A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermosensitive ceramic material and preparation method thereof

Abstract

The present invention discloses a Zr 4+ Doped aY2O3‑bYCr 0.5 Mn 0.5 O3 thermal sensitive ceramic material and its preparation method belong to the field of ceramic material preparation technology. The raw materials used are as follows: yttrium oxide, manganese tetraoxide, chromium oxide and zirconium oxide. The preparation steps are as follows: yttrium oxide, manganese tetraoxide and chromium oxide are mixed and ground to obtain a first slurry, and the first slurry is dried, sieved and calcined to obtain a conductive phase YCr 0.5 Mn 0.5 O3; conductive phase YCr 0.5 Mn 0.5 O3, yttrium oxide and zirconium oxide are mixed and ground to obtain a second slurry, the second slurry is dried and sieved to obtain a second mixture, the second mixture is mixed with a binder to obtain a ceramic powder; the ceramic powder is successively granulated and aged to obtain a pretreated ceramic powder, the pretreated ceramic powder is successively subjected to dry cold isostatic pressing and dried to obtain a ceramic green body; the ceramic green body is sintered at high temperature to obtain the Zr 4+ Doped aY2O3‑bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic material preparation, and specifically relates to a Zr 4+ Doped Y2O3-YCr 0.5 Mn 0.5 O3 thermosensitive ceramic material and preparation method thereof. Background Art

[0002] Negative Temperature Coefficient Thermosensitive Ceramics (NTC) are semiconductor materials with a negative temperature coefficient, whose resistance decreases as the temperature increases. Due to their high sensitivity, high stability, and low cost, NTC thermistors are widely used in the automotive, aviation, and marine industries. The working principle of NTC thermistors is based on the temperature characteristics of semiconductor materials. At room temperature, the resistance of NTC materials is high. As the temperature rises, the concentration of carriers (electrons or holes) in the material increases, causing the resistance to decrease. NTC materials are typically made of metal oxides (such as manganese oxide and nickel oxide), and their resistance characteristics are adjusted through appropriate doping and sintering processes.

[0003] In the existing market, most of the negative temperature coefficient thermistors are spinel structures, and the operating temperature range is from room temperature to 350 ° C, but thermistors with perovskite structures can be used in operating temperatures above 350 ° C, even up to 1000 degrees, and can be better used in high-temperature environments such as the metallurgical industry and automobile exhaust emissions. The perovskite NTC ceramics of the Y-Cr-Mn-O system are used in exhaust gas detection systems in high-temperature environments due to their high precision, high heat resistance and wide detection range. The materials of the Y-Cr-Mn-O system are composed of a high-resistance phase Y2O3 and a semiconductor phase YCr 1-x Mn x O3 composition. YCr 1-x Mn x O3 is a perovskite structure, which is doped with Mn on the basis of YCrO3 perovskite structure. 3+ After the formation, through Mn 3+ The amount of Y2O3 can regulate its resistivity and thermal constant. At the same time, Y2O3 is a rare earth oxide with high resistance, high thermal stability and stable chemical properties. 1-x Mn x O3 compounding can improve the stability of thermal sensitive devices at high temperatures.

[0004] NTC components are small in size and volume. In actual production, ceramic green bodies with larger volumes are usually prepared and then cut and thinned to obtain chips with a thickness of several hundred micrometers. This requires that each small chip obtained has a uniform composition distribution and fewer pores, so that the resistance of each chip is not very different (this is also called the consistency of NTC thermistors), thus meeting the requirements of mass production. The presence of pores will directly affect the change of resistance, resulting in non-uniform resistance values.

