Oxygen sensor core and preparation method therefor, oxygen sensor, engine and vehicle

Abstract

Provided in the present application are an oxygen sensor core and a preparation method therefor, an oxygen sensor, an engine, and a vehicle. The oxygen sensor core comprises a first zirconium oxide layer, a first interface layer, a first aluminum oxide layer, a heating electrode layer, a second aluminum oxide layer, a second interface layer and a second zirconium oxide layer, which are sequentially arranged in a stacked manner, wherein the first interface layer and the second interface layer comprise aluminum oxide and zirconium oxide.

Description

Oxygen sensor core, preparation method thereof, oxygen sensor, engine and vehicle

[0001] The present application claims priority to the Chinese patent application No. 202410844548.8, filed on June 26, 2024, to the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of sensors, in particular to an oxygen sensor core, a preparation method thereof, an oxygen sensor, an engine and a vehicle. BACKGROUND

[0003] The commonly used zirconia oxygen sensor core usually covers an insulating layer on the surface of the two sides of the heating electrode layer, and the commonly used material of the insulating layer is pure alumina ceramic material. However, since the thermal expansion coefficients of alumina and zirconia are different, and the final sintering temperatures are quite different, it is difficult to simultaneously satisfy the sintering densification when co-sintering alumina and zirconia, and the interface bonding effect of the two materials is not good. When subjected to cold and hot impact, the alumina layer and the zirconia layer are prone to peeling, falling off and delamination, which cannot meet the needs of the oxygen sensor in the actual use process. TECHNICAL SOLUTION

[0004] In view of this, the present application provides an oxygen sensor core, a preparation method thereof and an application. The oxygen sensor core comprises a first zirconia layer, a first interface layer, a first alumina layer, a heating electrode layer, a second alumina layer, a second interface layer and a second zirconia layer which are sequentially stacked. The first interface layer and the second interface layer comprise alumina and zirconia. By specially designing the components of the zirconia layer and the alumina layer, an interface layer with special phase composition is formed between the zirconia layer and the alumina layer. On the one hand, the sintering temperature of each layer of the oxygen sensor core is adjusted, so that the zirconia and the alumina can be co-sintered to form a dense layer. On the other hand, the bonding force between the zirconia layer and the alumina layer is significantly improved, and the impact resistance and service life of the oxygen sensor core are improved.

[0005] The first aspect of the present application provides an oxygen sensor core, which comprises a first zirconia layer, a first interface layer, a first alumina layer, a heating electrode layer, a second alumina layer, a second interface layer and a second zirconia layer which are sequentially stacked. The first interface layer and the second interface layer comprise alumina and zirconia.

[0006] In the embodiments of the present application, the zirconia is tetragonal zirconia and / or cubic zirconia.

[0007] In some embodiments of the present application, the first interface layer and the second interface layer further comprise one or more of mullite and zirconium silicate, wherein the sum of the mass percentage of the mullite and the zirconium silicate is 1-3%.

[0008] In some embodiments of the present application, the thickness of the first interface layer and the second interface layer is independently 2-10 μm.

[0009] In some embodiments of the present application, the first interface layer and the second interface layer further comprise lanthanum aluminate, wherein the mass percentage of the lanthanum aluminate is 3-5%.

[0010] In some embodiments of the present application, the first interface layer and the second interface layer further comprise one or more of mullite and zirconium silicate, wherein the sum of the mass percentage of the mullite and the zirconium silicate is 1-3%.

[0011] In some embodiments of the present application, the first interface layer and the second interface layer further comprise barium zirconium silicate, wherein the mass percentage of the barium zirconium silicate is 3-5%.

[0012] In some embodiments of the present application, the first interface layer and the second interface layer further comprise one or more of barium aluminate, zirconium silicate, barium zirconate and barium silicate, wherein the sum of the mass percentage of the barium aluminate, the zirconium silicate, the barium zirconate and the barium silicate is 1-3%.

[0013] In some embodiments of the present application, the thickness of the first alumina layer and the second alumina layer is independently 15-25 μm, the thickness of the first zirconia layer and the second zirconia layer is independently 0.35-0.65 mm, and the thickness of the heating electrode layer is 12-20 μm.

[0014] In some embodiments of the present application, the first alumina layer and the second alumina layer comprise alumina, wherein the mass percentage of the alumina is 95-99%.

[0015] In some embodiments of the present application, the first alumina layer and the second alumina layer further comprise one or more of mullite, lanthanum aluminate, barium aluminate and barium silicate.

[0016] In some embodiments of the present application, the first zirconia layer and the second zirconia layer comprise zirconia, wherein the mass percentage of the zirconia is 85-92%.

[0017] In some embodiments of the present application, the first zirconia layer and the second zirconia layer further comprise one or more of quartz, mullite and zirconium silicate.

