Luminous ZnO-Bi2O3-based voltage-sensitive ceramic material and preparation method thereof
By introducing fluorescent materials ZnO and Er2O3 into ZnO-Bi2O3-based varistor ceramics and combining them with solid-state sintering of MnO2, Sb2O3 and Bi2O3, a multifunctional varistor ceramic with both luminescence and varistor properties was prepared. This solved the problem of insufficient fluorescence performance in the existing technology, achieved excellent coexistence of electrical and luminescence properties, and expanded its application range.
Patent Information
- Application Number
- CN202511228034.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-10-21
AI Technical Summary
Existing ZnO-Bi2O3-based varistors, after being doped with rare earth ions, suffer from insufficient fluorescence performance due to the formation of a bismuth-rich phase by bismuth oxide and grain boundary defects, thus failing to exhibit significant photoluminescence properties.
By introducing fluorescent materials ZnO and Er2O3 into ZnO-Bi2O3-based varistor ceramics, luminescent varistor ceramics are prepared by solid-state sintering. MnO2, Sb2O3 and Bi2O3 are combined as varistor modifiers to form fluorescent centers and regulate the microstructure, achieving the coexistence of luminescence and varistor properties.
A multifunctional pressure-sensitive ceramic sheet with both luminescence and pressure-sensitive properties was prepared, with a nonlinear coefficient α as high as 50.18 and an orange-red luminescence color, expanding its application in anti-counterfeiting and marking, intelligent sensing and indication, etc.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of varistor ceramics, and in particular relates to a luminescent ZnO-Bi2O3 based varistor ceramic material and a preparation method thereof. Background Art
[0002] ZnO-Bi2O3 based varistors have been widely studied and applied in power systems, communication equipment, household appliances and other fields as devices for surge absorption, overvoltage suppression and voltage stabilization due to their excellent nonlinear volt-ampere characteristics and surge absorption capacity. In recent years, people have mainly devoted themselves to the optimization of synthesis schemes and performance regulation of ZnO-Bi2O3 based varistor ceramics to meet the ever-changing industrial needs. For example, Xu et al. studied the microstructure and electrical response of ZnO-Bi2O3 based varistor ceramics at different temperatures and different sintering processes; Zhang et al. studied the effect of erbium oxide doping on the microstructure and electrical properties of ZnO-Bi2O3 based varistors. The results showed that when the erbium oxide doping concentration was 0.4 mol%, the microstructure of the varistor became more uniform, and the varistor field strength (E 1mA ) also improved, with its nonlinear coefficient α reaching 48. With the development of new energy vehicles, smart homes and other fields, ZnO-Bi2O3-based varistor ceramics are gradually iterating towards miniaturization and multifunctional integration.
[0003] The rare earth element Erbium is expected to give varistor ceramics new luminescence properties and improve their electrical properties due to its excellent luminescence properties, which provides the possibility for the preparation of luminescent and multifunctional ZnO-Bi2O3 based varistor ceramic materials. However, in the current research reports on the photoluminescence properties of rare earth ion doped varistor ceramics, on the one hand, due to the formation of bismuth-rich phase during the sintering process of bismuth oxide, most of the rare earth ions exist in the bismuth-rich phase, such as (Bi 0.75 Er 0.25 )2O3, causing concentration quenching and reducing the rare earth ions that can enter the main phase zinc oxide to form fluorescent centers. On the other hand, due to the high types and concentrations of defects in the varistor ceramics, especially near the grain boundaries, non-radiative relaxation is enhanced, causing the excitation energy to be dissipated, and therefore no fluorescent performance can be exhibited. Summary of the Invention
[0004] In order to solve the above problems, the present invention provides a luminescent ZnO-Bi2O3-based varistor ceramic material and a preparation method thereof, which introduces luminescent centers into the ZnO-Bi2O3-based varistor ceramic, giving the material fluorescent properties while retaining the microstructure and properties of the matrix, thereby expanding the potential applications of the varistor ceramic in anti-counterfeiting and identification, intelligent sensing and indication, etc.