[0005] Patent CN115849898A discloses a thermosensitive ceramic material, its preparation method, and a thermistor. This invention provides a body-centered cubic perovskite-like structure CaCu3Ti doped with metal M 12 , with the molecular formula CaCu3Ti 4-x M x O 12 , where M is selected from at least one of Y, Al, Zr, and Mn, and 0 < x ≤ 0.6. By preparing an aqueous solution containing Ca 2+ , Cu 2+ and the doped ion M, the doped ion M is selected from at least one of Y 3+ , Al 3+ , Zr 4 +, Mn 2+ , and preparing a solution containing a Ti 4+ ion complex; mixing and stirring the aqueous solution and the solution containing the Ti 4+ ion complex to obtain a precursor solution; adding a monomer compound and a crosslinking agent to the precursor solution and stirring; continuing to add an initiator to the precursor solution to initiate the polymerization reaction of the monomer compound and the crosslinking agent to obtain a blue gel; drying the blue gel to obtain a dry gel; putting the dry gel into a sintering furnace for roasting, and the sintering furnace is heated from room temperature to 650 °C - 850 °C and kept warm to obtain CaCu3Ti 4-x M x O 12 powder. This CaCu3Ti 4-x M x O 12 thermistor not only has a uniform chemical composition, a narrow particle size distribution of ceramic grains, but also is a compound with a single phase structure, and can well overcome the deficiency of the unsatisfactory product performance consistency caused by the non-uniform chemical composition and non-uniform microstructure of the mixture.

[0006] Patent CN116535203A discloses NTC thermistor ceramics, ceramic chips and preparation methods for rapid temperature measurement of electric water heaters. The invention is made of Co3O4, Mn3O4, NiO, Fe2O3, ZnO, MgO and rare earth element mineral salts. Due to the synergistic effect of MgO and rare earth element mineral salts, the NTC thermistor ceramics have high density, resistance to moisture and heat, and low aging rate.

[0007] Patent CN116813325A discloses a production process for thermosensitive ceramics. The invention involves placing thermosensitive ceramic raw materials separately and sealing them to obtain ready-to-use ingredients. The ready-to-use ingredients are then weighed and mixed to obtain a mixture, which is then ball-milled with water and dried to obtain a ball-milled material. The ball-milled material is sieved and pre-calcined to obtain a pre-calcined material. The mixture is then ball-milled with water to obtain a second abrasive. The second abrasive is statically pressed and sintered to obtain a ceramic core ingot. The ceramic core ingot is cut into ceramic sheets, and silver paste is applied to the surfaces of the sheets, which are then cured and cut to obtain the thermosensitive ceramic. The two grinding steps result in a finer raw material for the thermosensitive ceramic and ensure a more uniform mixing of the raw materials. The preheating treatment further improves the compatibility of the raw material system, enhancing the density of the resulting thermosensitive ceramic and achieving optimal thermal sensitivity.

[0008] NTC ceramics are typically made from metal oxide powders through a process of mixing, molding, and sintering. During this process, the raw materials may contain moisture, volatiles, or gases. These components can form pores during sintering, affecting the consistency of the ceramic. Therefore, improving the consistency of thermistor manufacturing processes is crucial. Summary of the Invention

[0009] Based on the shortcomings of the existing technology, the present invention solves the problems existing in the negative temperature coefficient sintering process and reduces the overall porosity of the thermosensitive ceramic, thereby preparing aY2O3-bYCr with dense microstructure, stable electrical properties and good consistency. 0.5 Mn 0.5 O3 thermosensitive ceramics. Specifically, the technical solution of the present invention includes the following contents:

[0010] One of the purposes of the present invention is to provide a Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermosensitive ceramic material, the Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic materials include the following raw materials:

[0011] Yttrium oxide, manganese tetraoxide, chromium oxide, and zirconium oxide;

[0012] The purity of the yttrium oxide, manganese manganese tetroxide, chromium oxide and zirconium oxide is greater than or equal to 99%.