[0018] In the embodiments of the present application, the first zirconium oxide layer, the first aluminum oxide layer, the second aluminum oxide layer and the second zirconium oxide layer are independently prepared by any one of a casting process, a screen printing process, surface coating and dry pressing.

[0019] The second aspect of the present application provides a preparation method of the oxygen sensor core provided by the first aspect of the present application, comprising:

[0020] An aluminum oxide layer and a zirconium oxide layer are sequentially arranged on the surface of the heating electrode.

[0021] The oxygen sensor core is obtained after sintering treatment.

[0022] In the embodiments of the present application, the method of arranging the aluminum oxide layer and the zirconium oxide layer comprises at least one of a casting process, a screen printing process, surface coating and dry pressing.

[0023] In the embodiments of the present application, the raw material of the aluminum oxide layer comprises aluminum oxide, silicon oxide and a first sintering aid, wherein the mass percentage of the aluminum oxide is 90%-97%.

[0024] In the embodiments of the present application, the first sintering aid comprises one or more of magnesium oxide, yttrium oxide, calcium oxide, lanthanum oxide, barium oxide, barium sulfate and barium carbonate.

[0025] In the embodiments of the present application, the raw material of the zirconium oxide layer comprises zirconium oxide, yttrium oxide and a second sintering aid, wherein the mass percentage of the zirconium oxide is 88%-92%.

[0026] In the embodiments of the present application, the second sintering aid comprises one or more of silicon oxide, lanthanum oxide, aluminum oxide and cerium oxide.

[0027] In the embodiments of the present application, the average particle size of the aluminum oxide is 0.05-3 μm, and the average particle size of the zirconium oxide is 0.05-3 μm.

[0028] In the embodiments of the present application, the sintering treatment is performed at a temperature of 1400-1500℃.

[0029] The third aspect of the present application provides an oxygen sensor, which comprises the oxygen sensor core of the first aspect of the present application or the oxygen sensor core prepared by the preparation method of the second aspect of the present application.

[0030] The fourth aspect of the present application provides an engine, which comprises the oxygen sensor of the third aspect of the present application.

[0031] The fifth aspect of the present application provides a vehicle, which comprises the engine of the fourth aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0033] Fig. 1 is a schematic diagram of the cross-sectional structure of the oxygen sensor core provided by an embodiment of the present application;

[0034] Fig. 2 is the SEM (Scanning Electron Microscope) characterization result at the first interface layer of the oxygen sensor core of Example 1 and the EDS (Energy Dispersive X-ray Spectroscopy) spectrum of lanthanum element and silicon element;

[0035] Fig. 3 is the SEM characterization result at the first interface layer of the oxygen sensor core of Example 5 and the EDS spectrum of barium element and silicon element.

[0036] EXPLANATION OF REFERENCE NUMERALS

[0037] 100 - oxygen sensor core; 101 - first zirconia layer; 102 - first interface layer; 103 - first alumina layer; 104 - heating electrode layer; 105 - second alumina layer; 106 - second interface layer; 107 - second zirconia layer. Embodiments of the present application

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative work are within the scope of protection of the present application.

[0039] The zirconia oxygen sensor is used to measure the oxygen potential in various heating furnaces or exhaust pipes by using a zirconia ceramic sensitive element, and then the corresponding oxygen concentration is calculated through the chemical equilibrium principle, so as to achieve the purpose of monitoring and controlling the combustion atmosphere, and ensure the product quality and the tail gas emission standard.

[0040] The commonly used zirconia oxygen sensor core currently has a structure of two zirconia layers sandwiching a heating electrode layer, and a layer of insulating layer is covered on the surface of the two sides of the heating electrode layer. The commonly used material of the insulating layer is aluminum oxide ceramic material. However, because the thermal expansion coefficients of aluminum oxide and zirconia are different, and the final sintering temperatures are quite different, it is difficult to simultaneously satisfy the sintering densification by co-sintering aluminum oxide and zirconia. In addition, the interface bonding effect of the two materials is not good, and the interface bonding force between the zirconia layer and the aluminum oxide layer is usually provided by physical adhesion or a small amount of partial ionic bond adhesion formed by atomic diffusion. The interface bonding force is weak, and when cold and hot shock is performed, the aluminum oxide layer and the zirconia layer are prone to peeling, falling off, and delamination, which cannot meet the needs of the oxygen sensor in the actual use process.

[0041] In view of the above problems, the present application provides an oxygen sensor core, which comprises a first zirconia layer, a first interface layer, a first aluminum oxide layer, a heating electrode layer, a second aluminum oxide layer, a second interface layer and a second zirconia layer which are sequentially stacked. The present application specially designs the components of the zirconia layer and the aluminum oxide layer, so that an interface layer with special phase composition is formed between the zirconia layer and the aluminum oxide layer. On the one hand, the sintering temperature of each layer of the oxygen sensor core is adjusted, so that the zirconia and the aluminum oxide can be co-sintered to form a dense layer. On the other hand, the interface bonding force between the zirconia layer and the aluminum oxide layer is also significantly improved, and the impact resistance and service life of the oxygen sensor core are improved.

