Ammonia sensor and manufacturing method thereof

Abstract

The invention relates to an ammonia sensor and a manufacturing method thereof, the ammonia sensor comprises an insulating layer and an electrolyte layer which are laminated, 5-20 wt.% of a compound is added in the insulating layer in contact with the electrolyte layer, and the compound comprises 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface reinforcing oxide. According to the ammonia sensor, 5-20 wt.% of a compound is added into an insulating layer, in contact with an electrolyte layer, of the ammonia sensor, the compound comprises 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface reinforcing oxide, so that the insulating layer close to the electrolyte layer forms a modified functional structure layer, and the interface matching bonding performance of the insulating layer and the electrolyte layer is optimized; the stability of the insulating layer and the electrolyte layer in rapid temperature change is improved, generation and expansion of interface cracks in rapid temperature change are inhibited, the problem of poor thermal shock resistance of the ammonia sensor in special weak links is effectively solved, and the stability and high thermal shock resistance of the ammonia sensor under working conditions are met.

Description

TECHNICAL FIELD

[0001] The present application relates to an ammonia sensor, in particular to an ammonia sensor and a manufacturing method thereof. BACKGROUND

[0002] At present, the pollutants emitted by automobiles mainly include CO, HC, NOx and PM, wherein the exhaust emission of diesel vehicles mainly includes NOx and PM. The selective catalytic reduction (SCR) system is used in the exhaust treatment system of diesel vehicles, and under the action of a catalyst, urea is sprayed to release ammonia gas after pyrolysis to treat nitrogen oxides, so as to reduce NOx in the exhaust to N2. In order to prevent the escape of ammonia gas after urea is converted into ammonia gas and cause secondary pollution, an ammonia sensor for detecting ammonia gas is arranged at the exhaust outlet of the SCR system.

[0003] The ammonia sensor is a device suitable for high temperature, which is a multi-layer composite structure. The ammonia sensor chip is a ceramic chip with certain strength and signal transmission ability, which is obtained by giving the green tape formed by flow casting a special functional electrode structure through a screen printing process, and then through processes such as lamination, warm water pressing, cutting and sintering. Since the ammonia sensor is located on a diesel vehicle, the thermal shock resistance at high temperature is a crucial factor affecting the performance of the ammonia sensor in the harsh working condition of drastic temperature change. That is, when the temperature changes sharply, the ceramic with poor thermal shock resistance will produce cracks between the ceramic layers, causing the product to fail. In addition, the thermal shock resistance of the ammonia sensor product is positively correlated with its insulation performance.

[0004] The existing preparation method of the ammonia sensor ceramic chip mainly includes the following steps: YSZ (yttria-stabilized zirconia) and alumina are respectively flow casted to form YSZ and alumina film strips, then functional electrodes with special patterns are printed on the corresponding film strips, and then the ammonia sensor chip with heating and conduction functions is formed through lamination, warm water pressing, cutting and sintering. According to the existing technology, the ammonia sensor is formed by overlapping the electrolyte layer (such as YSZ, ScSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria) and the like) and the insulating layer (such as alumina). The interlayer bonding of the two is often a weak link. This weak link will often crack during the process of drastic temperature change of the product, thereby reducing the insulation performance of the product. This failure caused by poor thermal shock resistance is fatal to the ammonia sensor. In view of the weak link, a transition layer is often introduced to solve the problem, but the introduction of the transition layer has the problems of complex process and increased cost. Therefore, the present application proposes a method which can not only optimize the problem but also simplify the process and reduce the cost.

[0005] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information which does not constitute the prior art known to those of ordinary skill in the art. SUMMARY

[0006] The main object of the present application is to overcome the drawbacks present in the background art, to provide an ammonia sensor and a manufacturing method thereof.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] An ammonia sensor comprises an insulating layer and an electrolyte layer which are stacked, 5-20 wt.% of a composite is added to the insulating layer in contact with the electrolyte layer, the composite comprises 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface-enhancing oxide.

[0009] Further, the electrolyte material comprises one or more of zirconium oxide, yttrium oxide, scandium oxide, sodium oxide and praseodymium oxide.