[0005] In order to achieve the above object, the specific technical solutions provided by the present invention are as follows: The first object of the present invention is to provide a luminescent ZnO-Bi2O3-based varistor ceramic material, which is prepared by solid-phase sintering of a varistor-modifying material and a fluorescent material, the molar ratio of the varistor-modifying material and the fluorescent material being 1.8 to 2.8:100, the varistor-modifying material being MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 being 0.5:0.5:0.8 to 2.8; the fluorescent material being ZnO and Er2O3, and the doping concentration of Er2O3 in the fluorescent material being 0.2 mol% to 0.6 mol%.
[0006] Furthermore, the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:1.6~2.4.
[0007] Furthermore, the method for preparing the fluorescent material comprises the following steps: S1. According to the composition ratio of the fluorescent material, weigh ZnO and Er2O3 raw materials and mix them to form a fluorescent mixture.
[0008] S2. Adding ball milling medium to the fluorescent mixture, ball milling, drying to obtain a uniform powder, and solid-phase sintering the uniform powder to obtain a fluorescent material.
[0009] Furthermore, the ball milling time is 6 hours to 10 hours, the rotation speed is 250 rpm to 350 rpm, the solid phase sintering temperature is 1000° C. to 1200° C., and the time is 2 hours to 4 hours.
[0010] A second object of the present invention is to provide a method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material, comprising the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials and mix them to form a pressure-sensitive modified mixture.
[0011] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material, add ball milling media, perform ball milling, dry to obtain a mixed powder, add a binder to the mixed powder, granulate and then mold into a green body.
[0012] Step 3: calcining the green body to remove binder, and then solid-phase sintering to obtain ZnO-Bi2O3 based varistor ceramic material.
[0013] Furthermore, the amount of the binder is 1 wt.% to 3 wt.% of the total amount of the mixed powder. The binder is a polyvinyl alcohol aqueous solution, and the concentration of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 7 wt.% to 10 wt.%.
[0014] Furthermore, the calcination temperature is 550° C. to 650° C., and the holding time is 4 h to 6 h.
[0015] Furthermore, the solid phase sintering temperature is 950° C. to 1100° C., and the time is 2 h to 4 h.
[0016] Furthermore, the ball milling time is 6 h to 10 h, and the rotation speed is 250 rpm to 350 rpm.
[0017] Compared with the prior art, the beneficial effects of the present invention are: The ZnO-Bi2O3-based varistor ceramic material provided by the present invention uses ZnO and Er2O3 to form a fluorescent material. By introducing the fluorescent material into the ZnO-Bi2O3-based varistor ceramic, the material is endowed with fluorescent properties while retaining the microstructure and properties of the matrix. The doping process achieves secondary regulation of the varistor ceramic properties, so that the material has fluorescent properties while exhibiting excellent varistor properties. The prepared multifunctional varistor ceramic sheet with luminescence and varistor properties has an orange-red upconversion spectrum and a nonlinear coefficient α of up to 50.18, achieving the coexistence of electrical and luminescence properties. This provides potential application directions for varistor ceramics in anti-counterfeiting and identification, intelligent sensing and indication, etc., which greatly expands the application range of the material in new integrated electro-optical and multifunctional devices.
[0018] The fluorescent material provided by the present invention is pre-synthesized through a preliminary solid-phase sintering process, first imparting excellent luminescence properties to the material, exhibiting red upconversion luminescence. The varistor material is then mixed with the fluorescent material and subjected to a secondary solid-phase sintering process to produce a ZnO-Bi2O3-based varistor ceramic with luminescence. This method imparts fluorescent properties to the material while preserving the microstructure and properties of the matrix. High-temperature sintering allows diffusion and bonding between the powder particles, ultimately forming a densified structure. The preparation method is simple, stable, and controllable. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The luminescence performance of the ZE phosphor prepared in Example 1 of the present invention.
[0020] Figure 2 This is the XRD analysis spectrum of the varistor ceramic materials prepared in Examples 2 to 7 of the present invention and Comparative Example 1.