[0042] As shown in FIG. 1, the present application provides an oxygen sensor core 100, which comprises a first zirconia layer 101, a first interface layer 102, a first alumina layer 103, a heating electrode layer 104, a second alumina layer 105, a second interface layer 106 and a second zirconia layer 107 which are sequentially stacked. In the present application, the first interface layer 102 and the second interface layer 106 both comprise alumina and zirconia. The present application specially designs the components of the first zirconia layer 101, the second zirconia layer 107, the first alumina layer 103 and the second alumina layer 105 of the oxygen sensor core, so that an interface bonding layer of zirconia and alumina, i.e. the first interface layer 102, is formed between the first zirconia layer 101 and the first alumina layer 103, and an interface bonding layer of zirconia and alumina, i.e. the second interface layer 106, is formed between the second zirconia layer 107 and the second alumina layer 105. The first interface layer 102 and the second interface layer 106 are interface bonding layers of zirconia and alumina formed by atomic diffusion or chemical bonds, and the interface bonding layer comprises alumina in the alumina layer and zirconia in the zirconia layer. The first interface layer 102 and the second interface layer 106 significantly improve the interface bonding force between the alumina layer and the zirconia layer, effectively prevent the alumina layer and the zirconia layer from peeling, falling off or delaminating during use, and improve the cold-heat shock resistance of the oxygen sensor core. In addition, the components of the alumina layer and the zirconia layer are specially designed, and part of the components can form a small amount of liquid phase as a sintering aid with the alumina. The liquid phase can promote the mass transfer process during sintering, thereby effectively reducing the sintering temperature of the alumina layer. On the premise of not reducing the physical and chemical properties of the alumina layer and the zirconia layer, the alumina layer and the zirconia layer are co-densified sintered. In the present application, the alumina in the first interface layer 102 and the second interface layer 106 is α-alumina, and the zirconia in the first interface layer 102 and the second interface layer 106 is tetragonal zirconia and / or cubic zirconia. In some specific embodiments, the zirconia in the first interface layer 102 and the second interface layer 106 is tetragonal zirconia. The use of tetragonal zirconia can further improve the bonding force between the alumina layer and the zirconia layer and further improve the mechanical properties of the overall oxygen sensor core.

[0043] In some embodiments, the first interface layer 102 has an alumina content of 84-91% by mass and a zirconia content of 5-8% by mass. In some embodiments, the first interface layer 102 has an alumina content of, for example, 84%, 84.5%, 85%, 85.5%, 86%, 86.5%, 87%, 87.5%, 88%, 88.5%, 89%, 89.5%, 90%, 90.5%, or 91% by mass and a zirconia content of, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8% by mass. In some embodiments, the second interface layer 106 has an alumina content of 84-91% by mass and a zirconia content of 5-8% by mass. In some embodiments, the second interface layer 106 has an alumina content of, for example, 84%, 84.5%, 85%, 85.5%, 86%, 86.5%, 87%, 87.5%, 88%, 88.5%, 89%, 89.5%, 90%, 90.5%, or 91% by mass and a zirconia content of, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8% by mass. In some embodiments, the first interface layer 102 and the second interface layer 106 have the same alumina content and the same zirconia content. In some embodiments, the first interface layer 102 and the second interface layer 106 have different alumina contents and / or different zirconia contents. Because alumina and zirconia are difficult to diffuse into each other during solid-phase sintering, the alumina layer and the zirconia layer are designed to have specific compositions and contents so that they can form a solid solution at the interface to obtain an interface layer containing zirconia, alumina, and a solid solution of the two. The other components in the alumina layer and the zirconia layer form specific phases at the interface layer, thereby improving the bonding strength between the zirconia layer and the alumina layer in the oxygen sensor core.

[0044] In some embodiments of the present application, the first interface layer 102 and the second interface layer 106 further comprise lanthanum aluminate (La2Al2O6), the mass percentage of lanthanum aluminate in the first interface layer 102 is 3%-5%, and / or the mass percentage of lanthanum aluminate in the second interface layer 106 is 3%-5%. In some specific embodiments, the mass percentage of lanthanum aluminate in the first interface layer 102 can be, for example, 3%, 3.5%, 4%, 4.5%, or 5%; and / or the mass percentage of lanthanum aluminate in the second interface layer 106 can be, for example, 3%, 3.5%, 4%, 4.5%, or 5%. In some embodiments, when the first interface layer 102 comprises lanthanum aluminate, the first interface layer 102 further comprises one or more of mullite and zircon silicate, and the sum of the mass percentages of mullite and zircon silicate in the first interface layer is 1%-3%. In some embodiments, when the second interface layer 106 comprises lanthanum aluminate, the second interface layer 106 further comprises one or more of mullite (3Al2O3·2SiO2) and zircon silicate (ZrSiO4), and the sum of the mass percentages of mullite and zircon silicate in the second interface layer is 1%-3%. In some embodiments, lanthanum oxide is included in the raw material for preparing the zirconia layer and / or the alumina layer, and the lanthanum oxide can both react with the alumina to form lanthanum aluminate at the interface layer and form a solid solution with the zirconia, thereby further enhancing the interfacial bonding between the alumina layer and the zirconia layer. Therefore, the appropriate content of lanthanum aluminate phase in the interface layer can further increase the interfacial bonding strength between the zirconia layer and the alumina layer.

