Inorganic ceramic insulating material surface charge regulation and control method based on temperature gradient
By doping functional ions to regulate the micromorphology of ceramic insulating materials and optimize the carrier migration path, the problem of surface charge accumulation under temperature gradient is solved, and the uniformity of electric field distribution and the improvement of insulation performance are achieved.
Patent Information
- Application Number
- CN202510891016.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-09-16
AI Technical Summary
Existing technologies lack methods for regulating charge accumulation on the surface of ceramic insulating materials under temperature gradient conditions, resulting in electric field distortion and flashover risks, and a lack of in-depth understanding of how the microstructure affects the carrier migration path and method under temperature gradient.
By doping functional ions such as Cr3+, Ce3+, Gd3+, and Nd3+ to regulate the micromorphology of inorganic ceramic insulating materials, combined with scanning electron microscopy and X-ray diffraction technology, the carrier migration path and migration ability are analyzed, the surface charge accumulation characteristics are optimized, and the optimal doping system is selected to achieve uniform electric field distribution.
It effectively suppresses surface charge accumulation under temperature gradient, improves the insulation performance of post insulators, reduces flashover risks, and increases the safety margin of gas-insulated power equipment.
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Figure CN120647425A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of ceramic materials, and in particular to a method for regulating the surface charge of inorganic ceramic insulating materials based on a temperature gradient. Background Art
[0002] Gas-insulated power equipment (GIPE) is widely used in modern power systems due to its high reliability, miniaturization, and environmental adaptability. As a key insulating component in GIPE, post insulators fulfill the crucial function of supporting high-voltage conductors and isolating conductors at different potentials. Their insulation performance is directly related to the safe and stable operation of the entire equipment.
[0003] During the actual operation of gas-insulated power equipment, post insulators are in a complex multi-physical field coupling environment for a long time. On the one hand, their surfaces are subjected to extremely high operating electric field strength; on the other hand, due to factors such as conductor heating and ambient temperature changes, there is often a significant temperature gradient along the radial direction of the insulator. This high field strength-large temperature difference combined stress constitutes a special operating condition for post insulators.
[0004] Existing research shows that under special working conditions such as temperature gradient, the surface charge accumulation characteristics at the interface between SF6 and solid insulating materials of post insulators have a decisive influence on the insulation performance. The uneven surface charge distribution will cause serious distortion of the local electric field, significantly reducing the surface flashover voltage of the insulator, becoming one of the main factors inducing surface flashover failures inside gas-insulated power equipment, threatening the safe operation of the power system.
[0005] At present, the research on the surface charge problem of ceramic insulating materials mainly attempts to change the bulk conductivity, trap characteristics, etc. of the material by doping different elements or using composite materials, in order to affect the migration and dissipation of the charge. However, when dealing with surface charge regulation under temperature gradient conditions, most existing technical solutions focus on the charge behavior under room temperature or single stress (such as only electric field), and lack understanding of the special mechanism of charge migration, accumulation and dissipation under the key operating condition of temperature gradient. Although existing modification methods may be effective, they often lack an in-depth understanding of how the microstructure (such as grain size, grain boundary characteristics, phase composition, element distribution) affects the path and method of carrier (electron, ion) migration from the bulk phase of the material to the surface under temperature gradient. There is a lack of systematic research on how the micromorphology (including cross-sectional morphology, element distribution, phase composition) affects the carrier concentration and migration ability, and thus regulates the surface charge accumulation characteristics under temperature gradient. Summary of the Invention
[0006] Based on the above problems, the present invention provides a method for regulating the surface charge of inorganic ceramic insulating materials based on temperature gradient. By regulating the micromorphology of inorganic ceramic insulating materials, especially using doping with different functional ions as an effective means to achieve controllable changes in the micromorphology, in-depth research is conducted on how these microstructural characteristics affect the migration path and migration ability of carriers from the material body to the surface under temperature gradient conditions, thereby revealing the intrinsic regulation mechanism between the micromorphology, carrier migration behavior and surface charge accumulation characteristics. The ultimate goal is to optimize the inorganic ceramic insulating material formula system with the least surface charge accumulation and the most uniform electric field distribution under temperature gradient conditions, providing a key material solution for the manufacture of high-performance and high-reliability gas-insulated power equipment post insulators, effectively solving the surface flashover problem caused by surface charge accumulation, and improving the safety margin of gas-insulated power equipment operation.