[0013] The second object of the present invention is to provide a Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 A method for preparing an O3 thermosensitive ceramic material, comprising the following steps:

[0014] Yttrium oxide, manganese tetraoxide and chromium oxide are placed in a ball mill as the first raw material and mixed by grinding balls to obtain a first slurry. The first slurry is dried at 50°C to 120°C and then passed through a 100-mesh sieve to obtain a first mixed material. The first mixed material is calcined at a high temperature of 1000°C to 1300°C for 3h to 5h to obtain a conductive phase YCr 0.5 Mn 0.5 O3;

[0015] The conductive phase YCr 0.5 Mn 0.5 O3, yttrium oxide and zirconium oxide are mixed as the second raw materials in a ball mill with grinding balls for the second time to obtain a second slurry, the second slurry is dried at 50°C to 120°C and then passed through a 100-mesh sieve to obtain a second mixed material, and the second mixed material is mixed with a binder to obtain a ceramic powder;

[0016] The ceramic powder is granulated and aged for 12 to 24 hours to obtain pretreated ceramic powder, which is then subjected to dry cold isostatic pressing and dried to obtain a ceramic green body; the ceramic green body is sintered at a high temperature of 1550 to 1650 degrees Celsius for 3 to 5 hours to obtain the Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0017] Furthermore, the molar ratio of Y:Cr:Mn of yttrium oxide, manganese tetraoxide and chromium oxide in the first raw material is 2:1:1.

[0018] Furthermore, the conditions for the first ball milling mixing include that the ball milling medium is anhydrous ethanol, the mass ratio of the first raw material: the ball milling medium: the grinding balls is 1:1-4:0.8-2.5, and the ball milling time is 8h-36h.

[0019] Furthermore, the conductive phase YCr 0.5 Mn 0.5 The molar ratio of O3:yttria:zirconia is 0.4:0.6:0-0.15.

[0020] Preferably, the conductive phase YCr 0.5 Mn 0.5The molar ratio of O3:yttria:zirconia is 0.4:0.6:0.03-0.12.

[0021] Furthermore, the conditions for the second ball milling mixing include that the ball milling medium is anhydrous ethanol, the mass ratio of the second raw material: the ball milling medium: the grinding balls is 1:1-4:0.8-2.5, and the ball milling time is 8h-36h.

[0022] Furthermore, the binder is polyvinyl alcohol with a mass concentration of 5%.

[0023] Furthermore, the mass ratio of the second mixture to the binder is 1:0.05 to 0.15.

[0024] Furthermore, the conditions of the dry cold isostatic pressing include a molding pressure of 20 MPa to 30 MPa and a holding time of 30 s to 180 s.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The thermal ceramics in the present invention are mainly composed of high resistance phase Y2O3 and conductive phase YCr 0.5 Mn 0.5 O3, while the doped ZrO2 is mainly located in the Y2O3 phase (Y 1-x Zr x )2O3 solid solution. The addition of ZrO2 reduces the melting point of the ZrO2-Y2O3 binary system and reduces the sintering temperature. 4+ Radius With Y 3+ Radius Similar, this ensures that Zr 4+ Replace Y 3+ The lattice distortion is small. In the final stage of sintering, a part of the grains with low surface energy tend to grow to a larger size at the consumption of the surrounding smaller grains, which is called discontinuous grain growth. In this process, due to the high mobility of the grain boundaries, the pores are easily enclosed in the grains, and the sintering is no longer densified. Since ZrO2 has a high melting point (2715℃), it is easy to form a solid solution at the grain boundaries, and has a lower grain boundary migration speed than Y2O3, thereby hindering the migration of grain boundaries and the occurrence of secondary recrystallization, which is conducive to eliminating pores and uniform grain size, and improving the consistency of negative temperature coefficient thermistors.

[0027] (2) The raw materials used for the thermosensitive ceramic material in the present invention are all common oxides, and the preparation process is simple and the cost is low.

[0028] (3) Zr doping 4+ aY2O3-bYCr 0.5 Mn 0.5O3 thermistor ceramic materials have high density, excellent electrical properties, and greatly improved consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The XRD patterns of the samples in Examples 1-6 are shown in FIG.