[0045] In some other embodiments of the present application, the first interface layer 102 and the second interface layer 106 further comprise barium zirconium silicate (Ba2Zr2Si3O 12) and / or the mass percentage of barium zirconium silicate in the second interface layer 106 is 3%-5%. In some embodiments, the mass percentage of barium zirconium silicate in the first interface layer 102 can be, for example, 3%, 3.5%, 4%, 4.5%, 5%; and / or the mass percentage of barium zirconium silicate in the second interface layer 106 can be, for example, 3%, 3.5%, 4%, 4.5%, 5%. In some embodiments, when barium zirconium silicate is included in the first interface layer 102, the first interface layer 102 further includes one or more of barium aluminate (BaAl204), zirconium silicate (Zr2Si04), barium zirconate (BaZr03), and barium silicate (BaSi04); the sum of the mass percentages of barium aluminate, zirconium silicate, barium zirconate, and barium silicate in the first interface layer is 1%-3%. In some embodiments, when barium zirconium silicate is included in the second interface layer 106, the second interface layer 106 further includes one or more of barium aluminate (BaAl204), zirconium silicate (Zr2Si04), barium zirconate (BaZr03), and barium silicate (BaSi04); the sum of the mass percentages of barium aluminate, zirconium silicate, barium zirconate, and barium silicate in the first interface layer is 1%-3%. In some embodiments, barium oxide and silicon oxide are included in the raw material for preparing the zirconia layer and / or the alumina layer, and after the sintering process, the barium oxide and silicon oxide can form a barium zirconium silicate phase with the zirconia and a liquid phase with the alumina to promote sintering of the alumina, thereby effectively reducing the sintering temperature of the alumina layer. Therefore, a suitable amount of barium zirconium silicate phase in the interface layer can further increase the interfacial bonding strength between the zirconia layer and the alumina layer and effectively reduce the sintering temperature of the alumina layer.

[0046] In some embodiments, the first interface layer 102 and the second interface layer 106 each independently has a thickness of 2-10 μm. In some embodiments, the first interface layer 102 and the second interface layer 106 are layers containing both alumina and zirconia formed by atomic diffusion or chemical bonding of a second phase. The thickness of the first interface layer 102 and the second interface layer 106 can be measured by EDS (Energy Dispersive X-ray Spectroscopy) in a SEM (Scanning Electron Microscope) at a location where barium or lanthanum is enriched. In some embodiments, the thickness of the first interface layer 102 is, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. In some embodiments, the thickness of the second interface layer 106 is, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. By controlling the thickness of the interface layer between the zirconia layer and the alumina layer within a suitable range, the interface bonding between the zirconia layer and the alumina layer can be further improved, and the impact resistance of the oxygen sensor can be further improved.

[0047] In some embodiments, the first alumina layer 103 and the second alumina layer 105 each independently contains alumina. In some embodiments, the first alumina layer 103 and the second alumina layer 105 each independently contains 95-99 wt% of alumina. In some embodiments, the first alumina layer 103 and the second alumina layer 105 each independently contains, for example, 95 wt%, 95.5 wt%, 96 wt%, 96.5 wt%, 97 wt%, 97.5 wt%, 98 wt%, 98.5 wt%, or 99 wt% of alumina. In some embodiments, the alumina is α-alumina. Compared with β-alumina and γ-alumina, the crystal phase of α-alumina is more stable. In some embodiments, the first alumina layer 103 and the second alumina layer 105 each independently further contains one or more of mullite, lanthanum aluminate, barium aluminate, and barium silicate.

[0048] In the embodiments of the present application, the thickness of the first alumina layer 103 and the second alumina layer 105 is independently 15-25 μm. In some specific embodiments, the thickness of the first alumina layer 103 and the second alumina layer 105 can be, for example, independently 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm. In the embodiments of the present application, the thickness of the first alumina layer and the second alumina layer can be the same or different. By controlling the thickness of the alumina layer within a suitable range, the present application can further improve the bonding force between the alumina layer and the zirconia layer while ensuring that the alumina layer provides sufficient insulation capacity, thereby improving the impact resistance and service life of the oxygen sensor core.

