 / 0108946 A1. These compositions consist of either SiO₂, Al₂O₃, and CaO; or of SiO₂, Al₂O₃, CaO, and SrO; or of SiO₂, Al₂O₃, and La₂O₃, as well as other selected components.

[0034] Reddy et al. describe melilith-based glasses and glass-ceramics for functional applications, such as seals, in RSC Advances, 2012, 2, 10955-10967. Bi₂O₃ acts as a crystallization agent in particular.

[0035] International patent application WO 2017 / 220700 A1 describes a compound produced with at least partially crystallized glass and a method for producing such a compound, wherein the at least partially crystallized glass has at least one crystal phase and pores that are arranged in a structured distribution within the at least partially crystallized glass.

[0036] US patent application US 2016 / 236967 A1 describes a glass composition for a crystallizable glass comprising substantially no boron oxide, alkali metal oxides, or aluminum oxide, but comprising, in mol% SiO₂: 40-55, BaO: 18-35, TiO₂ + ZrO₂: 0.1-10, ZnO: 0-15, CaO: 0-20, MgO: 0-9, SrO: 0-5, and La₂O₃: 0-2, wherein the total content of RO (with R: Mg, Ca, Sr, Ba, and Zn) is at least 44 mol%, and wherein the glass composition, when fired as a glass powder at a temperature between 850-1050°C, is transformed into a crystallized glass exhibiting a coefficient of thermal expansion of 90-150 × 10⁻⁷ K in the range of exhibits temperatures of 50-850°C.

[0037] Finally, international patent application WO 2018 / 066635 A1 describes a glass composition for joining or bonding. The composition contains 43 mol% to 53 mol% SiO₂, 12 mol% to 33 mol% CaO, 12 mol% to 33 mol% MgO, 1 mol% to 7 mol% La₂O₃, and 0 mol% to 4.5 mol% ZnO.

[0038] All of the aforementioned state-of-the-art materials have disadvantages.

[0039] Thus, the compositions according to DE 10 2012 206 266 B3, DE 10 2014 218 983 A1, and DE 10 2015 207 285 A1 necessarily include B₂O₃. The glasses described in international patent application WO 2017 / 220700 A1 also preferably comprise B₂O₃. However, B₂O₃ is a material that melts at relatively low temperatures and is therefore, as already described above, frequently used to ensure sufficient wetting of the components to be joined during melting. However, high thermal resistance of the joint cannot be achieved in this way.

[0040] If joining materials contain BaO and / or SrO, disruptive contact reactions occur with high-temperature resistant steels, which usually contain Cr.

[0041] If cyclosilicates form as crystalline phases, they exhibit thermal expansion coefficients that are too low, approximately 8 * 10 -6< / K.

[0042] High concentrations of nucleating materials, such as TiO₂, are also detrimental, as they can lead to uncontrolled crystallization of the crystallizable glass. Furthermore, in the worst-case scenario for the applications considered here, TiO₂ can even cause the formation of low-extensibility crystal phases.

[0043] At very high concentrations of components incorporated into crystal phases, as described for example in US 2010 / 0129726 A1, the wetting of the material to be joined, and thus its suitability as a joining material, is questionable.

[0044] There is therefore a need for crystallizable glasses, preferably with high thermal resistance, such as a temperature resistance of 900°C or even more, which wet the materials and / or components to be joined during melting and preferably have a high coefficient of thermal expansion.

[0045] Another aspect of the object of the present invention is therefore also to provide crystallizable glasses which overcome or at least mitigate the aforementioned weaknesses of the prior art.

[0046] This further aspect of the problem solved by the independent claims is addressed. Further developments and specific embodiments are described in the dependent claims, figures, and description.

[0047] The disclosure relating to this further aspect of the invention relates to a joining connection, in particular a high-temperature-stable and / or mechanically robust joining connection, comprising at least partially crystallized glass and a joining partner, wherein the at least partially crystallized glass comprises a residual glass content of less than 10%, preferably less than 5%, by volume. The at least partially crystallized glass comprises crystal aggregates. The crystal aggregates are formed from a plurality of crystallites. Preferably, the crystallites are needle-shaped and / or plate-shaped. Preferably, the crystallites can be arranged radially, such as spherulitic and / or fan-shaped, and / or rod-shaped and / or plate-shaped, penetrating the at least partially crystallized glass.

[0048] Such a design of a joining connection offers a number of advantages.

[0049] In particular, the low residual glass content of less than 10 vol.%, preferably even less than 5 vol.%, results in high dimensional stability of the joint.

[0050] The high dimensional stability of the joint is further advantageously ensured by the fact that the crystallites encompassed by the crystallized glass are aggregated. An acicular and / or plate-shaped structure of the crystallites is particularly advantageous. The inventors have discovered that the acicular and / or plate-shaped structure of the crystallites in the crystal aggregates leads to a mechanically stable structure of the at least partially crystallized glass. This is especially true when the preferably acicular and / or plate-shaped crystallites are arranged, for example, in a spherulitic and / or fan-shaped and / or rod-shaped or plate-like configuration, penetrating the at least partially crystallized glass.The inventors hypothesize that the preferably needle-like and / or plate-shaped structure of the crystallites, and their arrangement in, for example, spherulites, radially radiating patterns, or even rod-like and irregular patterns penetrating the at least partially crystallized glass, leads to an interlocking of the crystallites. This advantageously increases the mechanical stability of the at least partially crystallized glass, for example, against shear, compressive, or tensile forces. This interlocking can also occur in such a way that a kind of "house of cards" structure is formed.

[0051] The crystallites can also be plate-shaped, meaning they permeate the crystallized glass as small plates. In cross-sectional views, such a structure also appears as a rod, making differentiation difficult in individual cases. Within the context of this disclosure, a plate is understood to be a geometric shape in which the lateral dimension in one spatial direction of a Cartesian coordinate system (the thickness) is an order of magnitude smaller than the lateral dimensions (length, width) in the other two directions perpendicular to the first.

[0052] The disclosure further relates to a joining connection, in particular a high-temperature-stable and / or a mechanically highly resilient joining connection, comprising an at least partially crystallized glass and a joining partner, wherein the glass comprises La 2 O 3 greater than 0.3 mol% to less than 5 mol%, preferably less than or equal to 4.5 mol%, particularly preferably less than or equal to 4 mol%, Nb 2 O 5 0 mol-% to 9 mol-%, Ta 2 O 5 0 mol-% to 7 mol-%, where Σ(A 2 O 5 ) greater than 0.2 mol-% to 9 mol-%, where A is an element which in oxides usually has the oxidation number V+, and includes or may include, for example, Nb and / or Ta or P and / or mixtures thereof.

[0053] It has been shown that a strong joint, for example a high-temperature stable and / or a mechanically high-strength joint, can be achieved by a sufficient addition of the oxides La 2 O 3 , Ta 2 O 5 and / or Nb 2 O 5, as well as possibly other oxides of composition A 2 O 5, within the limits mentioned above.

[0054] Here, A denotes an element that typically has an oxidation state of V+ in oxides. Therefore, it is possible that not all atoms "A" contained within the crystallizable or at least partially crystallized glass are in the same oxidation state.

[0055] The oxides La₂O₃, Nb₂O₅, and Ta₂O₅, as well as any other oxides A₂O₅ contained within the glass, are also referred to as "glass matrix-forming oxides" within the scope of this disclosure. This term, as used in this disclosure, means that such oxides initially remain in the glass matrix after the thermal treatment of the crystallizable glass, i.e., when the glass is at least partially crystallized. The term "glass matrix-forming oxides" thus differs from the more general term "glass-forming oxides." In particular, the oxides of MgO and CaO are not glass matrix-forming oxides within the scope of this disclosure, even though, for example, CaO is a common component of conventional glasses, such as soda-lime glass.In the glasses according to embodiments of the present disclosure, oxides such as CaO and MgO are incorporated into the crystal phases, thus they do not remain in the glass matrix and are therefore not glass matrix-forming oxides.

[0056] It is quite possible, however, that at least some of the glass matrix-forming oxides, for example La₂O₃, can be incorporated, at least partially, into crystalline phases during the further course of ceramicization. Nevertheless, a small residual amount of glassy phase usually remains, which is primarily formed by the glass matrix-forming oxides.

[0057] The formation of the joining compound according to the present disclosure with the oxides La₂O₃ and Nb₂O₅ and / or Ta₂O₅, and optionally further oxides A₂O₅ within the aforementioned limits, is advantageous because the at least partially crystallized glass is thus particularly advantageously shaped in such a way that glazing occurs during a heat treatment to produce the joint. In this way, a strong bond between the individual parts of the joining compound is particularly advantageously generated, and in particular, a strong bond between the at least partially crystallized glass and the joining partner is enabled. However, limiting the oxides forming the glass matrix within the aforementioned limits advantageously ensures that high temperature stability and / or high mechanical strength of the joint are simultaneously achieved.

[0058] Within the scope of this disclosure, the following definitions apply: Within the scope of this disclosure, crystallizable glass is understood to be glass that is amenable to crystallization, in particular controlled or at least controllable crystallization. Controlled crystallization is understood to mean that, by targeted temperature treatment, the crystallizable glass can be brought into a state in which the glass is at least partially crystallized, and wherein the crystallographic composition of the at least partially crystallized glass and / or its microstructure, i.e., the spatial arrangement and / or the size of the crystals and / or crystallites comprised by the at least partially crystallized glass, is preferably selectively adjusted.Preferably, a controlled crystallization can be used to obtain, for example, a microstructure in which the crystallites have a substantially uniform size, for example in the single-digit micrometer range, i.e., all crystallites have an equivalent diameter of about 1 µm to 3 µm.