[0030] Figure 2 The SEM images of the samples in Examples 1-6 are shown. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions of the present invention through the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0033] Yttrium oxide (Y2O3): purchased from Aladdin, purity ≥99.9%, CAS number 1314-36-9;

[0034] Chromium oxide (Cr2O3): purchased from Aladdin, purity ≥99.9%, CAS number 1333-82-0;

[0035] Manganese tetraoxide (Mn3O4): purchased from Aladdin, purity ≥99.9%, CAS number 1317-35-7;

[0036] Zirconium oxide (ZrO2): Purchased from Aladdin, purity ≥99.9%, CAS number 1314-23-4.

[0037] Example 1:

[0038] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O 33 The preparation of thermosensitive ceramic materials specifically includes the following processes:

[0039] First batching: Using an electronic analytical balance with an accuracy of 0.0001 g, Y2O3, Cr2O3 and Mn3O4 were weighed as the first raw material according to the pre-designed molar ratio of Y:Cr:Mn of 2:1:1.

[0040] First Mixing: The weighed first raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:1:0.8. The milling speed was set at 300 r / min and the milling time was controlled to be 8 hours. After milling, the resulting first slurry was placed in a drying oven and dried at 50°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain a uniform first mixed material.

[0041] Calcination: The first mixture was calcined at 1000 ° C for 3 hours to obtain the conductive phase YCr 0.5 Mn 0.5 O3.

[0042] Second batching: Use an electronic analytical balance with an accuracy of 0.0001g, according to the conductive phase YCr 0.5 Mn 0.5 The formula ratio of O3:Y2O3 molar ratio is 0.4:0.6. The molar weight of the conductive phase YCr 0.5 Mn 0.5 O3 and Y2O3 are used as the second raw materials.

[0043] Second Mixing: The weighed second raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:1:0.8. The milling speed was set at 300 r / min and the milling time was controlled to be 8 hours. After ball milling, the resulting second slurry was placed in a drying oven and dried at 50°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain the second mixed material.

[0044] Granulation and aging: A homemade 5% polyvinyl alcohol (PVA) solution (5% by mass, based on the weight of the second mixture) was added to the sieved second mixture as a binder and thoroughly mixed in an agate mortar to produce a ceramic powder. The mixed ceramic powder was then granulated on a tray and aged for 12 hours to improve its molding properties, thereby producing a pretreated ceramic powder.

[0045] Molding and Drying: Weigh a certain amount of pre-treated ceramic powder that has been aged and placed in a stainless steel mold. Form the ceramic body using dry cold isostatic pressing, maintaining a molding pressure of 20 MPa and a holding time of 30 seconds. Place the resulting ceramic body in a drying oven at 100°C for 24 hours until the quality stabilizes.

[0046] Firing: The dried ceramic body was placed in a muffle furnace and sintered in air atmosphere. The temperature was raised to 1200℃ at a heating rate of 3℃ / min, and then the heating rate was adjusted to 1℃ / min and the temperature was raised to 1550℃. The holding time was 3 hours, and the ceramic body was cooled in the furnace to obtain Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0047] Example 2:

[0048] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0049] First batching: Using an electronic analytical balance with an accuracy of 0.0001 g, Y2O3, Cr2O3 and Mn3O4 were weighed as the first raw material according to the pre-designed molar ratio of Y:Cr:Mn of 2:1:1.

[0050] First Mixing: The weighed first raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:1.5:1.5, the milling speed was set at 300 r / min, and the milling time was controlled to be 12 hours. After milling, the resulting first slurry was placed in a drying oven and dried at 90°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain a uniform first mixed material.

[0051] Calcination: The first mixture was calcined at 1100°C for 4 hours to obtain the conductive phase YCr 0.5 Mn 0.5 O3.

[0052] Second batching: Use an electronic analytical balance with an accuracy of 0.0001g, according to the conductive phase YCr 0.5 Mn 0.5 The formula ratio of O3:Y2O3:ZrO2 is 0.4:0.6:0.03. The conductive phase YCr is weighed in moles. 0.5 Mn 0.5 O3, Y2O3 and ZrO2 serve as the second raw materials.