[0010] Further, the interface-enhancing oxide comprises one or more of magnesium oxide, lanthanum oxide, silicon oxide, boron oxide and calcium oxide.

[0011] Further, the particle size of the composite is 0.1-1 μm.

[0012] Further, the material of the electrolyte layer is YSZ, ScSZ or GDC.

[0013] Further, the insulating layer comprises aluminum oxide.

[0014] Further, the composite is added only to the insulating layer in contact with the electrolyte layer.

[0015] A manufacturing method of the ammonia sensor comprises the following steps:

[0016] (1) preparing an insulating layer green tape, wherein 5-20 wt.% of a composite is added to the insulating layer green tape to be in contact with the electrolyte layer, the composite comprises 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface-enhancing oxide;

[0017] (2) preparing an electrolyte layer green tape;

[0018] (3) stacking the insulating layer green tape and the electrolyte layer green tape in a preset order to obtain a green body after processing;

[0019] (4) sintering the green body to form an ammonia sensor chip core with a multilayer structure.

[0020] Further, the sintering temperature of step (4) is 1350-1450 °C.

[0021] The present application has the following beneficial effects:

[0022] The application provides an ammonia sensor and a manufacturing method thereof. By adding 5-20 wt.% of a composite in an insulation layer of the ammonia sensor, which is in contact with an electrolyte layer, the composite comprising 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface-enhancing oxide, the insulation layer close to the electrolyte layer is formed into a specially modified functional structure layer, so that the interface matching and bonding performance of the insulation layer and the electrolyte layer is optimized, the stability of the insulation layer and the electrolyte layer in sharp temperature change is improved, the generation and expansion of interface cracks in sharp temperature change are inhibited, the problem of poor thermal shock resistance of the ammonia sensor caused by special weak links is effectively solved, and the stability and high thermal shock resistance of the ammonia sensor under working conditions are met. Meanwhile, the application only needs to add the composite in the insulation layer in contact with the electrolyte layer to realize the special treatment of the corresponding layer in the original structure, and the part not in contact with the electrolyte layer remains the original structure, without additional transition layer, so that the overall strength of the product is ensured, the thermal shock resistance of the product is improved, the process is simplified, and the cost is saved.

[0023] Other advantages of the embodiments of the application will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a decomposition structure schematic diagram of the ammonia sensor of the embodiments of the application.

[0025] Figure 2a It is a cross-sectional schematic diagram of the component and structure distribution of each functional layer of the ammonia sensor of the comparative example.

[0026] Figure 2b It is a cross-sectional schematic diagram of the component and structure distribution of each functional layer of the ammonia sensor of one embodiment of the application.

[0027] Figure 2c It is a cross-sectional schematic diagram of the component and structure distribution of each functional layer of the ammonia sensor of another embodiment of the application.

[0028] Figure 3 It is a micro-morphology diagram of the modified insulation layer and the electrolyte layer after the ammonia sensor of the embodiments of the application is subjected to high-temperature cycle treatment from room temperature to 650 DEG C. DETAILED DESCRIPTION

[0029] The embodiments of the application are described in detail below. It should be emphasized that the following description is only exemplary, but is not intended to limit the scope and application of the application.

[0030] It is to be understood that when an element such as a layer, film or region is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. It will also be understood that, when a device or element is referred to as being "coupled" to another device or element, electrical or mechanical communication can be present between them, but there will not necessarily be direct electrical or direct mechanical contact.

[0031] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, merely describe the orientation in the drawings on which the application embodiments are depicted and are merely used for convenience during description of the application embodiments and in no way refer to or imply the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore must not be construed as limiting the application.