[0059] Of course, other structures with larger or smaller crystallites are also possible.

[0060] If the at least partially crystallized glass comprises several different crystal phases, it is also possible that the average crystal or crystallite size within a crystal phase is relatively similar, but that there may be strong differences in crystallite size between the individual crystal phases.

[0061] In contrast to preferably controlled or controllable crystallization, spontaneous crystallization of a glass can occur, in which unexpected crystal phases, often also undesirable crystal phases, appear and in particular complete devitrification can occur.

[0062] Within the scope of this disclosure, a crystal aggregate or crystal association is understood to be an intergrowth of at least two crystals or crystallites. The crystals or crystallites may, in particular, be intergrown randomly. This means that the individual crystallites or crystals of an aggregate need not be intergrown along a preferred direction or along a specific crystal plane.

[0063] A crystal or crystallite is considered to have an acicular form if its dimensions in one direction are at least one order of magnitude larger than those in the other two spatial directions. In other words, an acicular crystal or crystallite can be needle-shaped, rod-shaped, or prism-shaped, with the lateral dimensions of the prismatic base being at least one order of magnitude smaller than the length of the crystal or crystallite. Such crystals or crystallites are also referred to as having a prismatic form.

[0064] The crystallites can also be plate-shaped, meaning they permeate the crystallized glass as small plates. In cross-sectional views, such a structure also appears as a rod, making differentiation difficult in individual cases. Within the context of this disclosure, a plate is understood to be a geometric shape in which the lateral dimension in one spatial direction of a Cartesian coordinate system (the thickness) is an order of magnitude smaller than the lateral dimensions (length, width) in the other two directions perpendicular to the first.

[0065] In the context of this disclosure, a radial arrangement of crystals or crystallites is understood to mean that acicular or plate-shaped crystals, for example, needle-shaped or prismatic crystals or crystallites, are arranged around a center such that one end points towards the same point and the other end points radially outwards in different directions. For example, the ends pointing towards the center may touch at the central point. However, this is not necessary. Such a configuration of crystal aggregates pointing radially outwards from a center exists, for example, in the form of a spherulitic configuration of a crystal aggregate. Such a spherulitic configuration is an approximately spherical or ellipsoidal shape of the crystal aggregate and may, in a two-dimensional representation, have an approximately circular form.In practice, however, the intergrowth of crystals and crystal aggregates within a microstructure often leads to deviations from the ideal spheroidal or circular shape of a spherulite. In particular, the crystals or crystallites forming the spherulite can exhibit different lengths and / or thicknesses.

[0066] Another embodiment of a radial arrangement is a fan-shaped structure in two-dimensional section. For example, it is possible that the formation of crystals or crystallites in a specific spatial direction within the microstructure is not possible. Here, too, the crystallites or crystals radiate outwards from a center, but only within a specific solid angle.

[0067] A rod-shaped or plate-shaped arrangement is understood to mean that the individual crystals or crystallites do not radiate outwards from a common center in different spatial directions, but are arranged randomly, for example, without a pronounced preferred direction. In particular, the crystallites or crystals can be interlocked with one another. Such a structure can also be compared, for example, to the construction of a "house of cards," in which the individual plates (like the cards of a house of cards) are arranged against one another and form a stable structure.

[0068] Within the scope of this disclosure, a crystallization nucleus is understood to be a starting point for crystallization. The crystallization nucleus promotes the attachment of atoms to form a crystalline lattice, for example, thermodynamically or kinetically. In particular, a crystallization nucleus can be a lattice defect and / or an arrangement of atoms. Interfaces can frequently be starting points for crystallization, or interfaces may contain such starting points for crystallization.

[0069] According to one embodiment of the joining compound, the crystallites include at least partially crystallization nuclei at the grain boundaries and / or at least partially enrichments comprising lanthanum, in particular comprising lanthanum compounds, are arranged at the grain boundaries of the crystallites.

[0070] Such a design of a joining joint is advantageous for enabling the formation of a particularly strong bond between at least partially crystallized glass and the joining partner. If the crystallites include crystal nuclei at least partially at the grain boundaries, this promotes the formation of the microstructure of the at least partially crystallized glass comprising crystal aggregates with, for example, radially radiating, rod-shaped, or plate-like arrangements, such as in the form of a house of cards.

[0071] This is also the case when enrichments comprising lanthanum, particularly lanthanum compounds, are located at least partially at the grain boundaries of the crystallites. The inventors hypothesize that enrichments of lanthanum, for example of lanthanum compounds, can act as effective nucleation sites.

[0072] According to a further embodiment of the joining process, the difference in the coefficients of thermal expansion between the joining partner and the at least partially crystallized glass is 5 × 10⁻⁶ K / K or less, preferably 3 × 10⁻⁶ K / K or less, and particularly preferably 1 × 10⁻⁶ K / K or less. Such a configuration of the joining process, in particular the matching of the coefficients of thermal expansion of the glass and the joining partner, has the advantageous effect of further improving the thermal and / or mechanical resistance of the resulting joining process.

[0073] The joint can withstand high operating temperatures. In particular, operating temperatures of 1000 °C and above are possible. It is assumed that the presence and described structure of the crystal aggregates mechanically stabilize the material, for example, by the crystal aggregates interlocking and interlocking with one another. If a residual glass phase is present, this can also be stabilized by the crystal aggregates and / or their structure, even if the residual glass phase were to soften due to temperature exposure.

[0074] The joint is also advantageously mechanically stable, particularly against vibration loads. These are measured in vibration tests according to ISO 16750-3 (version 2007-08-01), depending on the temperature. It is assumed that the crystal aggregates suppress the propagation of initial cracks in the material, thus preventing failure of a component with the joint even in the case of localized damage.

[0075] According to one embodiment of the disclosure, the joining connection can withstand operating temperatures of at least 1000 °C; preferably, the joining connection is vibration- and shock-resistant as measured according to ISO 16750-3.

[0076] In other words, the crystal aggregates appear to counteract the displacement of volume elements of the at least partially crystallized glass relative to one another during operation. This can be visualized as considering any two adjacent crystal aggregates containing volume elements. During operation, under mechanical stress, a force can act on the volume elements, for example, a shear force, which would displace them relative to each other. If the crystal aggregates have a suitable structure, particularly the aforementioned structure, they can interlock and thus suppress the displacement of the volume elements relative to each other purely mechanically.

[0077] According to a further embodiment of the joining connection, the crystal aggregates counteract the displacement of volume elements of the at least partially crystallized glass against each other in the operating state.

[0078] The measures mentioned above can also work together to be particularly advantageous.

[0079] Preferably, the joining connection is designed such that the surface of the at least partially crystallized glass is meniscus-free or has a neutral meniscus.

[0080] A meniscus-free surface, as used here, means that the surface is not convex. A convex surface of the at least partially crystallized glass can result, for example, if the glass is heated to create the joint and partially melts (so-called glazing), thereby wetting the joining partner particularly well, so that capillary forces cause the glass to rise at the interface. In this case, the meniscus is concave. If, on the other hand, there is only slight wetting, for example, with a very high viscosity glass, a convex meniscus can form. Ideally, however, the joint is designed so that the surface of the at least partially crystallized glass is meniscus-free, i.e., without any upward or downward curvature. In this case, it is also referred to as a neutral meniscus.

[0081] According to a further embodiment of the joining connection, an at least predominantly amorphous glass layer is arranged in the transition area between the surface of the joining partner and the surface of the at least partially crystallized glass, which preferably comprises less than 10 pores per cm³ and / or preferably has a thickness of 5 µm or less, particularly preferably 2 µm or less and most preferably 1 µm or less.

[0082] This design of the joint is advantageous because it allows for a particularly strong bond. In particular, low porosity at the interface between the at least partially crystallized glass and the joining partner advantageously leads to a further increase in the mechanical and / or thermal resistance of the joint. Pores at or near the interface can be the starting point for mechanical failure, especially when the joint is exposed to high temperatures.

[0083] Even the minimal thickness of an amorphous glass layer at the interface advantageously supports the formation of a joint that is, for example, highly resistant to thermal and / or mechanical stress. The formation of the glass layer means that a chemical bond exists between the joining partner and the glass. However, according to the present disclosure, it is particularly advantageous if the at least partially crystallized glass has a residual glass content of less than 10 vol%, preferably less than 5 vol%. In other words, the at least partially crystallized glass should have only a small residual glass content. This is because the thermal and / or mechanical stability of the joint results in particular from the formation of the crystalline phase(s).High thermal and / or mechanical resilience is advantageously ensured, in particular, when the amorphous glass layer has a small thickness of at most 5 µm or less, preferably 2 µm or less, and most preferably 1 µm or less.

[0084] According to one embodiment of the joining connection, the joining partner comprises a metal, in particular a metal from the group of steels, for example, normal steels, stainless steels, and high-temperature-resistant ferritic steels, which are also known under the brand name Thermax, for example, Thermax 4016, Thermax 4742, or Thermax 4762 or Crofer 22 APU or Crofer 22 H, or NiFe-based materials, for example, NiFe 45, NiFe 47, or nickel-plated pins, or known under the brand name Inconel, for example, Inconel 718 or X-750, or steels, for example, known under the designations CF25, Alloy 600, Alloy 601, Alloy 625, Alloy 690, SUS 310S, SUS 430, SUH 446, or SUS 316, or austenitic steels such as 1.4762. 1.4828 or 1.4841, Kanthal heating wire or a high-temperature stable ceramic compound, for example Forsterite, an aluminum oxide-based ceramic or a zirconium oxide-based ceramic, for example a ceramic comprising Y-stabilized zirconium oxide.