[0053] Second Mixing: The weighed second raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:1.5:1.5, the milling speed was set at 300 rpm, and the milling time was controlled to be 12 hours. After milling, the resulting second slurry was placed in a drying oven and dried at 90°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain the second mixed material.

[0054] Granulation and aging: A homemade 5% polyvinyl alcohol (PVA) solution (10% by mass, representing 10% of the second mixture's mass) was added to the sieved second mixture as a binder and thoroughly mixed in an agate mortar to produce a ceramic powder. The mixed ceramic powder was then granulated on a tray and aged for 24 hours to improve its molding properties, thereby producing a pretreated ceramic powder.

[0055] Molding and Drying: Weigh a certain amount of pre-treated ceramic powder that has undergone aging treatment and place it into a stainless steel mold. Press the mold using dry cold isostatic pressing, maintaining a molding pressure of 24 MPa and a holding time of 60 seconds. The resulting ceramic body is then dried in a drying oven at 100°C for 24 hours until the quality stabilizes.

[0056] Firing: The dried ceramic body was placed in a muffle furnace and sintered in air atmosphere. The temperature was raised to 1200℃ at a heating rate of 3℃ / min, and then the heating rate was adjusted to 1℃ / min to the firing temperature of 1600℃. The holding time was 4 hours, and the ceramic body was cooled in the furnace to obtain Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0057] Example 3:

[0058] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0059] First batching: Using an electronic analytical balance with an accuracy of 0.0001 g, Y2O3, Cr2O3 and Mn3O4 were weighed as the first raw material according to the pre-designed molar ratio of Y:Cr:Mn of 2:1:1.

[0060] First Mixing: The weighed first raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:2.5:2. The milling speed was set at 300 r / min and the milling time was controlled to be 24 hours. After milling, the resulting first slurry was placed in a drying oven and dried at 100°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain a uniform first mixed material.

[0061] Calcination: The first mixture was calcined at 1200 ° C for 5 hours to obtain the conductive phase YCr 0.5 Mn 0.5 O3.

[0062] Second batching: Use an electronic analytical balance with an accuracy of 0.0001g, according to the conductive phase YCr 0.5 Mn 0.5 The formula ratio of O3:Y2O3:ZrO2 is 0.4:0.6:0.06. The conductive phase YCr is weighed in moles. 0.5 Mn 0.5 O3, Y2O3 and ZrO2 serve as the second raw materials.

[0063] Second Mixing: The weighed second raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:2.5:2. The milling speed was set at 300 r / min and the milling time was controlled to be 24 hours. After ball milling, the resulting second slurry was placed in a drying oven and dried at 100°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain the second mixed material.

[0064] Granulation and aging: A homemade 5% polyvinyl alcohol (PVA) solution (10% by mass, representing 10% of the second mixture's mass) was added to the sieved second mixture as a binder and thoroughly mixed in an agate mortar to produce a ceramic powder. The mixed ceramic powder was then granulated on a tray and aged for 24 hours to improve its molding properties, thereby producing a pretreated ceramic powder.

[0065] Molding and Drying: Weigh a certain amount of pre-treated ceramic powder that has undergone aging treatment and place it into a stainless steel mold. Press the mold using dry cold isostatic pressing, maintaining a molding pressure of 28 MPa and a holding time of 120 seconds. The resulting ceramic body is then dried in a drying oven at 100°C for 24 hours until the quality stabilizes.

[0066] Firing: The dried ceramic body was placed in a muffle furnace and sintered in air atmosphere. The temperature was raised to 1200℃ at a heating rate of 3℃ / min, and then the heating rate was adjusted to 1℃ / min to the firing temperature of 1600℃. The holding time was 5 hours, and the ceramic body was cooled in the furnace to obtain Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0067] Example 4:

[0068] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0069] First batching: Using an electronic analytical balance with an accuracy of 0.0001 g, Y2O3, Cr2O3 and Mn3O4 were weighed as the first raw material according to the pre-designed molar ratio of Y:Cr:Mn of 2:1:1.