[0049] In the embodiments of the present application, the first zirconia layer 101 and the second zirconia layer 107 each comprise zirconia. In the embodiments of the present application, the mass percentage of zirconia in the first zirconia layer 101 and the second zirconia layer 107 is 85-92%, and the mass percentage of zirconia in the first zirconia layer 101 and the second zirconia layer 107 can be the same or different. In some specific embodiments, the mass percentage of zirconia in the first zirconia layer 101 and the second zirconia layer 107 can be, for example, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%. In the embodiments of the present application, the zirconia is tetragonal zirconia and / or cubic zirconia. In some specific embodiments, the zirconia is tetragonal zirconia, which has better mechanical properties than other crystal phases of zirconia. In the embodiments of the present application, the first zirconia layer 101 and the second zirconia layer 107 further comprise one or more of quartz, mullite and zirconium silicate.

[0050] In the embodiments of the present application, the thickness of the first zirconia layer 101 and the second zirconia layer 107 is independently 0.35-0.65 mm. In some specific embodiments, the thickness of the first zirconia layer 101 and the second zirconia layer 107 can be, for example, independently 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm. By controlling the thickness of the zirconia layer within a suitable range, the present application can further improve the bonding force between the alumina layer and the zirconia layer while ensuring sufficient monitoring sensitivity of the oxygen sensor, thereby improving the impact resistance and service life of the oxygen sensor core.

[0051] In the embodiments of the present application, the first zirconia layer 101, the first aluminum oxide layer 103, the second aluminum oxide layer 105 and the second zirconia layer 107 are independently prepared by any one of the following methods: a flow casting process, a screen printing process, a surface coating and dry pressing. In some specific embodiments, the first zirconia layer 101 and the second zirconia layer 107 are prepared by the flow casting process. The first zirconia layer and the second zirconia layer serve as the substrate of the oxygen sensor core, and have a relatively large thickness. The flow casting process can shorten the preparation process, further reduce the production cost, and effectively improve the uniformity of the first zirconia layer and the second zirconia layer. In some specific embodiments, the first aluminum oxide layer 103 and the second aluminum oxide layer 105 are prepared by the screen printing process. Compared with the first zirconia layer and the second zirconia layer, the first aluminum oxide layer and the second aluminum oxide layer have a relatively small thickness. The screen printing process can further improve the uniformity of the first aluminum oxide layer and the second aluminum oxide layer.

[0052] In the embodiments of the present application, the thickness of the heating electrode layer is 12 μm-20 μm. In some specific embodiments, the thickness of the heating electrode layer can be, for example, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0053] The oxygen sensor core provided by the present application is designed by special design of the components of the zirconia layer and the aluminum oxide layer, so that an interface layer including both aluminum oxide and zirconia is formed between the zirconia layer and the aluminum oxide layer. On the one hand, the sintering temperature of each layer of the oxygen sensor core is adjusted, so that the zirconia and the aluminum oxide can be sintered together to form a dense layer. On the other hand, the bonding force between the zirconia layer and the aluminum oxide layer is significantly improved, and the impact resistance and service life of the oxygen sensor core are improved.

[0054] The present application also provides a preparation method of the oxygen sensor core provided above, comprising:

[0055] S101, sequentially arranging an aluminum oxide layer and a zirconia layer on the surface of a heating electrode;

[0056] S102, obtaining an oxygen sensor core after sintering treatment.

[0057] In step S101, the method for arranging the aluminum oxide layer and the zirconia layer includes at least one of the following methods: a flow casting process, a screen printing process, a surface coating and dry pressing. In some embodiments, the method for arranging the zirconia layer can be, for example, a flow casting process. In some embodiments, the method for arranging the aluminum oxide layer can be, for example, a screen printing process.

[0058] In some embodiments, the alumina layer is prepared from a raw material including alumina, silica, and a first sintering aid, wherein the mass of the alumina is 90-97% of the total mass of the raw material. In some embodiments, the mass of the alumina is, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, or 97% of the total mass of the raw material. In some embodiments, the mass of the alumina is 95-97% of the total mass of the raw material. In some embodiments, the mass of the silica is 3-20% of the total mass of the alumina and the first sintering aid. In some embodiments, the mass of the silica is, for example, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 16%, 18%, or 20% of the total mass of the alumina and the first sintering aid. In some embodiments, the content of the alumina, the silica, and the first sintering aid is controlled within a suitable range to further promote sintering of the alumina layer.

[0059] In some embodiments, the first sintering aid includes one or more of magnesium oxide, yttrium oxide, calcium oxide, lanthanum oxide, barium oxide, barium sulfate, and barium carbonate.

[0060] In some embodiments, the average particle size of the alumina is 0.05-3 μm. In some embodiments, the average particle size of the alumina is, for example, 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.5 μm, or 3 μm. In some embodiments, the average particle size of the alumina is 0.15-2 μm.