[0085] According to one embodiment, the joining compound has a helium leakage rate of less than 10⁻⁸ mbar * l / s and / or comprises, according to another embodiment, at least partially crystallized glass having a Young's modulus between 80 GPa and 200 GPa, preferably a Young's modulus between 100 GPa and 125 GPa. Such a design is advantageous because, while sufficient mechanical stiffness is achieved, the resulting joint is more elastic compared to, for example, conventional ceramics. This is advantageous under temperature cycling and therefore advantageously leads to a particularly temperature-stable joining compound.

[0086] The revelation further relates to a crystallizable or at least partially crystallized glass, comprising La 2 O 3 greater than 0.3 mol% to less than 5 mol%, preferably less than or equal to 4.5 mol%, particularly preferably less than or equal to 4 mol%, Nb 2 O 5 0 mol-% to 9 mol-%, Ta 2 O 5 0 mol-% to 7 mol-%, where Σ(A 2 O 5 ) greater than 0.2 mol-% to 9 mol-%, where A is an element which in oxides usually has the oxidation number V+, and may include, for example, Nb and / or Ta or P and / or mixtures thereof.

[0087] It has been shown that a firm bond between the glass and the joining partners can be achieved by a sufficient addition of the oxides La 2 O 3 , Ta 2 O 5 and / or Nb 2 O 5, i.e. within the limits mentioned above, as well as, if necessary, further oxides of composition A 2 O 5.

[0088] Here, A denotes an element that typically has an oxidation state of V+ in oxides. Therefore, it is possible that not all atoms "A" contained within the crystallizable or at least partially crystallized glass are in the same oxidation state.

[0089] The oxides La₂O₃, Nb₂O₅, and Ta₂O₅, as well as any other oxides A₂O₅ contained within the glass, are also referred to as "glass matrix-forming oxides" within the scope of this disclosure. This term, as used in this disclosure, means that such oxides initially remain in the glass matrix after the thermal treatment of the crystallizable glass, i.e., when the glass is at least partially crystallized. The term "glass matrix-forming oxides" thus differs from the more general term "glass-forming oxides." In particular, the oxides of MgO and CaO are not glass matrix-forming oxides within the scope of this disclosure, even though, for example, CaO is a common component of conventional glasses, such as soda-lime glass.In the glasses according to embodiments of the present disclosure, oxides such as CaO and MgO are incorporated into the crystal phases, thus they do not remain in the glass matrix and are therefore not glass matrix-forming oxides.

[0090] However, it is quite possible that one or more glass matrix-forming oxides are at least partially incorporated into crystal phases later in the ceramicization process, such as La₂O₃. Nevertheless, a residual glass component usually remains, which is formed by the so-called glass matrix-forming oxides.

[0091] The addition of the components La₂O₃, Ta₂O₅ and / or Nb₂O₅, as well as possibly further oxides A₂O₅, initially contributes to the high glass stability of the starting material. As already explained, these oxides are those which, after thermal treatment—that is, a thermal treatment by which the crystallizable glass can be transformed into at least a partially crystallized glass—remain, at least initially, in the glass matrix surrounding the crystallites and / or crystals.

[0092] The inventors assume that these components, if they transform at all, will only do so later in the thermal treatment and / or become incorporated into crystalline structural components. In particular, at least the component La₂O₃ can be at least partially incorporated into crystalline phases.

[0093] Surprisingly, it has been shown that the glassy microstructure component, which can include the oxides listed above, such as La 2 O 3 , Ta 2 O 5 and / or Nb 2 O 5 as well as possibly other oxides A 2 O 5 , ensures a strong bond with the joining partners, i.e. the materials and / or components to be joined, and yet does not impede high dimensional stability of the resulting joint at high temperatures, such as temperatures of 900°C or even 950°C or 1000°C or more.

[0094] Within the scope of this disclosure, a material and / or a component is designated as high-temperature resistant or high-temperature stable if it can be used at a temperature of 900°C and above, preferably 950°C and above, and particularly preferably 1000°C and above, and especially if it can be used at a temperature of 900°C and above, preferably 950°C and above, and particularly preferably 1000°C and above for 100 hours or more, preferably 500 hours or more, and particularly preferably 1000 hours. In particular, the material and / or the component can be designed to be stable against deformation at these temperatures over the aforementioned periods.

[0095] This high dimensional stability is attributed to a relatively early onset of crystallization. However, due to the glass matrix, this does not impede the strong bond between the joining partners. This is particularly surprising, as it was previously assumed that a strong, dense bond could only be achieved if crystallization occurred after sintering was complete; see, for example, Tulyaganov et al., Journal of Power Sources 242 (2013), 486-502.

[0096] Other components that may be contained within the glass and remain at least partially in the glass matrix after thermal treatment are Bi₂O₃ and / or P₂O₅. However, these components are detrimental with regard to the high temperature stability of the glass and the joint produced with this glass, which are addressed here. Therefore, according to one embodiment, the glass is advantageously free of oxides of Bi and / or P, except for unavoidable traces.

[0097] For the purposes of this disclosure, unavoidable traces of a component are defined as concentrations of that component which are 500 ppm or less. The unit "ppm" is based on weight.

[0098] According to a further embodiment, the glass is free of alkali oxides and / or boron, except for unavoidable traces. In particular, this means that, according to a particularly preferred embodiment of the invention, the glass comprises at most 500 ppm B₂O₃. The freedom of the glass from alkali oxides and / or B₂O₃ according to these embodiments is advantageous because the aforementioned components reduce the temperature resistance of the crystallizable or at least partially crystallized glass. Furthermore, these components, like certain alkalis, could potentially lead to the formation of low-expansion crystal phases, which are undesirable for the applications addressed here. Additionally, alkali contents are disadvantageous because they reduce electrical resistance.

[0099] The glass contains an oxide RO and it applies Σ(RO) less than or equal to 55 mol%, where R is an element which in oxides usually has the oxidation number II+, and in particular includes Ca, Mg or Zn and / or mixtures thereof.

[0100] In other words, RO comprises alkaline earth oxides as well as ZnO. According to a preferred embodiment of the disclosure, the glass is free of the alkaline earth oxides BaO and / or SrO except for unavoidable traces, in order to avoid interfering contact reactions of the glass with chromium-containing joining materials, such as chromium-containing steels.

[0101] The glass encompasses SiO2 30 mol% to 40 mol%, Al2O3 3 mol% to 12 mol%, CaO 32 mol% to 46 mol%, MgO 5 mol% to 15 mol%, ZnO 0 mol% to 10 mol%, and optionally ZrO 2 0 mol% to 4 mol%, preferably not more than 3 mol%, and / or TiO2 0 mol% to 4 mol%, preferably not more than 3 mol%, and / or MnO 2 0 mol-% to 5 mol-%.

[0102] Optionally, according to one embodiment, TiO₂, ZrO₂, and / or MnO₂ can be included in the glass. However, the content of these components in the glass is limited. In particular, TiO₂ and ZrO₂, which are known nucleating agents, are not required as nucleating agents in the crystallizable glass. Moreover, their presence can be detrimental, as, in the worst case, undesirable low-extensibility crystal phases can form for the present application.

[0103] According to another embodiment, the CaO content of the glass is between at least 35 mol% and at most 46 mol%, preferably between at least 35 mol% and less than 43.5 mol% and / or the MgO content of the glass is between 5 mol% and less than 13 mol%.

[0104] The limited CaO and / or MgO content of the glass is due to the fact that this further increases the stability of the crystallizable glass against spontaneous crystallization. CaO and MgO are components that are incorporated into the crystal phases formed by the thermal treatment of the crystallizable glass. As explained above, it is particularly important for the applications in question that crystal phases with a high coefficient of thermal expansion are obtained. To promote the predominantly obtained crystal phases with a high coefficient of thermal expansion, the CaO and MgO content of the glass is therefore preferably further limited as described above. This limitation serves in particular to prevent the formation of wollastonite, enstatite, or diopside.to prevent, at least as far as possible, or even to completely suppress, the formation of mixed crystals of these crystalline phases.

[0105] According to another embodiment, the glass is a crystallizable glass and has a transformation temperature of more than 720°C.

[0106] The transformation temperature of a glass is an important characteristic that reflects both its processing properties and its thermal stability. In particular, a high transformation temperature of the glass is associated with high dimensional stability.

[0107] Preferably, the crystallizable glass according to one embodiment therefore exhibits a particularly high dimensional stability, which is reflected in the specified high transformation or glass transition temperature Tg of 720°C or more.

[0108] According to a further embodiment, the linear coefficient of thermal expansion of the crystallizable glass is greater than 8 × 10⁻⁶ K / K in a temperature range of 20°C to 300°C and preferably greater than 9 × 10⁻⁶ K / K in a temperature range of 20°C to 700°C. In this way, it is advantageously possible to achieve a good match between the glassy material and the linear coefficient of thermal expansion of the materials to be joined, for example, highly refractory materials such as Y-stabilized ZrO₂ and / or alloys, even before the completion of the thermal treatment for producing the preferably hermetically sealed connection.

[0109] The transformation temperature Tg is determined by the intersection point of the tangents to the two branches of the expansion curve when measured at a heating rate of 5 K / min. This corresponds to a measurement according to ISO 7884-8 or DIN 52324.

[0110] The softening temperature of a glass, also abbreviated as "Ew" within the context of the present temperature, denotes the temperature at which the viscosity of the glass has a value of 1 0 7.6< dPa*s.

[0111] The coefficient of thermal expansion specified in this disclosure is the linear coefficient of thermal expansion. If the linear coefficient of thermal expansion is specified for a crystallizable glass, it is the nominal mean coefficient of linear thermal expansion according to ISO 7991, which is determined by static measurement (using a push-rod dilatometer). The linear coefficient of thermal expansion for a glass that is at least partially crystallized is determined dilatometrically.