[0021] Figure 3 The scanning electron microscope analysis spectrum of the piezoresistive ceramic materials prepared in Examples 2 to 7 of the present invention and Comparative Example 1 is shown. Figure 3 (a) is Comparative Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, (e) is Example 5, (f) is Example 6, (g) is Example 7, and (h) is the average grain size.
[0022] Figure 4 This is a graph showing the luminescence performance of the piezoresistive ceramic materials of Examples 3, 5 and 7 of the present invention. Figure 4 (a) is the upconversion luminescence spectrum, and (b) is the fluorescence decay curve spectrum.
[0023] Figure 5 is the CIE chromaticity spectrum of the varistor ceramic material of the present invention.
[0024] Figure 6 This is an EJ curve obtained by testing the varistor ceramic materials prepared in Examples 2 to 7 of the present invention and Comparative Example 1 after coating the electrodes.
[0025] Figure 7 CV curves obtained by testing the electrodes coated with the varistor ceramic materials prepared in Examples 2 to 7 of the present invention and Comparative Example 1. DETAILED DESCRIPTION
[0026] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings, but the embodiments are not intended to limit the present invention.
[0027] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.
[0028] The present invention provides a luminescent ZnO-Bi2O3-based varistor ceramic material, which is prepared by solid-phase sintering a varistor-modified material and a fluorescent material. The molar ratio of the varistor-modified material to the fluorescent material is 1.8-2.8:100. The varistor-modified material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:0.8-2.8. The fluorescent material comprises ZnO and Er2O3, and the doping concentration of Er2O3 in the fluorescent material is 0.2 mol%-0.6 mol%. In some preferred embodiments, the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:1.6-2.4, and the molar ratio of ZnO and Er2O3 is 0.5:0.5:1.6-2.4. 33 The molar ratio of Er2O3 is 99.5:0.5, and the high doping concentration of Er2O3 in the fluorescent material will affect the luminescence performance.
[0029] In the present invention, a ZnO-Bi2O3-based varistor ceramic material is provided, in which a fluorescent material is formed from ZnO and Er2O3. By introducing the fluorescent material into the ZnO-Bi2O3-based varistor ceramic, secondary regulation of the performance of the varistor ceramic is achieved through a doping process, so that the material has fluorescent properties while exhibiting excellent varistor performance. The upconversion spectrum of the prepared luminescent multifunctional varistor ceramic sheet is orange-red, and the nonlinear coefficient α is as high as 50.18, achieving the coexistence of electrical and luminescent properties, and providing potential application directions for varistor ceramics in anti-counterfeiting and identification, intelligent sensing and indication, etc., which greatly expands the application range of the material in new integrated electro-optical and multifunctional devices.
[0030] In some preferred embodiments, the method for preparing the fluorescent material comprises the following steps: S1. According to the composition ratio of the fluorescent material, weigh ZnO and Er2O3 raw materials and mix them to form a fluorescent mixture.
[0031] S2. Add ball milling medium to the fluorescent mixture, ball mill at a rotation speed of 250 rpm to 350 rpm for 6 hours to 10 hours, obtain uniform powder after drying, and solid-phase sinter the uniform powder at 1000° C. to 1200° C. for 3 hours to 5 hours to obtain the fluorescent material.
[0032] The present invention also provides a method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material, comprising the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials and mix them to form a pressure-sensitive modified mixture.
[0033] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material, add ball milling media, and perform ball milling at a speed of 250 rpm to 350 rpm for 6 hours to 10 hours. After drying, a mixed powder is obtained. A binder is added to the mixed powder, and the mixed powder is granulated and molded into a green body.
[0034] Step 3: calcining the green body at 550 to 650 hours to remove binder for 2 hours, and then solid-phase sintering at 950° C. to 1100° C. to obtain a ZnO-Bi2O3-based varistor ceramic material.
[0035] In this invention, conventional solid-phase sintering is used to prepare fluorescent materials and ZnO-Bi2O3-based varistor ceramics. A preliminary solid-phase sintering presynthesis method first imparts excellent luminescence properties to the material, resulting in a red upconversion luminescence color. The varistor and fluorescent materials are then mixed and subjected to a secondary solid-phase sintering process to produce a ZnO-Bi2O3-based varistor ceramic with luminescence. This method imparts fluorescent properties to the material while preserving the microstructure and properties of the matrix. A densified structure is formed by diffusion and bonding between powder particles at high temperatures. The preparation method is simple, stable, and controllable.