[0061] In some embodiments, the zirconia layer is prepared from a raw material including zirconia, yttrium oxide, and a second sintering aid, wherein the mass of the zirconia is 88-92% of the total mass of the raw material. In some embodiments, the mass of the zirconia is, for example, 88%, 89%, 90%, 91%, or 92% of the total mass of the raw material. In some embodiments, the mass of the zirconia is 86-91% of the total mass of the raw material. In some embodiments, the second sintering aid includes one or more of silica, lanthanum oxide, alumina, and cerium oxide.

[0062] In the embodiments of the present application, the average particle size of the zirconium oxide is 0.05-3 μm. In some specific embodiments, the average particle size of the zirconium oxide may, for example, be 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.5 μm, 3 μm. In some embodiments, the average particle size of the zirconium oxide may be 0.15-2 μm.

[0063] In the embodiments of the present application, the sintering temperature of the sintering treatment is 1400-1500℃. In some specific embodiments, the sintering temperature of the sintering treatment may, for example, be 1400℃, 1410℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, 1500℃. By specially designing the raw material components for preparing the aluminum oxide layer, the present application significantly reduces the sintering temperature of the aluminum oxide layer and makes it close to that of the zirconium oxide layer, so that the aluminum oxide and the zirconium oxide can be co-sintered in the temperature range of 1400-1500℃, and a dense aluminum oxide layer and a dense zirconium oxide layer are formed.

[0064] The preparation method provided by the present application is simple in process. By specially designing the components of the aluminum oxide layer and the zirconium oxide layer, the present application effectively reduces the sintering temperature of the aluminum oxide layer, so that the aluminum oxide and the zirconium oxide can be co-sintered to form a dense aluminum oxide layer and a dense zirconium oxide layer. In addition, the present application forms an interface layer with a special phase composition between the aluminum oxide layer and the zirconium oxide layer, which significantly improves the bonding force between the aluminum oxide layer and the zirconium oxide layer, and further improves the impact resistance of the oxygen sensor.

[0065] The present application also provides an oxygen sensor, which comprises the oxygen sensor core provided in the foregoing or prepared by the preparation method provided in the foregoing. The sensor adopts the oxygen sensor core provided by the present application, and has high monitoring sensitivity and good cold and hot impact resistance.

[0066] The present application also provides an engine, which comprises the oxygen sensor provided in the foregoing.

[0067] The present application also provides a vehicle, which comprises the engine provided in the foregoing.

[0068] The effects of the technical solutions of the present application are further described below through specific examples.

[0069] Example 1

[0070] The zirconia tape casting ceramic green body is prepared by tape casting process, the prepared zirconia tape casting ceramic green body is used as the first zirconia layer, the thickness of the first zirconia layer is 0.5 mm, the component of the first zirconia layer is 8.8 wt% yttria and 91.2 wt% tetragonal zirconia; screen printing treatment is performed on one side surface of the first zirconia layer, the pressure is 1 kg, the screen printing material composition is 97 wt% alumina, 2.4 wt% lanthanum oxide and 0.6 wt% silicon oxide, the obtained screen printed alumina layer is dried to obtain the first alumina layer, the thickness of the first alumina layer is 25 μm; the heating electrode layer is obtained by screen printing the heating electrode on the surface of the first alumina layer and drying, the thickness of the heating electrode layer is 20 μm; the alumina insulating layer with the same material and thickness as the first alumina layer is screen printed on the surface of the heating electrode layer to obtain the second alumina layer, the thickness of the second alumina layer is 25 μm; the prepared zirconia tape casting ceramic green body is continuously laminated on the second alumina layer as the second zirconia layer, the thickness and component of the second zirconia layer are the same as those of the first zirconia layer; the above heating layer and other layers of the oxygen sensor core body are laminated and isostatic pressed according to the structure and preparation process of the oxygen sensor core body, and the oxygen sensor core body is obtained after sintering treatment; the sintering temperature of the oxygen sensor core body is 1450 ℃, and the highest temperature holding time is 2 h.

[0071] Example 2

[0072] The difference from example 1 is that the screen printing material composition of the first alumina layer and the second alumina layer is 95 wt% alumina, 4 wt% lanthanum oxide and 1 wt% silicon oxide.

[0073] Example 3

[0074] The difference from example 1 is that the screen printing material composition of the first alumina layer and the second alumina layer is 90 wt% alumina, 8 wt% lanthanum oxide and 2 wt% silicon oxide.

[0075] Example 4

[0076] The difference from example 1 is that the screen printing material composition of the first alumina layer and the second alumina layer is 85 wt% alumina, 12 wt% lanthanum oxide and 3 wt% silicon oxide.

[0077] Example 5

[0078] The difference from example 1 is that the screen printing material composition of the first alumina layer and the second alumina layer is 97 wt% alumina, 2.4 wt% barium oxide and 0.6 wt% silicon oxide.