[0112] Within the scope of this disclosure, the linear coefficient of thermal expansion is also referred to as α. For example, a(20-700) or α 20-700 denotes the linear coefficient of thermal expansion in the temperature range from 20°C to 700°C.

[0113] According to a further embodiment of the disclosure, the glass is at least partially crystallized and has a linear coefficient of thermal expansion in the temperature range from 20°C to 700°C of more than 9 * 10 -6< / K, preferably more than 10 * 10 -6< / K, wherein the linear coefficient of thermal expansion of the at least partially crystallized glass in the temperature range from 20°C to 1000°C is particularly preferably more than 9 * 10 -6< / K, preferably more than 9.5 * 10 -6< / K.

[0114] According to embodiments of the disclosure, the glass is designed such that not only preferably hermetically sealed and / or electrically insulating connections can be produced. In particular, according to embodiments, preferably hermetically sealed and / or electrically insulating connections can also be produced that continue to provide sufficient electrical insulation even at high temperatures.

[0115] Connections such as metal-glass connections are described as fluid-tight if they seal properly, meaning they are tight against the escape or passage of fluid media and preferably essentially completely (hermetically) sealed. The tightness can be determined by a leak test, usually using a helium leak tester. Helium leak rates of less than 1 x 10⁻⁸ mbar / l / s at room temperature indicate that an essentially completely hermetic seal is present. This measurement can preferably be performed under a pressure of one bar.

[0116] According to these embodiments, the glass is in the form of crystallizable glass, wherein the temperature of the crystallizable glass for the specific electrical resistance of 10 8< Ω * cm, preferably determined according to DIN 52326, tk 100, is 500°C or more.

[0117] The crystallizable or at least partially crystallizable glass comprises SiO2 and CaO and MgO and Al2O3, and optionally ZnO.

[0118] In the SiO₂-Al₂O₃-CaO-MgO system, crystal phases with high coefficients of thermal expansion are possible. These include, for example, mixed crystals from the family of CaO-rich calcium magnesium silicates, such as ekermanite and / or merwinite, which, for instance, also form gehlenite and / or augut as mixed crystals with Al₂O₃. If the glass also contains ZnO, hardystonite can also form as a mixed crystal.

[0119] According to one embodiment, the glass is present as at least partially crystallized glass and comprises crystallites of preferably CaO-rich calcium magnesium silicates, in particular of CaO-rich calcium magnesium island silicates and / or group silicates. Island silicates are those silicates in which the SiO₄ tetrahedra encompassed by the silicates are present individually, i.e., not linked together. Group silicates are silicates in which two SiO₄ tetrahedra are linked together via a common bridging oxygen, such that Si₂O₇ assemblies are present as the silicate structural unit. Preferably, the at least partially crystallized glass can comprise the island silicate merwinite Ca₃Mg(SiO₄)₂ and / or a mixed crystal with a merwinite structure.Furthermore, the at least partially crystallized glass can alternatively or additionally comprise group silicate crystal phases with a melilite structure, such as ekermanite Ca₂MgSi₂O₇ or gehlenite Ca₂Al[AlSiO₇], or mixed crystals thereof. According to one embodiment, the at least partially crystallized glass can also comprise crystal phases with an augite structure.

[0120] Whenever a mixed crystal is mentioned in this disclosure, it refers to a crystal that does not correspond to a stoichiometric compound. For example, when an "Åkermanite mixed crystal" is mentioned, this refers to a crystal that does not have the stoichiometric composition Ca₂MgSi₂O₇. For instance, the mixed crystal may contain more Ca than its stoichiometric composition would suggest, or Zn may be incorporated instead of Ca. However, the mixed crystal crystallizes in a crystal structure that largely corresponds to that of Åkermanite, i.e., except for minor deviations with regard to, for example, the lattice constants.

[0121] According to one embodiment, the glass is present as at least partially crystallized glass and comprises crystallites of preferably CaO-rich calcium magnesium silicates, in particular of CaO-rich calcium magnesium nesosilicates and / or group silicates, such as merwinite and / or a mixed crystal with merwinite structure and alternatively or additionally a crystal phase with melilite structure, such as ekermanite Ca 2 MgSi 2 O 7 and / or gehlenite Ca 2 Al[AlSiO 7 ] and / or mixed crystals thereof, and / or crystal phases with augite structure.

[0122] The present disclosure also relates to a joining connection comprising at least partially crystallized glass, wherein the glass is at least partially crystallized glass according to embodiments of the present disclosure or is made or can be made from a crystallizable glass according to embodiments of the present disclosure.

[0123] For the purposes of this disclosure, a joining partner is understood to be a material or component which is usually assembled or joined with another material or component to form a preferably hermetically sealed composite component. If there are several joining partners to be joined, they may have the same or different compositions.

[0124] Within the context of this disclosure, the connection is also referred to as a joining compound or joining connection.

[0125] The disclosure also relates to a product. The product is, in particular, a holding element and / or an insulating element and / or an additive structure comprising at least partially crystallized glass according to embodiments of the present disclosure.

[0126] Preferably, the product is producible from a sintered body comprising a crystallizable glass according to embodiments of the present disclosure. Preferably, the sintered body comprises the crystallizable glass as a glass powder. Most preferably, the glass powder comprises powder grains with grain surfaces.

[0127] Furthermore, the disclosure relates to the use of an joining connection according to embodiments of the present disclosure. In particular, the connection can be used in a sensor, such as an exhaust gas sensor, as in an exhaust system of an automobile, a pressure sensor, a particle sensor, such as a soot particle sensor and / or a temperature sensor and / or a NO x sensor and / or an oxygen sensor, and / or in a feedthrough for a compressor and / or an electric compressor and / or as an electrical current feedthrough in an exhaust element and / or in a fuel cell and / or in a feedthrough for a chemical reactor. Examples

[0128] The crystallizable or at least partially crystallizable glass disclosed herein, as well as its use, will be explained in more detail below with reference to examples.

[0129] The following table shows examples of the composition of crystallizable or at least partially crystallized glasses. The compositions are given in mol%. The characteristic temperatures are those commonly used to describe the melting behavior of ash, such as softening temperature (abbreviated: softening), sintering temperature (abbreviated: sintering), spherical temperature (abbreviated: spherical), hemispherical temperature (abbreviated: hemispherical), and flow temperature, as determined using a heating microscope (abbreviated: HMS). These temperatures are determined according to or in accordance with DIN 51730. The coefficient of thermal expansion α is given in units of 10⁻⁶ / K. Table 1 Compositions of glasses according to embodiments Example No. 1 2 3 4 5 6 7 8 SiO2 36 34 36 34 34 38 35 35 Al2O3 7 6 7 6 9 5 7,7 7 B2O3 TiO2 MnO 2 ZrO 2 2 P2O5 Bi 2 O 3 La 2 O 3 2 2 2 4 1 2 2,6 2,2 Nb 2 O 5 6 3 2 1 0,2 0,6 Ta 2 O 5 4 2 0,3 0,6 Y2O3 R2O ZnO 6 4 2 3 3,3 MgO 9 10 10 10 11 10 12,2 10,3 CaO 38 38 42 40 43 42 39 41 SrO BaO sum 100 100 100 100 100 100 100 100 Σ(RO) 47 54 52 54 54 54 54,2 54,6 CaO+MgO 47 48 52 50 54 52 51,2 51,3 Σ(R 2 O 3 +A 2 O 5 ) 8 6 5 6 3 3 3,1 3,4 Σ(A 2 O 5 ) 6 4 3 2 2 1 0,5 1,2 CaO / MgO 4,22 3,80 4,20 4,00 3,91 4,20 3,20 3,98 Temperatures [°C] EHM: Sintering 767 772 772 770 762 765 770 EHM: Soften. 890 925 922 811 Sphere. 1282 1259 1304 hemisphere 1198 1289 1265 1320 1298 1340 1320 Crystallizable glass α (20;300°C) 8,28 8,33 8,8 8,81 8,46 8,72 8,47 8,64 α (20;700°C) 9,24 9,43 9,81 9,8 9,42 9,88 9,63 9,65 Tg[°C] 752 743 754 737 753 741 739 734 Ew[°C] 877 883 873 878 875 Density [g / cm³] 3,43 3,77 3,27 3,64 3,13 3,22 3,28 3,32 tk 100[°C] 572 596 588 604 593 611 606 E-modulus [GPa] 107 107 105 107 106 Crystallized glass Crystallization took place at 1000°C / 20 min α (20;700°C) 8,7 9,3 10,9 9,9 9,3 9,6 9,96 9,3 α (20;1000°C) 9,4 9,55 11,1 10,15 9,6 9,66 10,23 9,7 Crystallization This was done at 1040°C / 200 min α (20;700°C) 10,53 9,2 10,3 9,7 9,7 10,2 9,25 10,15 α (20;1000°C) 10,25 9,55 10,75 10 9,65 10,35 9,15 10,2 Table 1 (continued) Example No. 9 10 11 12 13 14 15 16 SiO2 33,2 34,5 35 36 35,3 36,8 36,4 35 Al2O3 10 6,6 6 8 7,7 6,6 8 6,6 B2O3 TiO2 2 MnO 2 2 ZrO 2 1,2 0,3 P2O5 Bi 2 O 3 La 2 O 3 1,7 2,2 3 2,4 3 2,6 2,8 2,4 Nb 2 O 5 1,2 1,6 2 0,8 0,3 0,6 0,6 Ta 2 O 5 0,5 0,1 0,3 0,4 0,4 Y2O3 R2O ZnO 3 2 1 1 1,4 6,4 MgO 8,2 10 10 11,8 10 10,8 11,8 10,6 CaO 42,2 43 42 38,5 41 42,6 38,6 38 SrO BaO sum 100 100 100 100 100 100 100 100 Σ(RO) 53,4 55 52 51,3 52 53,4 51,8 55 CaO+MgO 50,4 53 52 50,3 51 53,4 50,4 48,6 Σ(R 2 O 3 +A 2 O 5 ) 3,4 3,9 5 2,7 3,8 2,9 3,8 3,4 Σ(A 2 O 5 ) 1,7 1.7 2 0,3 0,8 0,3 1 1 CaO / MgO 5,15 4,30 4,20 3,26 4,10 3,94 3,27 3,58 Temperatures [°C] EHM: Sintering 770 762 760 761 786 EHM: Soften. 904 Sphere. 1308 1270 1313 1290 1309 hemisphere 1320 1279 1318 1300 1316 Crystallizable glass α (20;300°C) 8,4 9,05 8,94 8,5 8,7 8,9 8,53 8,6 α (20;700°C) 9,4 10 10,04 9,53 9,62 9,84 9,57 9,8 T g [°C] 749 749 747 746 754 757 747 726 Ew[°C] 880 875 880 878 891 900 884 862 V a [°C] 1059 Density [g / cm³] 3,26 3,28 3,35 3,23 3,29 3,2 3,29 3,37 tk 100[°C] 616 598 590 606 607 609 609 607 E-modulus [GPa] 106 106 107 107 Crystallized glass Crystallization took place at 1000°C / 20 min α (20;700°C) 10,6 10,75 10,55 10,7 10,0 10,2 α (20;1000°C) 11,1 11.1 11,1 11 10,3 10,2 Crystallization took place at 1020°C / 20 min α (20;700°C) 10,15 α (20;1000°C) 10,1 Crystallization took place at 1040°C / 200 min α (20;700°C) 9,5 10 9,55 10,3 10,4 9,4 α (20;1000°C) 9.65 9,7 9,7 10,1 10,3 9,6 Table 1 (continued) Example No. 17 18 SiO2 35,6 35,5 Al2O3 8 6 B2O3 TiO2 MnO 2 ZrO 2 P2O5 Bi 2 O 3 La 2 O 3 3,2 3,6 Nb 2 O 5 0,75 0,8 Ta 2 O 5 0,45 0,3 Y2O3 R2O ZnO 2 4 MgO 12 12,8 CaO 38 37 SrO BaO sum 100 100 Σ(RO) 52 53,8 CaO+MgO 50 49,8 Σ(R 2 O 3 +A 2 O 5 ) 4,4 4,7 Σ(A 2 O 5 ) 1,2 1,1 CaO / MgO 3,178 Temperatures [°C] EHM: Sintering 786 EHM: Soften. Sphere. hemisphere 1319 Crystallizable glass α (20;300°C) 8,5 8,69 α (20;700°C) 9,58 9,88 T g [°C] 746 736 Ew[°C] 882 870 Density [g / cm³] 3,35 3,43 tk 100[°C] E-modulus [GPa] Crystallized glass Crystallization took place at 1000°C / 20 min α (20;700°C) 9,3 Example No. 17 18 a (20;1000°C) 9,7 Crystallization took place at 1040°C / 200 min a (20;700°C) 9,7 9,8 α (20;1000°C) 9,9 10,3