[0036] In some preferred embodiments, the amount of the binder is 1 wt.% to 3 wt.% of the total amount of the mixed powder. The binder is a polyvinyl alcohol aqueous solution, and the concentration of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 7 wt.% to 10 wt.%.
[0037] The following is further described through specific examples.
[0038] Example 1 A fluorescent material comprises ZnO and Er2O3, wherein the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0039] The preparation method of the fluorescent material comprises the following steps: S1. According to the composition ratio of the fluorescent material, weigh ZnO and Er2O3 raw materials at a ratio of 99.5 mol% ZnO: 0.5 mol% Er2O3, and mix them to form a fluorescent mixture.
[0040] S2. Add anhydrous ethanol ball milling medium to the fluorescent mixture. The ratio of the fluorescent mixture to anhydrous ethanol is 1 g:1.5 mL. Ball milling is carried out at a rotation speed of 300 rpm for 8 h. The ball-to-material ratio during the ball milling process is 10:1 to obtain ball milling slurry. The ball milling slurry is placed in an oven for drying to obtain a fluorescent mixture.
[0041] S3. The fluorescent mixture is placed in a muffle furnace for solid-phase sintering. The temperature is raised to 1075°C at a heating rate of 3°C / min and kept at this temperature for 4 hours to obtain a fluorescent material named ZE phosphor.
[0042] The luminescence performance of the ZE phosphor prepared in Example 1 was tested using fluorescence spectroscopy. Figure 1 The luminescence performance of the ZE phosphor in Example 1 of the present invention is shown in FIG. Figure 1 As shown, the upconversion luminescence color of the ZE phosphor is red.
[0043] Example 2 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 1.8:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:0.8; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0044] The preparation method of the fluorescent material is the same as that in Example 1.
[0045] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 0.8mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0046] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 1.8 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0047] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0048] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sintering for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-0.8B.
[0049] Example 3 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 2.2:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:1.2; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0050] The preparation method of the fluorescent material is the same as that in Example 1.
[0051] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 1.2mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0052] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 2.2 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0053] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0054] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-1.2B.
[0055] Example 4 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 2.6:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:1.6; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0056] The preparation method of the fluorescent material is the same as that in Example 1.
[0057] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 1.6mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0058] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 2.6 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0059] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0060] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter it for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-1.6B.
[0061] Example 5 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 3.0:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:2.0; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0062] The preparation method of the fluorescent material is the same as that in Example 1.
[0063] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 2.0mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0064] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 3.0 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0065] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0066] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-2.0B.
[0067] Example 6 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 3.4:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:2.4; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0068] The preparation method of the fluorescent material is the same as that in Example 1.
[0069] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 2.4mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0070] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 3.4 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0071] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0072] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-2.0B.
[0073] Example 7 A luminescent ZnO-Bi2O3-based varistor ceramic material is prepared by solid-phase sintering a varistor-modifying material and a fluorescent material, wherein the molar ratio of the varistor-modifying material to the fluorescent material is 3.8:100, the varistor-modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:2.8; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0074] The preparation method of the fluorescent material is the same as that in Example 1.
[0075] The method for preparing the above-mentioned luminescent ZnO-Bi2O3-based varistor ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2, Sb2O3 and Bi2O3 raw materials at a feeding ratio of 0.5mol% MnO2: 0.5mol% Sb2O3: 2.8mol% Bi2O3, and mix them to form a pressure-sensitive modified mixture.
[0076] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 3.8 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0077] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0078] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and calcine for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter for 2 hours to obtain a ZnO-Bi2O3-based varistor ceramic material, named ZE-MS-2.8B.