[0079] Example 6

[0080] The difference from Example 1 is that the screen printing material composition of the first and second alumina layers is 95wt% alumina, 4wt% barium oxide, and 1wt% silicon oxide.

[0081] Example 7

[0082] The difference from Example 1 is that the screen printing material composition of the first and second alumina layers is 90wt% alumina, 8wt% barium oxide, and 2wt% silicon oxide.

[0083] Example 8

[0084] The difference from Example 1 is that the material composition of the first zirconia layer is 86.5% cubic phase zirconia and 13.5% yttrium oxide.

[0085] Comparative Example 1

[0086] The difference from Example 1 is that the screen printing material composition of the first and second alumina layers is 100wt% alumina.

[0087] Performance test

[0088] Examples 1-8 and Comparative Example 1 were subjected to performance tests, and the results are shown in Table 1.

[0089] First interface layer thickness: The thickness of the first interface layer and the second interface layer were obtained by measuring the enrichment position of barium or lanthanum elements at the first interface layer of the oxygen sensor core prepared in the examples and comparative examples by EDS in SEM. The measured results are shown in Table 1. As can be seen from the EDS spectrum of the lanthanum and silicon elements at the first interface layer of the oxygen sensor core of Example 1 in FIG. 2, the thickness of the first interface layer of Example 1 is about 5 μm; as can be seen from the EDS spectrum of the barium and silicon elements at the first interface layer of the oxygen sensor core of Example 5 in FIG. 3, the thickness of the first interface layer of Example 5 is about 5 μm.

[0090] Cold and hot impact resistance test:

[0091] The oxygen sensor cores prepared in the examples and comparative examples were connected to a 12V direct current power supply to heat the cores to 720°C and maintain the power for 1 min, and then the power was turned off to cool the cores to room temperature in air atmosphere, which was one cycle; then the above steps were repeated until the cores showed failure behaviors such as cracking, and the number of cold and hot cycles was recorded.

[0092] The oxygen sensor core prepared in the examples and comparative examples was connected to a 14V direct current power supply to heat the core to 800℃ and maintain the power supply for 1 min, and then the power supply was disconnected to cool the core to room temperature in an air atmosphere, which was one cycle; then the above steps were repeated until the core showed failure behaviors such as cracking, and the number of cold and hot cycles was recorded.

[0093] Phase composition: the first interface layer of the oxygen sensor core prepared in the examples and comparative examples was analyzed by XRD (X-ray Diffraction) to obtain the phase composition, and the results are shown in Table 1.

[0094] Table 1

[0095] As can be seen from Table 1, compared with the oxygen sensor core containing an alumina layer with a composition of pure alumina, the examples of the present application specially design the composition and content of the alumina layer, so that an interface layer containing both alumina and zirconia is formed between the zirconia layer and the alumina layer, which significantly improves the bonding force between the zirconia layer and the alumina layer, and further improves the impact resistance and service life of the oxygen sensor core. As can be seen from Comparative Example 1 to Example 4, controlling the composition and content of the raw material for preparing the alumina layer within a suitable range can further improve the bonding force between the zirconia layer and the alumina layer, and further improve the cold and hot impact resistance and service life.

[0096] The above is the preferred embodiment of the present application, but it cannot be interpreted as limiting the scope of the present application. It should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which are also considered to be within the scope of protection of the present application.

Claims

1. An oxygen sensor core, wherein, The oxygen sensor core comprises a first zirconium oxide layer, a first interface layer, a first alumina layer, a heating electrode layer, a second alumina layer, a second interface layer, and a second zirconium oxide layer stacked sequentially. The first interface layer and the second interface layer include alumina and zirconium oxide.

2. The oxygen sensor core as described in claim 1, wherein, The zirconium oxide is tetragonal zirconium oxide and / or cubic zirconium oxide.

3. The oxygen sensor core as described in claim 1 or 2, wherein, In the first interface layer, the alumina content is 84%-91% by mass, and the zirconium oxide content is 5%-8% by mass; and / or In the second interface layer, the alumina has a mass percentage content of 84%-91%, and the zirconium oxide has a mass percentage content of 5%-8%.

4. The oxygen sensor core as described in any one of claims 1-3, wherein, The thicknesses of the first interface layer and the second interface layer are each independently 2 μm-10 μm; and / or The alumina in the first interface layer is α-alumina; and / or The alumina in the second interface layer is α-alumina; and / or The first interface layer is a zirconium oxide and alumina interface bonded entirely by chemical bonds formed by atomic diffusion or a second phase; and / or The second interface layer is a zirconium oxide and alumina interface bonded entirely by chemical bonds formed by atomic diffusion or the second phase.

5. The oxygen sensor core as described in any one of claims 1-4, wherein, The first interface layer further includes lanthanum aluminate, wherein the mass percentage of lanthanum aluminate is 3%-5%; and / or The second interface layer also includes lanthanum aluminate, wherein the mass percentage of lanthanum aluminate is 3%-5%.