[0130] Table 2 below lists comparative examples of crystallizable or at least partially crystallized glasses. Table 2 Compositions of comparative examples Comparative example 1 2 3 4 5 6 SiO2 38,7 30 37 32 32 31,5 Al2O3 1,6 0,3 7 5 1,5 1,5 B2O3 8,9 1,2 8 8,5 TiO2 MnO 2 ZrO 2 4 3 P2O5 0,9 Bi 2 O 3 0,4 La 2 O 3 2 5 Nb 2 O 5 Ta 2 O 5 1 Y2O3 3,4 1,6 4 4,5 R2O ZnO 2 MgO 6,7 19,3 10 11 33 34 CaO 36,7 46,3 40 44 21 21,5 SrO BaO sum 100 100 100 100 100 100 Σ(RO) 43,4 65,6 50 57 54 55,5 CaO+MgO 43,4 65,6 50 55 54 55,5 Σ(R 2 O 3 +A 2 O 5 ) 3,4 2,9 6 6 4,5 0 Σ(A 2 O 5 ) 0 0 0 1 0 0 CaO / MgO 5,48 2,40 4,0 4,0 0,64 0,63 Characteristic temperatures [°C] EHM: Sintering 753 744 684 EHM: Soften. 797 1386 784 778 Sphere. 898 879 821 hemisphere 1111* 1389 1139* 1126* Comparative example 1 2 3 4 5 6 Crystallizable glass a(20;300°C) 8,36 8,73 8,81 9,51 α(20;700°C) T g [°C] 692 783 696 616 Ew[°C] Density [g / cm³] tk 100[°C] E-modulus [GPa] Crystallized glass Crystallization took place at 1000°C / 20 min α (20;700°C) α (20;1000°C) Crystallization took place at 1040°C / 200 min α (20;700°C) α (20;1000°C)

[0131] In comparison examples 1, 5 and 6, the glass flowed at a flow temperature of 1128°C (comparison example 1), 1166°C (comparison example 5) and 1147°C (comparison example 6).

[0132] In comparison examples 2, 3, and 4, no glass could be obtained. Instead, these compositions crystallized uncontrollably upon cooling after melting.

[0133] The glasses according to embodiments of the present disclosure are obtained in a glassy state from a melting process. A high cooling rate is not required during casting. Among other things, castings of at least 30 cm³ were produced, i.e., with a weight of more than 100 g. This is all the more surprising since, in the technical literature, a glassy solidification is described as possible only for ribbons and on a small scale.

[0134] Crystallized or at least partially crystallized glasses according to the present disclosure exhibit particularly advantageous dimensional stability. This can be demonstrated by the fact that the dimensional deviation between a sintered body comprising a crystallizable glass according to embodiments of the present disclosure and the molded body comprising at least partially crystallized glass, which is obtained from the sintered body by a temperature treatment for crystallization, is very small, namely a length deviation only in the single-digit percentage range, as shown by the measurement data listed in the following table. To determine these data, pressed bodies with a mean lateral dimension, here a mean diameter, of approximately 10-12 mm were produced. After sintering, the sintered bodies thus obtained were heated in a muffle furnace at a heating rate of 4 K / minute to 1200°C.The temperature of 1200°C was maintained for 10 minutes. Cooling then took place. After cooling, the mean lateral dimension, in this case the mean diameter, was determined again. Subsequently, the relative deviation of the mean lateral dimension before and after tempering at 1200°C was determined. Table 3 Changes in the mean lateral dimension of sintered bodies during crystallization Example No. Mean lateral dimension [mm] Relative deviation [%] Before tempering After tempering 1 11,02 11,09 0,64 2 11,33 11,44 0,97 3 11,06 11,79 6,60 4 10,98 10,97 0,03 5 10,95 11,31 3,32 6 10,88 11,38 4,66 7 10,81 11,00 1,76 8 10,75 10,79 0,40 9 11,07 11,16 0,87 10 10,79 10,83 0,36 11 10,75 11,25 4,65 12 10,98 11,30 2,85 13 10,93 11,39 4,27 14 10,69 10,76 0,59 15 10,81 11,16 3,24 Comparative example 1 11,93 melted Not determinable Comparative example 5 11,26 14,8 31,45

[0135] The demonstrated high dimensional stability of molded parts, such as pressed or sintered components, which initially comprise crystallizable glass and are transformed into molded parts comprising at least partially crystallized glass through heat treatment, means that, for example, reliable creepage distance extension in a feedthrough can now be implemented particularly advantageously. In particular, molded parts do not round off during heat treatment. The resistance to urea, especially at concentrations such as those used in AdBlue for SCR catalysts, and to the substances formed from it, is very good, thus enabling the continuous, reliable use of the joints described here in exhaust systems with exhaust gas purification systems. Figures

[0136] The embodiments disclosed herein are further explained below with reference to figures.

[0137] They show Fig. 1 shows a cross-sectional view through a first embodiment of the joining connections disclosed herein, in which the section plane is along the plane AA. Figure 1a approximately through the middle of the joint, Fig. 1a a top view of the Figure 1 The first embodiment is shown in cross-section, Fig. 2 a cross-sectional view through a second embodiment of the joining connections disclosed herein, in which the section plane is approximately as in Figures 1 and 1aas shown through the center of this joining joint, Fig. 2a a top view of a creepage extension of the first disclosed embodiment, on which a trace of a graphite or pencil can be seen, Fig. 2b a top view of a creepage extension of the first disclosed embodiment, on which a trace of a graphite or pencil can be seen after it has been at least partially removed with a cellulose cloth by a lateral wiping motion, Fig. 2c a top view of a creepage extension of the first disclosed embodiment, on which a trace of a graphite or pencil can be seen after it has been at least partially removed with a cellulose cloth by a lateral wiping motion, Fig. 3 a cross-sectional view through a third embodiment of the joining joints disclosed herein, in which the cutting plane is approximately as in Figures 1 and 1aThe plane of the section runs through the center of this joining connection, Fig. 4 shows a cross-sectional view through a fourth embodiment of the joining connections disclosed herein, in which the section plane runs approximately as in Figures 1 and 1a The plane of the section runs through the center of the joint, Fig. 5 shows a cross-sectional view through a fifth embodiment of the joints disclosed herein, in which the section plane runs approximately as in Figures 1 and 1a Figure 6 shows a cross-sectional view through a sixth embodiment of the joints disclosed herein, in which the section plane runs approximately through the center of the joint, Figures 7 to 10 show scanning microscopic images of at least partially crystallized glasses according to embodiments of the present disclosure, and Figure 11 shows a scanning microscopic image of a joint according to an embodiment of the present disclosure. Detailed description of preferred embodiments

[0138] In the following detailed description of embodiments disclosed herein, their components are not shown to scale for better understanding, and identical reference numerals denote identical or functionally corresponding components of the respective embodiments.