[0079] Comparative Example 1 A luminescent piezoresistive ceramic material is prepared by solid-phase sintering a piezoresistive modifying material and a fluorescent material, wherein the molar ratio of the piezoresistive modifying material to the fluorescent material is 1.8:100, the piezoresistive modifying material comprises MnO2 and Sb2O3, and the molar ratio of MnO2 to Sb2O3 is 0.5:0.5; and the fluorescent material comprises ZnO and Er2O3, and the molar ratio of ZnO to Er2O3 is 99.5:0.5.
[0080] The preparation method of the fluorescent material is the same as that in Example 1.
[0081] The method for preparing the above-mentioned luminescent pressure-sensitive ceramic material comprises the following steps: Step 1: According to the composition ratio of the pressure-sensitive modified material, weigh MnO2 and Sb2O3 raw materials at a feeding ratio of 0.5 mol% MnO2: 0.5 mol% Sb2O3, and mix them to form a pressure-sensitive modified mixture.
[0082] Step 2: Mix the pressure-sensitive modified mixture and the fluorescent material (ZE) at a feed ratio of 100 mol% ZE: 1.0 mol% matrix mixture, add anhydrous ethanol ball milling medium, and the ratio of the matrix mixture to anhydrous ethanol is 1 g: 1.5 mL. Ball milling is carried out at a speed of 300 rpm for 8 hours. The ball-to-material ratio during the ball milling process is 10:1 to obtain a ball milling slurry. The ball milling slurry is placed in an oven for drying and sieved to obtain a mixed powder.
[0083] Step 3: Add 8 wt.% polyvinyl alcohol aqueous solution to the mixed powder, where the amount of the polyvinyl alcohol aqueous solution is 2 wt.% of the total amount of the mixed powder, and granulate and mold into a disc-shaped green body.
[0084] Step 4: Place the disc-shaped green body in a muffle furnace, heat it to 600°C at a heating rate of 1°C / min, and bake it for 5 hours to remove the binder. Place the sample after debinding in a muffle furnace, heat it to 1000°C at a heating rate of 3°C / min, and solid-phase sinter it for 2 hours to obtain a luminescent varistor ceramic material, named ZE-MS.
[0085] The structure and performance of the varistor ceramic materials prepared in Examples 2 to 7 and Comparative Example 1 were tested. The varistor ceramic materials prepared in Examples 2 to 7 were named ZE-MSxB, where x is the molar amount of Bi2O3. The results are as follows: Figure 2 The XRD analysis patterns of the piezoresistive ceramic materials prepared in Examples 2 to 7 and Comparative Example 1 of the present invention are shown in FIG. Figure 2 As shown in the figure, all samples are mainly composed of ZnO, and the introduced Bi2O3 forms Bi-rich phase at the grain boundary. 7.72 Mn 0.28 O 12.14 phase, doped Sb2O3 forms Zn7Sb2O 12 and Bi 7.89 Sb 0.11 O 12+x Mutually.
[0086] Figure 3 The scanning electron microscope analysis spectrum of the piezoresistive ceramic materials prepared in Examples 2 to 7 of the present invention and Comparative Example 1 is shown. Figure 3 (a) is comparative example 1, (b) is example 2, (c) is example 3, (d) is example 4, (e) is example 5, (f) is example 6, (g) is example 7, and (h) is average grain size. Figure 3 As shown in Figure 3, it can be seen that with the addition of Bi2O3, the densification degree of the varistor ceramics gradually increases, and the average grain size d estimated by the linear intercept method continuously increases from 2.37μm to 3.86μm.
[0087] Figure 4 This is a graph showing the luminescence performance of the piezoresistive ceramic materials of Examples 3, 5 and 7 of the present invention. Figure 4 (a) is the up-conversion luminescence spectrum, and (b) is the fluorescence decay curve spectrum. Figure 4 As shown, the main peak position of the up-conversion luminescence spectrum of the varistor ceramic material is located at 605nm, and the fluorescence lifetime of the sample increases with the increase of Bi2O3 doping amount, from 215.54ms to 244.54ms.
[0088] Figure 5 is the CIE chromaticity spectrum of the varistor ceramic material of the present invention. Figure 5 As shown, it can be seen that the upconversion luminescence color of the multifunctional varistor ceramic is orange-red.