6. The oxygen sensor core as described in claim 5, wherein, The first interface layer further includes one or more of mullite and zirconium silicate, wherein the sum of the mass percentages of mullite and zirconium silicate is 1%-3%; and / or The second interface layer also includes one or more of mullite and zirconium silicate, wherein the sum of the mass percentages of mullite and zirconium silicate is 1%-3%.

7. The oxygen sensor core according to any one of claims 1-6, wherein, The first interface layer further includes barium zirconium silicon, wherein the barium zirconium silicon has a mass percentage content of 3%-5%; and / or The second interface layer also includes barium zirconium silicon, wherein the mass percentage of barium zirconium silicon is 3%-5%.

8. The oxygen sensor core as described in claim 7, wherein, The first interface layer further includes one or more of barium aluminate, zirconium silicate, barium zirconate, and barium silicate, wherein the sum of the mass percentages of barium aluminate, zirconium silicate, barium zirconate, and barium silicate is 1%-3%; and / or The second interface layer also includes one or more of barium aluminate, zirconium silicate, barium zirconate, and barium silicate, wherein the sum of the mass percentages of barium aluminate, zirconium silicate, barium zirconate, and barium silicate is 1%-3%.

9. The oxygen sensor core according to any one of claims 1-8, wherein, The thicknesses of the first alumina layer and the second alumina layer are each independently 15 μm-25 μm; and / or The thickness of the first zirconium oxide layer and the second zirconium oxide layer are each independently 0.35 mm to 0.65 mm; and / or The thickness of the heating electrode layer is 12μm-20μm.

10. The oxygen sensor core according to any one of claims 1-9, wherein, The first alumina layer comprises alumina; the first alumina layer further comprises one or more of mullite, lanthanum aluminate, barium aluminate, and barium silicate; wherein the mass percentage of alumina is 95%-99%; and / or; The second alumina layer comprises alumina, wherein the mass percentage of the alumina is 95%-99%; the second alumina layer further comprises one or more of mullite, lanthanum aluminate, barium aluminate, and barium silicate.

11. The oxygen sensor core according to any one of claims 1-10, wherein, The first zirconia layer comprises zirconia; the first zirconia layer further comprises one or more of quartz, mullite, and zirconium silicate; wherein the zirconia has a mass percentage content of 85%-92%; and / or The second zirconia layer comprises zirconia, wherein the zirconia has a mass percentage content of 85%-92%; the second zirconia layer also comprises one or more of quartz, mullite and zirconium silicate.

12. The oxygen sensor core according to any one of claims 1-11, wherein, The first zirconium oxide layer, the first alumina layer, the second alumina layer, and the second zirconium oxide layer are independently prepared by any one of the following methods: casting process, screen printing process, surface coating, and dry pressing.

13. A method for preparing an oxygen sensor core as described in any one of claims 1-12, wherein, include: An alumina layer and a zirconium oxide layer are sequentially deposited on the surface of the heating electrode; and The oxygen sensor core is obtained after sintering.

14. The method for preparing the oxygen sensor core as described in claim 13, wherein, The method for setting the alumina layer and the zirconium oxide layer includes at least one of the following: casting process, screen printing process, surface coating, and dry pressing.

15. The method for preparing the oxygen sensor core as described in claim 13 or 14, wherein, The raw materials for the alumina layer include alumina, silicon oxide, and a first sintering aid, wherein the mass percentage of alumina is 90%-97%; the first sintering aid includes one or more of magnesium oxide, yttrium oxide, calcium oxide, lanthanum oxide, barium oxide, barium sulfate, and barium carbonate.

16. The method for preparing the oxygen sensor core according to any one of claims 13-15, wherein, The raw materials for the zirconium oxide layer include zirconium oxide, yttrium oxide, and a second sintering aid, wherein the zirconium oxide has a mass percentage content of 88%-92%; the second sintering aid includes one or more of silicon oxide, lanthanum oxide, aluminum oxide, and cerium oxide.

17. The method for preparing the oxygen sensor core as described in claim 15 or 16, wherein, The alumina has an average particle size of 0.05 μm-3 μm, and the zirconium oxide has an average particle size of 0.05 μm-3 μm.

18. The method for preparing the oxygen sensor core according to any one of claims 13-17, wherein, The sintering temperature is 1400℃-1500℃.

19. An oxygen sensor, wherein, The oxygen sensor includes the oxygen sensor core as described in any one of claims 1-12 or the oxygen sensor core prepared by the preparation method described in any one of claims 13-18.

20. An engine comprising the oxygen sensor core of claim 19, wherein, The engine includes the oxygen sensor as described in claim 19.

21. A vehicle comprising the engine of claim 20, wherein, The vehicle includes the engine as described in claim 20.

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