[0070] First Mixing: The weighed first raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:4:2.5. The milling speed was set at 300 r / min and the milling time was controlled to be 36 hours. After milling, the resulting first slurry was placed in a drying oven and dried at 120°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain a uniform first mixed material.

[0071] Calcination: The first mixture was calcined at 1300 ° C for 5 hours to obtain the conductive phase YCr 0.5 Mn 0.5 O3.

[0072] Second batching: Use an electronic analytical balance with an accuracy of 0.0001g, according to the conductive phase YCr 0.5 Mn 0.5 The formula ratio of O3:Y2O3:ZrO2 is 0.4:0.6:0.09. The conductive phase YCr is weighed in moles. 0.5 Mn 0.5 O3, Y2O3 and ZrO2 serve as the second raw materials.

[0073] Second Mixing: The weighed second raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:4:2.5. The milling speed was set at 300 r / min and the milling time was controlled to be 36 hours. After milling, the resulting second slurry was placed in a drying oven and dried at 120°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain the second mixed material.

[0074] Granulation and aging: A homemade 5% polyvinyl alcohol (PVA) solution (15% by mass, representing 15% of the second mixture's mass) was added to the sieved second mixture as a binder and thoroughly mixed in an agate mortar to produce a ceramic powder. The mixed ceramic powder was then granulated on a tray and aged for 24 hours to improve its molding properties, thereby producing a pretreated ceramic powder.

[0075] Molding and Drying: Weigh a certain amount of pre-treated ceramic powder that has undergone aging treatment and place it into a stainless steel mold. Press the mold using dry cold isostatic pressing, maintaining a molding pressure of 30 MPa and a holding time of 180 seconds. The resulting ceramic body is then dried in a drying oven at 100°C for 24 hours until the quality stabilizes.

[0076] Firing: The dried ceramic body was placed in a muffle furnace and sintered in air atmosphere. The temperature was raised to 1200℃ at a heating rate of 3℃ / min, and then the heating rate was adjusted to 1℃ / min to the firing temperature of 1650℃. The holding time was 5 hours, and the ceramic body was cooled in the furnace to obtain Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0077] Example 5:

[0078] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0079] First batching: Using an electronic analytical balance with an accuracy of 0.0001 g, Y2O3, Cr2O3 and Mn3O4 were weighed as the first raw material according to the pre-designed molar ratio of Y:Cr:Mn of 2:1:1.

[0080] First Mixing: The weighed first raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:4:2.5. The milling speed was set at 300 r / min and the milling time was controlled to be 36 hours. After milling, the resulting first slurry was placed in a drying oven and dried at 120°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain a uniform first mixed material.

[0081] Calcination: The first mixture was calcined at 1300 ° C for 5 hours to obtain the conductive phase YCr 0.5 Mn 0.5 O3.

[0082] Second batching: Use an electronic analytical balance with an accuracy of 0.0001g, according to the conductive phase YCr 0.5 Mn 0.5 The formula ratio of O3:Y2O3:ZrO2 is 0.4:0.6:0.12. The conductive phase YCr is weighed in moles. 0.5 Mn 0.5 O3, Y2O3 and ZrO2 serve as the second raw materials.

[0083] Second Mixing: The weighed second raw material was placed in an XGB2 planetary ball mill and milled and mixed using anhydrous ethanol as the milling medium. The mass ratio of the first raw material, milling medium, and grinding balls was controlled to be 1:4:2.5. The milling speed was set at 300 r / min and the milling time was controlled to be 36 hours. After milling, the resulting second slurry was placed in a drying oven and dried at 120°C for 12 hours. The dried powder was sieved through a 100-mesh sieve to obtain the second mixed material.