[0007] A method for regulating the surface charge of an inorganic ceramic insulating material based on a temperature gradient comprises regulating the micromorphology of the inorganic ceramic insulating material by doping functional ions; characterizing and analyzing the micromorphology to obtain characterization results; and analyzing, based on the characterization results, the regulation mechanism of the surface charge characteristics of the inorganic ceramic insulating material under the temperature gradient, optimizing the migration path and migration ability of carriers from the material body to the surface, and regulating the surface charge accumulation characteristics to obtain a target doping system as the surface charge regulation result of the inorganic ceramic insulating material.
[0008] Furthermore, the functional ions include Cr 3+ 、Ce 3+ 、Gd 3+ and Nd 3+ At least one of .
[0009] Furthermore, the temperature gradient is 393K / 328K.
[0010] Furthermore, the characterization analysis includes cross-sectional micromorphology characterization, element distribution micromorphology characterization, and phase composition micromorphology characterization.
[0011] Furthermore, the cross-sectional micromorphology characterization is performed using a scanning electron microscope to obtain the cross-sectional micromorphology and surface element composition and distribution results of the inorganic ceramic insulating material.
[0012] Furthermore, the element distribution micromorphology is characterized by using X-ray energy spectrum analysis to analyze the element composition and distribution pattern of the material.
[0013] Furthermore, the phase composition micromorphology is characterized by X-ray diffraction testing to analyze the crystal structure and phase composition of the material.
[0014] Furthermore, the surface charge regulation mechanism is that the different micromorphologies and phase compositions of inorganic ceramic insulating materials affect their carrier concentration and ability to migrate from the bulk to the surface. The effect of the grain boundaries of the material on carrier migration can be determined through the micromorphology characterization results, thereby optimizing the surface charge accumulation characteristics of inorganic ceramic insulating materials under temperature gradients.
[0015] The advantages of the present invention are:
[0016] The present invention provides a method for regulating the surface charge of an inorganic ceramic insulating material based on a temperature gradient. The method comprises preparing an inorganic ceramic insulating material doped with different functional ions to achieve a change in the micromorphology, performing different characterizations on the micromorphology of the ceramic insulating material, observing the SEM, XRD, and EDS test results of the inorganic ceramic insulating material doped with different functional ions, comparing the surface charge characteristics of each formulation system, and analyzing the regulation mechanism of the surface charge characteristics of the inorganic ceramic insulating material under temperature gradient conditions. The method thus controls the mode and path of carrier migration from the bulk to the surface, thereby affecting the surface charge accumulation characteristics of the ceramic insulating material under temperature gradient conditions, and optimizing the formulation system of the inorganic ceramic insulating material with the least surface charge accumulation under temperature gradient conditions, thereby achieving the purpose of regulating the surface charge of the ceramic material for use in post insulators in gas-insulated power equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a comparison chart of the surface charge density of ceramic insulating materials doped with different functional ions under temperature gradient.
[0018] Figure 2 1 is the SEM-EDS spectrum of the ceramic insulating material doped with different functional ions in Example 1. DETAILED DESCRIPTION
[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0020] It should be noted that the various installation methods and technical terms mentioned in the present invention are technical terms that have long been clearly known in the relevant technical field and therefore will not be further explained. In addition, the same reference numerals are used for the same components, but this does not affect nor constitute an accurate understanding of the technical solution by those skilled in the art.