[0139] Figure 1 shows a cross-sectional view through a first embodiment of a joining connection 5 disclosed herein, in which the section plane is along the plane AA. Figure 1a approximately through the middle of the joint 5, and includes the center line M.

[0140] This joining connection 5 comprises an electrically insulating component 53 and at least two joining partners 51, 52. The joining partner 51, without limitation of generality, is hollow cylindrical in the embodiments disclosed herein and comprises a metal or a ceramic material, as will be explained in more detail below. The joining partner 52 can also consist of a metal, as will be described in more detail below, and can, for example, be part of an electrical or electronic feedthrough and thus, when used as intended, part of an electrical or electronic connection.

[0141] At least one of the joining partners 51, 52 is electrically insulated from at least one other joining partner 51, 52 by an electrically insulating component 53.

[0142] This component 53 can comprise or consist of the crystallizable or partially crystallized glass disclosed herein.

[0143] The insulating component 53 has a section 54 which extends between the joining partners 51, 52, connecting to them and preferably glazed onto them. Glazed onto the joining partner, as defined in this disclosure, means that the crystallizable or partially crystallized glasses disclosed herein form an amorphous or glassy layer on their surface during thermal processing, which can virtually melt onto the material of the respective joining partner and is then referred to as glazed onto the joining partner in this fused state.

[0144] The upper surface O of the insulating element is in Figure 1Section 54 is shown delimited by a dashed line L, which merely schematically depicts the course of the upper surface O without structure S, and thus without creep distance extension, for comparison with a joint with structure S and therefore with creep distance extension. Without structure S, the upper surface would form a flat surface, on which menisci might form at the respective joining partners.

[0145] However, in the embodiments disclosed here, a structure S, in particular a protrusion formed by section 55, is arranged on this surface of section 54 of the electrically insulating component 53, which extends between the joining partners.

[0146] Through this section 55, which forms the structure S, a distance on the surface of the insulating component 53 from the inner joining partner 52 to the outer joining partner 51 can be extended and, together with the structure S, thus the creepage distance extension can be increased by up to seven times or even more.

[0147] As a result, low-resistance deposits on the respective surface can only contribute to a much weaker extent to reducing the electrical resistance between the joining partners 51 and 52.

[0148] In the case of droplet- and / or surface film-forming deposits, it can be very advantageous if the structure S has edges with a radius of curvature Rv of less than one-tenth of a millimeter, preferably less than one-twentieth of a millimeter and more than 10 µm. In this case, it regularly occurs, often also under the influence of gravity, that a surface film or a coating with droplets does not extend over this edge with the radius of curvature Rv, and thus a continuous surface coating cannot form.

[0149] As an alternative to the raised section shown in the present embodiments, the structure S can also form a recess which then projects into the insulating component 53. In any case, however, the direct path from the at least one joining partner to the at least one other joining partner along the surface is lengthened compared to a surface without this structure S. Here, the direct path is understood to be the shortest path along the surface, firstly without the structure S and secondly, according to the invention, with the structure S, from one joining partner to the other.

[0150] Preferably, the structure S completely surrounds at least one joining partner, in this case the joining partner 52, as a ring-shaped structure, as can be clearly seen from the example shown. Figure 1aThis is evident. In the context of the present disclosure, the statement "completely surrounded" does not mean that a complete three-dimensional enclosure is required, although this is also possible in principle. A complete enclosure, as defined in the present disclosure, is already present if a complete ring-shaped enclosure is achieved, in particular one that provides a complete seal.

[0151] The structure S can be formed in one piece and of the same material as section 54 of the insulating component 53, which extends between the joining partners 51, 52, is connected to each of them and preferably glazed onto each of them.

[0152] Preferably, the material of the insulating component 53 comprises at least a partially crystallized glass, as described in more detail elsewhere in the present disclosure.

[0153] In this case, the insulating component 53 can be formed together with the structure S in a single thermal processing operation and, in particular, their degree of crystallinity can be adjusted.

[0154] Advantageously, the crystallizable glass disclosed herein forms, during thermal processing, particularly during tempering, an at least predominantly amorphous glass layer in the transition zone between the surface of the joining partner and the surface of the at least partially crystallized glass. This layer is subsequently permanently arranged at this location and preferably comprises fewer than 10 pores per cm³ and / or preferably has a thickness of 5 µm or less, particularly preferably 2 µm or less, and most preferably 1 µm or less. This results in a hermetic connection between the joining partners 51, 52 and the insulating component 53.

[0155] In a preferred embodiment, the structure comprises crystallizable or at least partially crystallized glass and has at least a predominantly amorphous boundary layer, in particular a glass layer, on the surface of the structure, which has essentially no open pores and in particular comprises less than 10 pores / cm 3<, which has a thickness of 5 µm or less, preferably 2 µm or less and most preferably 1 µm or less.

[0156] In this at least predominantly amorphous boundary layer, which depending on the embodiment has a thickness of 5 µm or less, preferably 2 µm or less and most preferably 1 µm or less, the proportion of the amorphous or glassy phase, measured in weight percent, is higher than the proportion of all the respective crystalline phases combined, also measured in weight percent.

[0157] It is quite possible, however, that at least some of the glass matrix-forming oxides, for example La₂O₃, can be incorporated, at least partially, into crystalline phases during the further course of ceramicization. Nevertheless, a small residual amount of glassy phase usually remains, which is formed primarily by the glass matrix-forming oxides and constitutes the aforementioned amorphous interfaces.

[0158] To determine whether an embodiment disclosed herein exists, the inventors have developed a test.

[0159] If one writes a line St, as shown in Figures 2a to 2c, on the surface of structure S or surface O, for example with a graphite pencil of hardness HB, which is held perpendicular to the surface of structure S and pressed down with approximately 100 mN, this line St is created as shown in Figures 2a to 2c. Figure 2a depicted.

[0160] Wiping parallel to the surface of structure S or surface O with a cellulose wipe, for example a Zewa brand, and applying a pressure of approximately 100 mN, results in very significant abrasion of the components disclosed here, which comprise crystallizable glass or partially crystallized glass. This is because the graphite of the graphite or pencil cannot adhere to the pores of the otherwise smooth surface. Typically, this greatly reduces the contrast between the line St and the surface of structure S or surface O, for example to a value of less than 50%, or, depending on the specified contrast, to less than 0.5.

[0161] However, if one wipes parallel to the surface of structure S or surface O with a cellulose wipe, for example a Zewa brand, and applies a pressure of approximately 100 mN, only minimal material removal occurs on components made of, for example, zirconium oxide, because the graphite from the graphite or pencil can remain in the pores of the ceramic surface. Typically, the contrast between the line St and the surface of structure S or surface O is only slightly reduced, for example to a value of more than 50% or, depending on the contrast specification, to more than 0.5.

[0162] In other embodiments, as shown only by way of example in the Figures 3 and 4As shown, the structure is not materially identical to section 54 of the insulating component 53, which extends between the joining partners 51, 52, is connected to it, and preferably glazed onto it. The structure S can then comprise or consist of a high-temperature-stable ceramic compound, for example, forsterite, an aluminum oxide-based ceramic, or a zirconium oxide-based ceramic, for example, a ceramic comprising Y-stabilized zirconium oxide. If the structure S is not formed from material according to the invention, the pencil test cannot be successfully performed.

[0163] Figure 2 shows a cross-sectional view through a second embodiment of the joining connections disclosed herein, in which the section plane is approximately as in Figures 1 and 1a represented by the center of this joint.

[0164] In this embodiment, the structure S comprises a reinforcement 56, which contains or consists of a metal foil, a metal sheet, or a metal-comprising fabric, braid, or knitted fabric, wherein the metal preferably consists of or comprises steel. This substantially ring-shaped reinforcement 56 is preferably held in further insulating components 57, 58, 59, which, being designed as sintered parts, can accommodate the reinforcement 56 and can be bonded to it after thermal treatment. The material of the substantially ring-shaped components 57, 58, and 59 can consist of the crystallizable glass disclosed herein.

[0165] Fig. 3 shows a cross-sectional view through a third embodiment of the joining connections disclosed herein, in which the section plane is approximately as in Figures 1 and 1a represented by the center of this joint,

[0166] In this embodiment, the structure S is not materially identical to section 54 of the insulating component 53, which extends between the joining partners 51, 52, is connected to it, and preferably glazed onto it. The structure S comprises or consists of a high-temperature-stable ceramic material, for example, forsterite, an aluminum oxide-based ceramic, or a zirconium oxide-based ceramic, for example, a ceramic comprising Y-stabilized zirconium oxide.

[0167] As from Figure 3As can be clearly seen, the structure S projects into the insulating component 53 and is surrounded by it in such a way that, during thermal processing, glass formation preferably occurs on the projecting area of ​​the structure S. The structure S is arranged approximately centrally in a radial direction on the section 54 of the insulating component 53 and preferably projects at least partially into it. This radial direction is Figure 3 represented by an arrow R.

[0168] Fig. 4 shows a cross-sectional view through a fourth embodiment of the joining connections disclosed herein, in which the section plane is approximately as in Figures 1 and 1a represented by the center of the joint.