[0084] Granulation and aging: A homemade 5% polyvinyl alcohol (PVA) solution (15% by mass, representing 15% of the second mixture's mass) was added to the sieved second mixture as a binder and thoroughly mixed in an agate mortar to produce a ceramic powder. The mixed ceramic powder was then granulated on a tray and aged for 24 hours to improve its molding properties, thereby producing a pretreated ceramic powder.

[0085] Molding and Drying: Weigh a certain amount of pre-treated ceramic powder that has undergone aging treatment and place it into a stainless steel mold. Press the mold using dry cold isostatic pressing, maintaining a molding pressure of 30 MPa and a holding time of 180 seconds. The resulting ceramic body is then dried in a drying oven at 100°C for 24 hours until the quality stabilizes.

[0086] Firing: The dried ceramic body was placed in a muffle furnace and sintered in air atmosphere. The temperature was raised to 1200℃ at a heating rate of 3℃ / min, and then the heating rate was adjusted to 1℃ / min to the firing temperature of 1650℃. The holding time was 5 hours, and the ceramic body was cooled in the furnace to obtain Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

[0087] Example 6:

[0088] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0089] The amount of zirconium oxide in Example 4 was increased from 0.09 mol to 0.15 mol, and the other conditions remained the same as in Example 4.

[0090] Comparative Example 1:

[0091] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0092] The conductive phase YCr in Example 1 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 1.

[0093] Comparative Example 2:

[0094] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0095] The conductive phase YCr in Example 2 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 2.

[0096] Comparative Example 3:

[0097] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0098] The conductive phase YCr in Example 3 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 3.

[0099] Comparative Example 4:

[0100] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0101] The conductive phase YCr in Example 4 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 4.

[0102] Comparative Example 5:

[0103] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0104] The conductive phase YCr in Example 5 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 5.

[0105] Comparative Example 6:

[0106] A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0107] The conductive phase YCr in Example 6 0.5 Mn 0.5 The O3:Y2O3 molar ratio was adjusted from 0.4:0.6 to 0.3:0.7, and the other conditions remained the same as in Example 6.

[0108] Comparative Example 7:

[0109] A Ca 2+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0110] The zirconium oxide in Example 3 was replaced by calcium oxide, and the other conditions remained the same as in Example 3.

[0111] Comparative Example 8:

[0112] A Sr 2+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation of O3 thermistor ceramic materials specifically includes the following processes:

[0113] The zirconium oxide in Example 3 was replaced by strontium oxide, and the other conditions remained the same as in Example 3.

[0114] Detection of Zr obtained in Examples 1 to 6 and Comparative Examples 1 to 6 4+ Doped Y2O3-YCr 0.5 Mn 0.5 O3 thermosensitive ceramic material, Ca obtained in Comparative Example 7 2+ Doped Y2O3-YCr 0.5 Mn 0.5 O3 thermosensitive ceramic material and Sr obtained in Comparative Example 8 2+ Doped aY2O3-bYCr 0.5 Mn 0.5 The resistivity, B25 / 50 value, density and consistency of the O3 thermistor ceramic material are shown in Table 1 below.

[0115] Table 1

[0116]

[0117] From the test data in Table 1, we can find that:

[0118] (1) Within the scope of the formula designed by the present invention, the Zr obtained in Examples 1 to 5 4+ Doped Y2O3-YCr 0.5 Mn 0.5 O3 thermistor ceramic material has low resistivity and good consistency improvement.

[0119] (2) It can be seen from Example 6 that when the amount of zirconium oxide is further increased, the resistivity is greatly improved, and the consistency is significantly reduced, which is not conducive to the Y2O3-YCr 0.5 Mn 0.5 The consistency of O3 thermistor ceramic materials is improved.

[0120] (3) Comparative Examples 1 to 6 show that when the conductive phase YCr is reduced 0.5 Mn 0.5When the usage of O3 is increased and the usage of Y2O3 is increased, zirconium doping can still improve the consistency of the thermistor ceramic, but the resistivity of the thermistor ceramic is relatively high. Similarly, when the usage of zirconium oxide is further increased (Comparative Example 6), the consistency of the thermistor ceramic is reduced, which is not conducive to improving the consistency of the thermistor ceramic.