[0032] In addition, the terms "first", "second", "third", etc. are used herein only to describe different instances, and do not imply a relative importance or a specific order of calling. Therefore, features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0033] The embodiments of the application provide an ammonia sensor, comprising an insulating layer and an electrolyte layer arranged in a stack, 5-20 wt.% of a composite is added to the insulating layer in contact with the electrolyte layer, the composite comprises 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface-enhancing oxide. Figure 1 An ammonia sensor with a multi-layer structure of one specific embodiment is shown, which comprises, from top to bottom, a first functional layer (insulating layer) 4, a second functional layer (insulating layer) 5, a third functional layer (electrolyte layer) 6, a fourth functional layer (insulating layer) 7, a fifth functional layer (insulating layer) 8, a sixth functional layer (electrolyte layer) 9, a seventh functional layer (insulating layer) 10, and an eighth functional layer (insulating layer) 11, but the multi-layer structure is only an example, and the specific structure of the ammonia sensor of the application is not limited thereto.

[0034] The existing ammonia sensor is a multi-layer composite structure, and the interface between the insulating layer (such as aluminum oxide) and the electrolyte layer (such as YSZ, ScSZ, GDC) is a weak link. In harsh working conditions with rapid temperature changes, the thermal shock resistance is poor, and interface cracks are easily generated, leading to product failure. The existing technology introduces a transition layer to solve this problem, which has the defects of complex process and increased cost. The core technical concept of the present application is to add 5-20wt.% of a specific composite to the insulating layer in contact with the electrolyte layer, which contains 10-30wt.% of electrolyte material and 70-90wt.% of interface-enhancing oxide, so that the insulating layer near the electrolyte layer forms a modified functional structure layer. The technical advantages are: optimizing the interface matching and bonding performance of the insulating layer and the electrolyte layer, improving the stability of the two in rapid temperature changes, inhibiting the generation and expansion of interface cracks, effectively solving the problem of poor thermal shock resistance; without additional transition layer, only the insulating layer in contact with the electrolyte layer is specially treated, and the non-contact part remains the original structure, which not only ensures the overall strength and improves the thermal shock resistance, but also simplifies the process and saves the cost, meeting the stability and high thermal shock resistance requirements of ammonia sensor in working conditions.

[0035] In some embodiments, the electrolyte material includes one or more of zirconium oxide, yttrium oxide, scandium oxide, sodium oxide, praseodymium oxide.

[0036] In some embodiments, the interface-enhancing oxide includes one or more of magnesium oxide, lanthanum oxide, silicon oxide, boron oxide, calcium oxide.

[0037] In some embodiments, the particle size of the composite is 0.1-1μm.

[0038] In some embodiments, the addition amount of the composite is 10-15wt.%.

[0039] In some embodiments, the content of electrolyte material in the composite is 10-20wt.% and the content of interface-enhancing oxide is 80-90wt.%.

[0040] In some embodiments, the material of the electrolyte layer is YSZ (yttrium-stabilized zirconia), ScSZ (scandium-stabilized zirconia), or GDC (gadolinium-doped ceria).

[0041] In some embodiments, the insulating layer contains aluminum oxide.

[0042] In some embodiments, the composite is added only in the insulation layer in contact with the electrolyte layer. The entire insulation layer in contact with the electrolyte layer in the ammonia sensor is subjected to a special treatment, while the part not in contact with the electrolyte remains in the original structure, which ensures the overall strength of the product and improves the thermal shock resistance of the product, and simplifies the process and saves costs.

[0043] The embodiments of the present application also provide a manufacturing method of the ammonia sensor, comprising the following steps:

[0044] (1) preparing an insulation layer green tape, wherein 5-20 wt.% of a composite is added in the insulation layer green tape to be in contact with the electrolyte layer, the composite comprising 10-30 wt.% of an electrolyte material and 70-90 wt.% of an interface-enhancing oxide;

[0045] (2) preparing an electrolyte layer green tape;

[0046] (3) stacking the insulation layer green tape and the electrolyte layer green tape in a predetermined order to obtain a green body after treatment;

[0047] (4) sintering the green body to form a multilayer ammonia sensor chip core.

[0048] In some embodiments, the sintering temperature in step (4) is 1350-1450°C.