[0089] The varistor ceramic materials prepared in Examples 2 to 7 and Comparative Example 1 were subjected to surface treatment, electrode coating, and sintering for electrical performance testing. The treatment process was as follows: The solid-phase sintered disc-shaped varistor ceramic sample was polished flat, and conductive silver paste was applied on both sides. After the surface was dried, it was placed in a muffle furnace at 550℃ for 20 minutes to burn the silver electrode and conduct the electrical performance test. The results are shown in Table 1 and Figure 6 、 Figure 7 shown.
[0090] Table 1 Electrical performance data Combined with Table 1 and Figure 6 、 Figure 7 It can be seen that with the increase of Bi2O3 doping amount, the average grain size d gradually increases from 2.37μm at x = 0 to 3.86μm at x = 2.8, and the average grain boundary voltage Vgb increases from 1.28 V to 2.90 V. When the Bi2O3 doping amount is 2.0 mol%, the nonlinear coefficient reaches a peak of 50.18 and the leakage current JL is 0.48μA / mm 2 . , when the acceptor state density Ns is within the doping range, it increases from 1.99×10 16 / m 2 Increased to 3.14×10 16 / m2 , and then decreased to 2.76×10 16 / m 2 Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, they are intended to be included.
Claims
1. A luminescent ZnO-Bi2O3 based varistor ceramic material, characterized in that: The varistor ceramic material is prepared by solid-phase sintering a varistor modifying material and a fluorescent material, wherein the molar ratio of the varistor modifying material to the fluorescent material is 1.8-2.8:100, the varistor modifying material comprises MnO2, Sb2O3 and Bi2O3, and the molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:0.8-2.8; the fluorescent material comprises ZnO and Er2O3, and the doping concentration of Er2O3 in the fluorescent material is 0.2 mol%-0.6 mol%.
2. The luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 1, characterized in that: The molar ratio of MnO2, Sb2O3 and Bi2O3 is 0.5:0.5:1.6~2.
4.
3. The luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 1, characterized in that: The method for preparing the fluorescent material comprises the following steps: According to the composition ratio of the fluorescent material, ZnO and Er2O3 raw materials are weighed and mixed to form a fluorescent mixture; A ball milling medium is added to the fluorescent mixture, ball milling is performed, and uniform powder is obtained after drying. The uniform powder is solid-phase sintered to obtain the fluorescent material.
4. The luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 3, characterized in that: The ball milling time is 6 hours to 10 hours, the rotation speed is 250 rpm to 350 rpm, the solid phase sintering temperature is 1000° C. to 1200° C., and the time is 2 hours to 4 hours.
5. A method for preparing the luminescent ZnO-Bi2O3-based varistor ceramic material according to any one of claims 1 to 4, characterized in that: The following steps are involved: According to the composition ratio of the pressure-sensitive modified material, MnO2, Sb2O3 and Bi2O3 raw materials are weighed and mixed to form a pressure-sensitive modified mixture; The pressure-sensitive modified mixture and the fluorescent material are mixed, a ball milling medium is added, ball milling is performed, and a mixed powder is obtained after drying. A binder is added to the mixed powder, and the mixed powder is granulated and then molded into a green body; The green body is calcined to remove binder, and then solid phase sintered to obtain ZnO-Bi2O3 based varistor ceramic material.
6. The method for preparing the luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 5, characterized in that: The amount of the binder is 1wt.% to 3wt.% of the total amount of the mixed powder. The binder is a polyvinyl alcohol aqueous solution, and the concentration of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 7wt.% to 10wt.%.
7. The method for preparing the luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 5, characterized in that: The temperature for calcining and debinding is 550°C to 650°C, and the holding time is 4h to 6h.
8. The method for preparing the luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 5, characterized in that: The temperature of solid phase sintering is 950℃~1100℃, and the time is 2h~4h.
9. The method for preparing the luminescent ZnO-Bi2O3 based varistor ceramic material according to claim 5, characterized in that: The ball milling time is 6h to 10h, and the rotation speed is 250rpm to 350rpm.