[0021] Example 1
[0022] This embodiment provides a method for controlling the surface charge of an inorganic ceramic insulating material based on a temperature gradient, wherein different functional ions are doped (the different functional ions doped in this embodiment are Cr 3+ 、Ce 3+ 、Gd 3+ 、Nd 3+ ) were used to prepare different alumina ceramic insulating materials, and the micromorphology, element distribution and phase composition of different alumina ceramic insulating materials were characterized and analyzed by SEM-EDS test and XRD test. The temperature gradient was set to 393K / 328K (the temperature gradient was set based on the actual operating conditions of the support insulators in the gas-insulated power equipment). The modulation effect of the carrier concentration and the difficulty of migration from the body to the surface on the surface charge characteristics of the alumina ceramic insulating material under the temperature gradient condition was analyzed, and then the surface charge regulation of the inorganic ceramic insulating material under the temperature gradient condition was realized to obtain the target doping system that can regulate the surface charge accumulation characteristics (the optimal doping system is the inorganic ceramic insulating material formula system for preparing doped functional ions with the least surface charge accumulation and the most uniform electric field distribution under the temperature gradient condition, which is selected according to the characterization results) as the surface charge regulation result of the inorganic ceramic insulating material, such as Figure 1 shown.
[0023] Among them, the modulation effect of the carrier concentration and the difficulty of migration from the body to the surface on the surface charge characteristics of alumina ceramic insulating materials under the temperature gradient working condition is analyzed as follows: under the temperature gradient of 393K / 328K, the Cr-doped 3+ Alumina ceramics with high temperature will activate impurities, introduce greater electronic conductivity, increase carrier concentration, and accelerate the migration of charges from the body to the surface, resulting in increased surface charge accumulation; while Ce-doped 3+ The impurity phase CeAl2O4 introduced into the ceramic material has poor temperature stability and can introduce oxygen vacancies to activate, causing a sudden increase in carrier concentration and a significant increase in surface charge density; Gd doping 3+ The impurity phase GdAl3O6 introduced into the ceramic material has good temperature stability, hinders the migration of carriers from the body to the surface, and significantly reduces the surface charge accumulation; doping Nd 3+ The ceramic material forms a new phase Nd 0.85 Al 11.95 O 18.5 It is highly consistent with the original grain boundary phase distribution area, the difficulty of carrier migration from the body to the surface remains unchanged, and the surface charge accumulation does not change much compared with the alumina ceramic insulating material.
[0024] Therefore, it is concluded that the use of Gd 3+The doped inorganic ceramic material is the optimal doping system (target doping system) for regulating the surface charge accumulation characteristics, which can achieve optimal regulation of the surface charge and is used to prepare post insulators in gas-insulated power equipment to improve their surface charge characteristics under temperature gradient conditions. It is the regulation result obtained by the surface charge regulation method of inorganic ceramic insulating materials based on temperature gradient in this embodiment.
[0025] The characterization analysis includes cross-sectional micromorphology characterization, element distribution micromorphology characterization, and phase composition micromorphology characterization, as follows:
[0026] ① Characterization of cross-sectional micromorphology: A scanning electron microscope equipped with an energy spectrometer (Scanning Electron Microscope-Energy Dispersive Spectrometer, SEM-EDS) is used to obtain the micromorphology and analyze the distribution characteristics of the surface elements. The measurement surface is the cross-sectional structure of the sample, and the test surface is gold-sprayed before testing to enhance its conductivity. The scanning electron microscope uses a high-energy electron beam to interact with the atoms on the sample surface, generating signals such as secondary electrons, backscattered electrons, and characteristic X-rays. By detecting and analyzing these signals, the micromorphology of the surface of the inorganic ceramic insulating material sample can be obtained. The results are as follows: Figure 2 As shown, from Figure 2 The alumina ceramics without functional ion doping can be obtained with large and uniform grain size and no obvious intergranular gaps; 3+ The grain size of alumina ceramics is significantly reduced; Ce doping 3+ The grain size of alumina ceramics is smaller than that of Cr 3+ Compared with undoped alumina, the 3+ The grain size of alumina ceramics is greatly reduced compared with undoped alumina ceramics, and the distribution is more uniform; 3+ The alumina ceramic grains are small in size but unevenly distributed, and there are large gaps between the grains.