[0049] The ammonia sensor and the manufacturing method thereof have the following technical advantages:

[0050] Optimizing the interface bonding performance: by adding a composite with a specific proportion in the insulation layer in contact with the electrolyte layer, the composite comprising an electrolyte material and an interface-enhancing oxide, the interface matching and bonding performance of the insulation layer and the electrolyte layer can be effectively optimized, and the two can be combined more closely.

[0051] Improving the thermal shock resistance: the stability of the insulation layer and the electrolyte layer in the environment with sharp temperature changes is significantly improved, which can effectively inhibit the generation and expansion of interface cracks when the temperature changes sharply, and fundamentally solves the problem of poor thermal shock resistance of the ammonia sensor due to the special weak link of the overlapping of the insulation layer and the electrolyte layer.

[0052] Simplifying the process and saving costs: without additional transition layers, only the insulation layer in contact with the electrolyte layer is subjected to a special treatment, while the part not in contact with the electrolyte remains in the original structure, which ensures the overall strength of the product, simplifies the production process, and reduces the production cost.

[0053] Meet the working condition use demand: make ammonia sensor can meet the stability requirements in diesel vehicles and other harsh working conditions and high thermal shock resistance ability demand, to ensure that it can still work normally in the environment of temperature changes, effectively play the function of detecting ammonia, avoid the secondary pollution caused by sensor failure and other problems.

[0054] The specific embodiments and experimental verification of the present application are further described below.

[0055] Figure 1 The embodiment shown is an ammonia sensor with a multi-layer structure, which has the following specific structure: there is an upper electrode 1 in the uppermost layer, and a lower electrode 2 in the lowermost layer, and a through hole 3 is provided near the upper electrode 1; from the upper layer to the lower layer, there are a first functional layer (insulating layer) 4, a second functional layer (insulating layer) 5, a third functional layer (electrolyte layer) 6, a fourth functional layer (insulating layer) 7, a fifth functional layer (insulating layer) 8, a sixth functional layer (electrolyte layer) 9, a seventh functional layer (insulating layer) 10, and an eighth functional layer (insulating layer) 11; there are also a first electrode 12, a second electrode 13, a reference electrode one 14, a reference electrode two 15, and a temperature measuring electrode 16; there is a heating wire 17 inside, a sensitive material 18 on the top, and a gas inlet layer one 19, a gas inlet layer two 20, and a gas inlet layer three 21 of porous material. The ammonia sensor adds 5-20 wt.% of a composite in the insulating layer in contact with the electrolyte layer, and the composite contains 10-30 wt.% of electrolyte material and 70-90 wt.% of interface-enhancing oxide.

[0056] Figure 2a The composition and structure distribution of each functional layer of the ammonia sensor of the comparative example are shown. Figure 2b and Figure 2c The composition and structure distribution of each functional layer of the ammonia sensor of two embodiments of the present application are shown respectively. As Figure 2b shown, the embodiment is specially treated in the insulating layer near the electrolyte layer to form a special functional structure layer, and the whole insulating layer (such as aluminum oxide) at this place is modified by a composite material, that is, 5-20 wt.% of a composite is added in the second, fourth, fifth, and seventh functional layers. In addition, see Figure 2c, the fourth and fifth functional layers can also be combined into one functional layer, and the total thickness thereof is unchanged. The composite contains 10-30 wt.% of an electrolyte system such as zirconium oxide, yttrium oxide, scandium oxide, sodium oxide, praseodymium oxide, etc., and contains 70-90 wt.% of one or more interface-enhancing oxides such as magnesium oxide, lanthanum oxide, silicon oxide, boron oxide, calcium oxide, etc., and the particle size in the composite is 0.1-1 μm. In the manufacturing process, the raw materials are prepared and then formed into a green tape, the layers are stacked in the predetermined order, a green body is prepared, and then sintering is performed at 1350-1450 °C to obtain an ammonia sensor chip with thermal shock resistance. By treating the insulating layer in contact with the electrolyte layer in the above manner, the stability of the insulating layer and the electrolyte layer in the case of a sharp change in temperature is improved, and the effective output of the product performance under working conditions is ensured.

[0057] Details of the comparative examples and examples are as follows.