[0169] This further schematic and not-to-scale illustration of the joint 5 differs from those in the Figs. 1 to 8The illustrated joining connections 5 are modified by the design of the structure S, which forms the creepage distance extension 55. This structure comprises, in addition to the material of section 54, a secondary material. This secondary material is also an insulating material, but differs from the material of section 54. In this embodiment, the material of section 54 is designed as a crystallizable or at least partially crystallized glass, as will be described in more detail later, wherein the secondary material has a different chemical and / or crystallographic composition. That is, the secondary material differs from the material of section 54 in that it has a different chemical composition and / or a different crystal content. In particular, the secondary material can be made of or comprise ZrO₂.It has been shown that particularly dimensionally and temperature-stable structures S can be used to extend creepage distances when between 5 wt.% and 25 wt.% of a secondary material, preferably ZrO₂, is added. A content of 10–15 wt.% is particularly preferred.

[0170] Fig. 5 Figure 1 shows a highly schematic embodiment of a joining connection 5 according to a fifth embodiment. The outer side wall 552 of section 55 has a slightly bent or curved shape, i.e., it is not perfectly flat. In contrast, the inner side wall 553 of section 55 is flat. As one Fig. 5 As can be seen, the flatness of side wall 552 differs from the flatness of side wall 553. Side wall 552 is shown somewhat distorted here, as such a significant deviation from a flat surface for the side walls does not occur in reality.

[0171] Fig. 6Figure 6 shows the case of a joint 5 according to a further, sixth embodiment, in which both the inner and outer side walls 552 and 553 are not perfectly flat. However, the flatness is almost identical for both side walls 552 and 553. Here again, significant distortion has been introduced to illustrate the effect of a not perfectly flat side wall. Generally, much smaller deviations from a flat side wall are achieved.

[0172] Fig. 7 Figure 1 shows a first scanning microscopic image of an at least partially crystallized glass according to an embodiment of the disclosure. The at least partially crystallized glass comprises crystal aggregates 1, which are formed from a plurality of crystallites, wherein these crystallites are preferably needle-shaped. In the Fig. 1A crystal aggregate 1 was designated as such by way of example. Furthermore, crystallites 21 are recognizable at grain boundaries and were designated by way of example, as were acicular crystallites 22.

[0173] Fig. 8Figure 1 shows a second scanning micrograph of at least partially crystallized glass according to a further embodiment of the disclosure. Here, too, the at least partially crystallized glass comprises crystal aggregates formed from a multitude of crystallites, which are preferably needle-shaped. Furthermore, pores are partially arranged between the individual crystallites, and the at least partially crystallized glass also comprises a residual glass phase arranged between the crystallites. The crystallites 2, which here form a star-shaped crystal aggregate, are designated by way of example. Also visible is the residual glass phase 3, which has a gray color in the scanning micrograph, as well as the pore 4 (shown in black), which is designated by way of example.

[0174] Fig. 9Figure 1 is a third scanning micrograph of at least partially crystallized glass according to a further embodiment of the disclosure. Here, too, the crystal aggregates are visible. The crystallites are so finely formed that they are hardly recognizable as such at the selected resolution. In this way, a very dense, fine structure is achieved. Reference can be made here to the very fine crystals 22 described above.

[0175] Fig. 10 This is a further scanning microscope image of a further, at least partially crystallized glass according to an embodiment of the disclosure. The crystallites 23 encompassed by the crystal aggregates of the at least partially crystallized glass are, in contrast to the crystallites of the [unclear text], [unclear text]. Fig. 9The partially crystallized glass shown is not so finely formed; rather, its rod-like or possibly plate-like shape is recognizable. The crystallites 23 are arranged interlocking with one another, similar to a "house of cards" structure.

[0176] Fig. 11 Figure 1 shows a scanning micrograph of a joining joint according to an embodiment of the disclosure. At the interface between the joining partner arranged on the left of the image and the at least partially crystallized glass, a very thin boundary layer is formed, comprising fewer than 10 pores / cm³. This layer is at least predominantly amorphous and has a thickness of 5 µm or less, preferably 2 µm or less, and most preferably 1 µm or less.

[0177] The following findings apply to all of the embodiments disclosed above.

[0178] The embodiments described above have only been described with respect to two joining partners. However, it is within the scope of the present disclosure that three or more joining partners can also be held together in a joining connection by the insulating component, analogous to the one disclosed here.

[0179] With the joining connections disclosed herein, a multiple extension of the creep distance is possible, with an extension factor of more than 7 being achieved.

[0180] The combination of water resistance in electrocorrosion-prone environments and the high dimensional stability of the joints revealed here is also advantageous.

[0181] The sufficiently high electrical resistance allows the use of the crystallizable glass as a creepage distance extension even under condensation of water (generally) or even of coolant (e.g. as a feedthrough in an electric compressor),

[0182] One advantage over ceramics is the closed porosity of the structure S, and thus of the excess material.

[0183] Continuous operation applications include the provision of power or electricity supply for heating elements (primarily for use, for example, in heated catalyst elements, sensors in the exhaust system, and generally as a feedthrough for electric compressors, primarily in automotive applications).

[0184] In the embodiments disclosed above, the crystallites can at least partially comprise nucleation sites at the grain boundaries and / or contain enrichments comprising lanthanum, in particular lanthanum compounds, at least partially at the grain boundaries of the crystallites.

[0185] In the operating state, the crystal aggregates of the crystallizable or partially crystallized glasses disclosed herein counteract the displacement of volume elements of the at least partially crystallized glass against each other.

[0186] In the joints disclosed here, the surface of the at least partially crystallized glass is meniscus-free.

[0187] In the joining connection disclosed herein, the joining partner can comprise a metal, in particular a metal from the group of steels, for example, standard steels, stainless steels, and high-temperature-resistant ferritic steels, which are also known under the brand name Thermax, for example, Thermax 4016, Thermax 4742, or Thermax 4762 or Crofer 22 APU or Crofer 22 H, or NiFe-based materials, for example, NiFe 45, NiFe 47, or nickel-plated pins, or known under the brand name Inconel, for example, Inconel 718 or X-750, or steels, for example, known under the designations CF25, Alloy 600, Alloy 601, Alloy 625, Alloy 690, SUS 310S, SUS 430, SUH 446, or SUS 316, or austenitic steels such as 1.4762. 1.4828 or 1.4841, Kanthal heating wire or a high-temperature stable ceramic compound, for example Forsterite, an aluminum oxide-based ceramic or a zirconium oxide-based ceramic, for example a ceramic comprising Y-stabilized zirconium oxide.

[0188] The joining connections disclosed herein have a helium leakage rate of less than 10⁻⁸ < mbar * I / s and / or comprise an at least partially crystallized glass having a Young's modulus between 80 GPa and 200 GPa, preferably a Young's modulus between 100 GPa and 125 GPa.

[0189] In the crystallizable or at least partially crystallizable glass disclosed herein, the CaO content of the crystallizable or at least partially crystallizable glass can be between at least 35 mol% and at most 46 mol%, preferably between at least 35 mol% and less than 43.5 mol%, and / or the MgO content of the crystallizable or at least partially crystallizable glass can be between 5 mol% and less than 13 mol%.

[0190] In the crystallizable or at least partially crystallized glass disclosed herein, the glass can be in the form of at least partially crystallized glass and have a linear coefficient of thermal expansion in the temperature range from 20°C to 700°C of more than 9 * 10 -6< / K, preferably of more than 10 * 10 -6< / K, and wherein, particularly preferably, the linear coefficient of thermal expansion of the at least partially crystallized glass in the temperature range from 20°C to 1000°C is more than 9 * 10 -6< / K, preferably more than 9.5 * 10 -6< / K.

[0191] In the case of the crystallizable or at least partially crystallizable glass disclosed herein, the glass, as a crystallizable glass, can have a transformation temperature Tg of more than 720°C.

[0192] In the case of the crystallizable or at least partially crystallizable glass disclosed herein, the temperature of the crystallizable glass for the specific electrical resistance of 10 8< Ω * cm, preferably determined according to DIN 52326, tk 100, is 500°C or more.

[0193] In the crystallizable or at least partially crystallized glass disclosed herein, the at least partially crystallized glass may comprise crystallites of calcium magnesium silicates, preferably of CaO-rich calcium magnesium silicates, in particular of CaO-rich calcium magnesium nesosilicates and / or group silicates, such as merwinite and / or a mixed crystal with a merwinite structure, and alternatively or additionally a crystal phase with a melilite structure, such as ekermanite Ca 2 MgSi 2 O 7 and / or gehlenite Ca 2 Al[AlSiO 7 ] and / or mixed crystals thereof, and / or a crystal phase with an augite structure. Reference symbol list

[0194] 1 Crystal aggregate 2 Crystallite 21 Crystallites at grain boundaries 22 Needle-like crystallites 23 Rod- or plate-shaped crystallites 3 Residual glass 4 Pore 5 Joining joint 51 First joining partner 511 Top edge of the first joining partner 52 Second joining partner 521 Top edge of the second joining partner 53 Insulating component 54 Part of the insulating component arranged between the joining partners 55 Joining partner 51 Protruding section of the insulating component, creepage distance extension 56 Reinforcement 57 Essentially annular component 58 Essentially annular component 59 Essentially annular component M Centerline S Structure forming the creepage distance extension O Top surface of the insulating component 53 Rv Radius of rounding at the edge St Line written with a pen on the surface of the structure S or the surface O Radial direction

Claims

1. A crystallisable or at least partially crystallised glass, comprising La2O3more than 0.3 mol% to less than 5 mol%, preferably less than or equal to 4.5 mol%, most preferably less than or equal to 4 mol%;Nb2O50 mol% to 9 mol%;Ta2O50 mol% to 7 mol%; with Σ (A2O5)more than 0.2 mol% to 9 mol%, where A is an element which usually has the oxidation number V+ in oxides, and which in particular comprises Nb, Ta, or P and / or mixtures thereof; wherein the crystallisable or at least partially crystallised glass comprises an oxide RO, with Σ (RO)≤ 55 mol%, where R is an element which, in oxides, usually has the oxidation number II+; and comprising SiO230 mol% to 40 mol%;Al2O33 mol% to 12 mol%;CaO32 mol% to 46 mol%;MgO5 mol% to 15 mol%;ZnO0 mol% to 10 mol%.