[0121] (4) According to Comparative Example 7, small atoms Ca 2+ The doping effect of Zr in the formulation process system of the present invention is much lower than that of Zr with the same size. 4+ doping effect.

[0122] (5) Comparative Example 8 shows that due to the high grain boundary migration rate of strontium oxide, it is easy to produce closed pores at the grain boundaries after doping, which has adverse effects on the performance of the thermosensitive ceramic, resulting in poor consistency of the thermosensitive ceramic finally prepared.

[0123] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermosensitive ceramic material, characterized in that The Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic materials include the following raw materials: Yttrium oxide, manganese tetraoxide, chromium oxide, and zirconium oxide; The purity of the yttrium oxide, manganese oxide, chromium oxide and zirconium oxide is ≥99%; The Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 Zr in O3 thermal sensitive ceramic materials 4+ The molar percentage is 3%~15%; The Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 In the O3 thermistor ceramic material, a is 0.6 and b is 0.

4.

2. A Zr as claimed in claim 1 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 The preparation method of O3 thermosensitive ceramic material is characterized in that: The preparation method comprises the following steps: Yttrium oxide, manganese oxide and chromium oxide are placed in a ball mill as the first raw material and mixed by grinding balls to obtain a first slurry. The first slurry is dried at 50°C to 120°C and then passed through a 100-mesh sieve to obtain a first mixed material. The first mixed material is calcined at a high temperature of 1000°C to 1300°C for 3h to 5h to obtain a conductive phase YCr 0.5 Mn 0.5 O3; The conductive phase YCr 0.5 Mn 0.5 O3, yttrium oxide and zirconium oxide are used as the second raw materials and mixed by a second ball mill in a ball mill with grinding balls to obtain a second slurry, the second slurry is dried at 50°C to 120°C and then passed through a 100-mesh sieve to obtain a second mixed material, and the second mixed material is mixed with a binder to obtain a ceramic powder; The ceramic powder is granulated and aged for 12 hours to 24 hours to obtain a pretreated ceramic powder, and the pretreated ceramic powder is dry cold isostatically pressed and dried to obtain a ceramic green body; the ceramic green body is sintered at a high temperature of 1550° C. to 1650° C. for 3 hours to 5 hours to obtain the Zr 4+ Doped aY2O3-bYCr 0.5 Mn 0.5 O3 thermistor ceramic material.

3. The preparation method according to claim 2, characterized in that The molar ratio of Y:Cr:Mn among yttrium oxide, trimanganese tetraoxide and chromium oxide in the first raw material is 2:1:

1.

4. The preparation method according to claim 2, characterized in that The conditions for the first ball milling mixing include using anhydrous ethanol as the ball milling medium, a mass ratio of the first raw material: the ball milling medium: the grinding balls being 1:1-4:0.8-2.5, and a ball milling time of 8h-36h.

5. The preparation method according to claim 2, characterized in that The conductive phase YCr 0.5 Mn 0.5 The molar ratio of O3: yttria: zirconium oxide is 0.4: 0.6: 0.03~0.

15.

6. The preparation method according to claim 2, characterized in that The conditions for the second ball milling mixing include using anhydrous ethanol as the ball milling medium, a mass ratio of the second raw material: the ball milling medium: the grinding balls being 1:1-4:0.8-2.5, and a ball milling time of 8h-36h.

7. The preparation method according to claim 2, characterized in that The binder is polyvinyl alcohol with a mass concentration of 5%.

8. The preparation method according to claim 2, characterized in that The mass ratio of the second mixture to the binder is 1:0.05-0.

15.

9. The preparation method according to claim 2, characterized in that The conditions for the dry cold isostatic pressing include a molding pressure of 20 MPa to 30 MPa and a holding time of 30 s to 180 s.

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