[0058] Comparative Example

[0059] As shown in Figure 2a , the present comparative example provides an ammonia sensor. In terms of structure, the uppermost layer is an upper electrode 1, and the lowermost layer is a lower electrode 2. A through hole 3 is provided near the upper electrode 1. From the upper layer to the lower layer, there are a first functional layer (insulating layer, material: conventional alumina, no composite added) 4, a second functional layer (insulating layer, material: conventional alumina, no composite added) 5, a third functional layer (electrolyte layer, material: YSZ) 6, a fourth functional layer (insulating layer, material: conventional alumina, no composite added) 7, a fifth functional layer (insulating layer, material: conventional alumina, no composite added) 8, a sixth functional layer (electrolyte layer, material: YSZ) 9, a seventh functional layer (insulating layer, material: conventional alumina, no composite added) 10, and an eighth functional layer (insulating layer, material: conventional alumina, no composite added) 11. A first electrode 12, a second electrode 13, a reference electrode 1 14, a reference electrode 2 15, and a temperature measuring electrode 16 are also provided. A heating wire 17 is provided inside, and a sensitive material 18 is provided on the top. There are a porous material gas inlet layer 1 19, a porous material gas inlet layer 2 20, and a porous material gas inlet layer 3 21. In the manufacturing process, the insulating layer raw material (pure alumina) is mixed with a binder, a plasticizer, and other additives, and is subjected to ball milling, defoaming, and other processes to form an insulating layer green tape. The electrolyte layer raw material is also subjected to a similar tape casting process to form an electrolyte layer green tape. Subsequently, the green tapes are stacked in the predetermined order, and a green body is prepared by warm water pressing and other processes. Sintering is performed at 1350-1450 °C in an air atmosphere at a temperature increase rate of 5 °C / min, and then the furnace is cooled after holding for 2 hours. An ammonia sensor chip is obtained after sintering. The structure of this comparative example is similar to that of a conventional ammonia sensor, and the overlapping part of the insulating layer and the electrolyte layer is not specially treated.

[0060] Example 1

[0061] As shown in Figure 2bAs shown, the embodiment provides an ammonia sensor, in structure, the uppermost layer is the upper electrode 1, the lowermost layer is the lower electrode 2, and a through hole 3 is arranged near the upper electrode 1. From the upper layer to the lower layer, there are sequentially distributed: the first functional layer (insulating layer containing aluminum oxide) 4, the second functional layer (insulating layer containing aluminum oxide and adding 13wt.% compound) 5, the third functional layer (electrolyte layer, material is YSZ) 6, the fourth functional layer (insulating layer containing aluminum oxide and adding 13wt.% compound) 7, the fifth functional layer (insulating layer containing aluminum oxide and adding 13wt.% compound) 8, the sixth functional layer (electrolyte layer, material is YSZ) 9, the seventh functional layer (insulating layer containing aluminum oxide and adding 13wt.% compound) 10, and the eighth functional layer (insulating layer containing aluminum oxide) 11. There are also the first electrode 12, the second electrode 13, the reference electrode one 14, the reference electrode two 15, and the temperature measuring electrode 16; the inside is provided with a heating wire 17, the top is provided with a sensitive material 18, and there are the gas inlet layer one 19, the gas inlet layer two 20, and the gas inlet layer three 21 of porous material. In the manufacturing process, the insulating layer raw material (containing aluminum oxide) is mixed with the compound in proportion, the compound contains 15wt.% electrolyte material (YSZ) and 85wt.% interface enhanced oxide (lanthanum oxide, calcium oxide, silicon oxide), the compound particle size is controlled in 0.1-1μm, and then the binder, plasticizer and other additives are added, and the insulating layer green tape is prepared through ball milling, defoaming and other processes; the electrolyte layer raw material is prepared into the electrolyte layer green tape through the flow casting process; then the green tapes are stacked in the preset order, and the blank body is prepared through warm water pressing and other treatments, and then the blank body is heated to 1350-1450℃ at a heating rate of 5℃ / min in an air atmosphere, and then cooled in the furnace after holding for 2 hours, and then the sintered body with thermal resistance and thermal shock resistance is obtained. The sintered body is provided with the upper electrode 1, the lower electrode 2, the through hole 3, the first functional layer 4, the second functional layer 5, the third functional layer 6, the fourth functional layer 7, the fifth functional layer 8, the sixth functional layer 9, the seventh functional layer 10, the eighth functional layer 11, the first electrode 12, the second electrode 13, the reference electrode one 14, the reference electrode two 15, the temperature measuring electrode 16, the heating wire 17, the sensitive material 18, the gas inlet layer one 19, the gas inlet layer two 20, and the gas inlet layer three 21. Figure 2c Figure 2c The fifth and seventh functional layers are specially treated to form a special functional structure layer.