2. The crystallisable or at least partially crystallised glass according to claim 1, wherein R comprises Ca, Mg, or Zn, and / or mixtures thereof.

3. The crystallisable or at least partially crystallised glass according to any one of claims 1 or 2, comprising ZrO20 mol% to 4 mol%, preferably at most 3 mol%; and / orTiO20 mol% to 4 mol%, preferably at most 3 mol%; and / orMnO20 mol% to 5 mol%.

4. The crystallisable or at least partially crystallised glass according to any one of claims 1 to 3, wherein - the CaO content of the crystallisable or at least partially crystallised glass is between at least 35 mol% and at most 46 mol%, preferably between at least 35 mol% and less than 43.5 mol%; and / or - the MgO content of the crystallisable or at least partially crystallised glass is between 5 mol% and less than 13 mol%; and / or - the glass is provided in the form of a crystallisable glass and has a transition temperature Tg of more than 720 °C; and / or - the crystallisable glass has a coefficient of linear thermal expansion of more than 8 * 10-6 / K in a temperature range from 20 °C to 300 °C, and preferably of more than 9 * 10-6 / K in a temperature range from 20 °C to 700 °C; and / or - the glass is provided in the form of an at least partially crystallised glass and has a coefficient of linear thermal expansion of more than 9 * 10-6 / K, preferably more than 10 * 10-6 / K in the temperature range from 20 °C to 700 °C, and wherein, most preferably, the coefficient of linear thermal expansion of the at least partially crystallised glass is greater than 9 * 10-6 / K, preferably greater than 9.5 * 10-6 / K in the temperature range from 20 °C to 1000 °C.

5. The crystallisable or at least partially crystallised glass according to any one of claims 1 to 4, wherein the crystallisable glass exhibits a temperature, tK100, for electrical resistivity of 108 Ω·cm, preferably determined according to DIN 52326, of 500 °C or more; and / or wherein the at least partially crystallised glass includes crystallites of calcium-magnesium silicates, preferably of CaO-rich calcium-magnesium silicates, in particular of CaO-rich calcium-magnesium island silicates and / or group silicates, such as merwinite and / or a solid solution with a merwinite structure, and alternatively or additionally a crystal phase with a melilite structure, such as åkermanite Ca2MgSi2O7 and / or gehlenite Ca2Al[AlSiO7] and / or solid solutions thereof, and / or a crystal phase with an augite structure.

6. A product, in particular a retaining component and / or insulating component and / or additive structure, comprising an at least partially crystallised glass according to claim 1; preferably producible from a sintered body comprising an at least partially crystallisable glass according to claim 1, wherein the sintered body preferably comprises the crystallisable glass in the form of a glass powder, wherein, particularly preferably, the glass powder comprising powder grains having grain surfaces.

7. The product according to claim 6 in the form of a joint connection, in particular a heat resistant and / or mechanically highly resilient joint connection, comprising the at least partially crystallised glass and a joining partner.

8. The joint connection according to claim 7, wherein the crystallites at least partially comprise crystallisation nuclei at the grain boundaries; and / or wherein the grain boundaries of the crystallites, at least in part, have enrichments in lanthanum arranged thereon, in particular comprising lanthanum compounds.

9. The joint connection according to any one of claims 7 or 8, exhibiting at least one of the following features: - the difference, as an absolute value, between thermal expansion coefficients of the joining partner and the at least partially crystallised glass is 5 * 10-6 / K or less, preferably 3 * 10-6 / K or less, and most preferably 1 * 10-6 / K or less; - the joint connection withstands operating temperatures of at least 1000 °C, and the joint connection in particular is shock-resistant and vibration-resistant, measured according to ISO 16750-3; - during operation, the crystal aggregates counteract a displacement of volume elements of the at least partially crystallised glass relative to one another; - the surface of the at least partially crystallised glass exhibits no meniscus; - an at least predominantly amorphous glass layer is provided in the transition zone between the surface of the joining partner and the surface of the at least partially crystallised glass, which glass layer preferably includes less than 10 pores per cm3 and / or preferably has a thickness of 5 µm or less, more preferably of 2 µm or less, and most preferably of 1 µm or less; - the joining partner comprises a metal, in particular a metal from the group of steels, such as normal steels, high-grade steels, stainless steels, and heat resistant ferritic steels, also known under the brand name Thermax, e.g. Thermax 4016, Thermax 4742, or Thermax 4762, or Crofer 22 APU, or CroFer 22 H, or NiFe-based materials, e.g. NiFe45, NiFe47, or nickel-plated pins, or known under the brand name Inconel, e.g. Inconel 718 or X-750, or steels such as known under the designations CF25, Alloy 600, Alloy 625, Alloy 690, SUS310S, SUS430, SUH446, or SUS316, or austenitic steels such as 1.4828 or 1.4841, or a heat-resistant ceramic compound such as an aluminium oxide-based ceramic or a zirconium oxide-based ceramic, for example a ceramic comprising Y-stabilized zirconium oxide; - the joint connection exhibits a helium leak rate of less than 10-8 mbar * l / s; and / or - comprises an at least partially crystallised glass which has a Young's modulus between 80 GPa and 200 GPa, preferably a Young's modulus between 100 GPa and 125 GPa.

10. The joint connection according to any one of claims 7 or 9, comprising an electrically insulating component (53) and at least two joining partners (51, 52), wherein at least one of the joining partners (51, 52) is kept electrically insulated from at least one further of the joining partners (51, 52) by the electrically insulating component (53); and wherein the surface of the electrically insulating component (53) extending between the joining partners defines a structure (S), in particular an elevation or depression which elongates in particular a direct path along the surface from the at least one joining partner to the at least one further joining partner compared to a surface without said structure (S); and wherein said structure (S) preferably completely surrounds at least one joining partner; wherein the insulating component (53) or the structure (S) comprises or is made of the crystallisable or at least partially crystallised glass.

11. The joint connection according to claim 10, exhibiting at least one of the following features: - the structure (S) is made integral with and of the same material as the portion (54) of the insulating component (53) that extends between the joining partners (51, 52) and is bonded to each of the joining partners and preferably glass-fused thereto, wherein, preferably, the material of the insulating component (53) comprises an at least partially crystallised glass; - an at least predominantly amorphous glass layer is provided in the transition zone between the surface of the joining partner and the surface of the at least partially crystallised glass, which glass layer preferably comprises less than 10 pores per cm3 and / or which preferably has a thickness of 5 µm or less, more preferably 2 µm or less, and most preferably 1 µm or less; - the structure (S) comprises crystallisable or at least partially crystallised glass, and an at least predominantly amorphous boundary layer is provided on the surface of the structure (S), in particular in the form of a glass layer which is substantially free of open pores and in particular includes less than 10 pores per cm3, and which has a thickness of 5 µm or less, preferably 2 µm or less, and most preferably 1 µm or less.

12. The joint connection according to claim 10, wherein the structure (S) is not made of the same material as said portion (54) of the insulating component (53) that extends between the joining partners (51, 52) and is bonded to each of the joining partners and preferably glass-fused thereto, preferably exhibiting at least one of the following features: - the structure (S) is not made of the same material as the portion (54) of the insulating component (53) that extends between the joining partners (51, 52) and is bonded to each of the joining partners and preferably glass-fused thereto, and comprises a heat-resistant ceramic material such as forsterite, an aluminium oxide-based ceramic, or a zirconium oxide-based ceramic, for example a ceramic comprising Y-stabilized zirconium oxide; - the structure (S) is not made of the same material as the portion (54) of the insulating component (53) that extends between the joining partners (51, 52) and is bonded to each of the joining partners and preferably glass-fused thereto, and the structure (S) is disposed on the portion (54) of the insulating component (53) so as to be approximately radially centered thereto and preferably protruding into it, at least partially.

13. The joint connection according to any one of claims 10 to 12, exhibiting at least one of the following features: - the structure (S) comprises a reinforcement (56), and the reinforcement (56) comprises a metal foil, or a sheet metal, or a metallic laid scrim, mesh, or knitted fabric, said metal preferably consisting of a ferritic steel or comprising steel; - the structure (S) has edges having a rounding radius Rv of less than one tenth of a millimetre, preferably less than one twentieth of a millimetre, and of more than 10 µm.

14. The joint connection according to any one of claims 7 to 13, comprising at least partially crystallised glass and a joining partner; wherein the at least partially crystallised glass includes a residual glass fraction of less than 10 %, preferably less than 5 %, based on the volume; wherein the at least partially crystallised glass includes crystal aggregates; wherein said crystal aggregates are formed by a large number of crystallites; wherein the crystallites are preferably needle-shaped and / or platelet-shaped; wherein the crystallites are particularly preferably arranged in a radiating pattern such as a spherulitic and / or fan-shaped pattern and / or are rod-shaped and / or platelet-shaped and distributed throughout the at least partially crystallised glass, and comprising in particular one or the insulating component (53).

15. Use of a joint connection according to any one of claims 7 to 14 or of a product according to claim 6 in a sensor such as an exhaust gas sensor, a pressure sensor, a particle sensor, e.g. a soot particle sensor, and / or a temperature sensor, and / or in an NOx sensor, and / or in an oxygen sensor, and / or in a feedthrough of a compressor and / or an e-compressor, and / or as an electrical power feedthrough of an exhaust gas component, and / or in a fuel cell, and / or in a feedthrough of a chemical reactor.