[0062] Example 2

[0063] As Figure 1As shown, the ammonia sensor of the present embodiment has a similar overall structure to that of Embodiment 1, and has basic structures such as the upper electrode 1, the lower electrode 2, and the through hole 3. From top to bottom, there are: the first functional layer (insulating layer, containing alumina) 4, the second functional layer (insulating layer, containing alumina and adding 13 wt.% of the composite) 5, the third functional layer (electrolyte layer, material YSZ) 6, the fourth and fifth functional layers (combined insulating layer, containing alumina and adding 13 wt.% of the composite, total thickness is the same as the sum of the thicknesses of the fourth and fifth functional layers in Embodiment 1), the sixth functional layer (electrolyte layer, material YSZ) 9, the seventh functional layer (insulating layer, containing alumina and adding 13 wt.% of the composite) 10, and the eighth functional layer (insulating layer, containing alumina) 11. The rest of the components, such as the electrodes, heating wires, sensitive materials, and gas inlet layers, are arranged in the same way as in Embodiment 1. During production, the insulating layer raw material (containing alumina) is mixed with the composite, which contains 15 wt.% of electrolyte material (YSZ) and 85 wt.% of interface-enhancing oxide (lanthanum oxide, calcium oxide, silicon oxide), and the composite has a particle size of 0.1-1 μm. The insulating layer green tape is produced through a process similar to that of Embodiment 1, including adding additives, ball milling, and defoaming. The electrolyte layer green tape is produced, and the subsequent lamination and sintering steps are also the same as in Embodiment 1. In this embodiment, the insulating layer near the electrolyte layer is specially treated, and the fourth and fifth functional layers are combined into one layer, which still ensures that the insulating layer in contact with the electrolyte layer is modified by the composite.

[0064] Experimental results

[0065] For Figure 3 As shown, the ammonia sensor of the present embodiment has a similar overall structure to that of Embodiment 1, and has basic structures such as the upper electrode 1, the lower electrode 2, and the through hole 3. From top to bottom, there are: the first functional layer (insulating layer, containing alumina) 4, the second functional layer (insulating layer, containing alumina and adding 13 wt.% of the composite) 5, the third functional layer (electrolyte layer, material YSZ) 6, the fourth and fifth functional layers (combined insulating layer, containing alumina and adding 13 wt.% of the composite, total thickness is the same as the sum of the thicknesses of the fourth and fifth functional layers in Embodiment 1), the sixth functional layer (electrolyte layer, material YSZ) 9, the seventh functional layer (insulating layer, containing alumina and adding 13 wt.% of the composite) 10, and the eighth functional layer (insulating layer, containing alumina) 11. The rest of the components, such as the electrodes, heating wires, sensitive materials, and gas inlet layers, are arranged in the same way as in Embodiment 1. During production, the insulating layer raw material (containing alumina) is mixed with the composite, which contains 15 wt.% of electrolyte material (YSZ) and 85 wt.% of interface-enhancing oxide (lanthanum oxide, calcium oxide, silicon oxide), and the composite has a particle size of 0.1-1 μm. The insulating layer green tape is produced through a process similar to that of Embodiment 1, including adding additives, ball milling, and defoaming. The electrolyte layer green tape is produced, and the subsequent lamination and sintering steps are also the same as in Embodiment 1. In this embodiment, the insulating layer near the electrolyte layer is specially treated, and the fourth and fifth functional layers are combined into one layer, which still ensures that the insulating layer in contact with the electrolyte layer is modified by the composite.

[0066] The experimental data show that the introduction of the composite into the second, fourth, fifth, and seventh functional layers effectively improves the thermal shock resistance of the ammonia sensor ceramic chip. For example, ​As shown, when the product is treated for 30 cycles, the micro-morphology diagram of the second, fourth, fifth and seventh functional layer with 13wt.% composite introduced in the combination of the third and sixth functional layer shows that there is no micro-crack, the density is high, the anti-breakdown ability is excellent, and the thermal shock resistance at high temperature is improved.

[0067] Table 1 Breakdown strength of the product at different cycle times

[0068]

[0069] The test results show that the introduction of the composite in the second, fourth, fifth and seventh functional layers of the ammonia sensor improves the thermal shock resistance, compared with the structure without adding the composite, the ammonia sensor adopting the structure improves the thermal shock resistance at high temperature, which is beneficial to the matching between the alumina insulation layer and the electrolyte layer. The ammonia sensor adopting the structure improves the anti-breakdown ability of the product, and the anti-breakdown strength of the product with the composite after 50 cycles is 32.67KV·mm, which is increased by 100% compared with the product without the special treatment.

[0070] In summary, by adding 5-20wt.% of the composite in the insulation layer in contact with the electrolyte layer, the composite contains 10-30wt.% of the electrolyte material and 70-90wt.% of the interface reinforcing oxide, the interface bonding performance of the insulation layer and the electrolyte layer is optimized, the generation and expansion of the interface crack when the temperature changes sharply are inhibited, the poor thermal shock resistance problem caused by the special weak link of the ammonia sensor is solved, and the stability and high thermal shock resistance under the working condition are met.

[0071] The above further describes the present application in conjunction with specific / preferred embodiments, and cannot be deemed to limit the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or variations to the described embodiments, and these substitutions or variations shall be deemed to fall within the protection scope of the present application. In the description of the present application, the description of the terms "an embodiment", "some embodiments", "a preferred embodiment", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the case of no mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. An ammonia sensor comprising an insulating layer and an electrolyte layer disposed in a stack, characterized by, 5-20 wt.% of a composite is added in the insulation layer in contact with the electrolyte layer, the composite comprising 10-30 wt.% of electrolyte material and 70-90 wt.% of interface-enhancing oxide.

2. The ammonia sensor according to claim 1, characterized by The electrolyte material comprises one or more of zirconium oxide, yttrium oxide, scandium oxide, sodium oxide, praseodymium oxide.

3. Ammonia sensor according to claim 1 or 2, characterized in that The interface-enhancing oxide comprises one or more of magnesium oxide, lanthanum oxide, silicon oxide, boron oxide, calcium oxide.

4. The ammonia sensor according to any one of claims 1 to 3, characterized by The particle size of the composite is 0.1-1 μm.

5. The ammonia sensor according to any one of claims 1 to 4, characterized by The material of the electrolyte layer is YSZ, ScSZ or GDC.

6. The ammonia sensor according to any one of claims 1 to 5, characterized by The insulation layer comprises aluminum oxide.

7. The ammonia sensor according to any one of claims 1 to 6, characterized by The composite is only added in the insulation layer in contact with the electrolyte layer.

8. A method of manufacturing the ammonia sensor according to any one of claims 1 to 7, characterized by, The method comprises the following steps: (1) preparing an insulation layer green tape, wherein 5-20 wt.% of a composite is added in the insulation layer green tape to be in contact with the electrolyte layer, the composite comprising 10-30 wt.% of electrolyte material and 70-90 wt.% of interface-enhancing oxide; (2) preparing an electrolyte layer green tape; (3) stacking the insulation layer green tape and the electrolyte layer green tape in a preset order to obtain a green body after processing; (4) sintering the green body to form a multi-layer structure ammonia sensor chip.

9. The production method according to claim 8, characterized by, The sintering temperature of step (4) is 1350-1450 °C.

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