[0027] ② Characterization of element distribution and micromorphology: Energy dispersive X-ray spectrometer (EDS) analyzes the elemental composition and distribution of materials through X-ray energy spectrum analysis. The basic principle of EDS is that when the electron beam is incident on the sample, it interacts with the sample atoms and stimulates the atoms' own X-rays. Atoms of different elements have different energy level structures and thus exhibit different X-ray energies. By detecting the energy and intensity of characteristic X-rays, the type and content of elements present in the sample can be determined. At the same time, the analysis software provided by the energy spectrometer is used to process the signal, automatically identify the characteristic peaks and match the corresponding elements and their contents. The overall analysis of the micromorphology of inorganic ceramic insulating materials is achieved by combining the element distribution with the SEM image. The element distribution results show that Cr is relatively evenly distributed in alumina, similar to the distribution characteristics of Al and O; Ce, Gd, and Nd elements are mainly distributed in the grain boundary area.
[0028] ③ Characterization of phase composition and micromorphology: X-ray diffraction (XRD) testing is based on the Bragg law and the interaction between X-rays and crystal materials to analyze parameters such as the crystal structure and phase composition of the material; the diffraction pattern data obtained by the X-ray diffractometer test is imported into the Jade software for analysis; after removing the large background noise, the diffraction pattern obtained by the side hand is compared with the standard card to confirm the phase composition of the sample, and the result is Cr 3+ Doped alumina appears a solid solution of Cr2O3 and Al2O3 (Al 1-x Cr x)2 O3; Ce 3+ Doping alumina produces a new impurity phase CeAl2O4, which is distributed at the grain boundaries; Gd 3+ Doping alumina produces a new grain boundary phase GdAl3O6; Nd 3+ Doping alumina produces a new phase Nd 0.85 Al 11.95 O 18.5 , which is highly consistent with the original grain boundary phase distribution area.
[0029] Therefore, the results of this embodiment can be concluded that Gd-doped 3+ The inorganic ceramic insulating material effectively hinders the migration of carriers from the body to the surface by introducing a new grain boundary phase, inhibits the accumulation of surface charge, and obtains excellent surface charge performance under temperature gradient conditions.
[0030] The working mechanism of the method for regulating the surface charge of inorganic ceramic insulating materials under temperature gradient by micromorphology provided in this embodiment is as follows:
[0031] The different micromorphologies and phase compositions of inorganic ceramic insulating materials affect their carrier concentration and ability to migrate from the bulk to the surface, thereby optimizing the surface charge accumulation characteristics of inorganic ceramic insulating materials under temperature gradients. By doping with different functional ions, the carrier concentration in inorganic ceramic insulating materials is altered. The functional ion doping produces new grain boundary phases, which reduce the formation of ceramic grain solid solutions and oxygen vacancies, significantly reducing the carrier concentration. Furthermore, the larger ionic radius hinders the migration of carriers along the grain boundary phases, making it difficult for carriers to migrate to the surface, thus inhibiting the migration of carriers from the bulk to the surface. These two factors work together to reduce surface charge accumulation. Under temperature gradients, the surface charge density is primarily affected by the concentration of impurity carriers within the inorganic ceramic insulating material and the ease of their migration. As temperature rises, the temperature-stable grain boundary phases hinder the migration of carriers from the bulk to the surface, and the spatial distribution of surface charge is unaffected by temperature and remains uniform.
[0032] The present invention provides a method for regulating the surface charge of inorganic ceramic insulating materials based on temperature gradient. Through this micromorphology regulation, effective regulation of the surface charge characteristics of ceramic insulating materials under temperature gradient conditions is achieved, thereby solving the problems of electric field distortion and flashover risk caused by uneven surface charge distribution of post insulators.
[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention may be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all variations that fall within the meaning and range of equivalents of the claims be embraced within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.
[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention shall be included in the scope of protection of the technical solution of the present invention.
Claims
1. A method for controlling the surface charge of an inorganic ceramic insulating material based on a temperature gradient, characterized in that: Including regulating the micromorphology of inorganic ceramic insulating materials by doping functional ions; Characterize and analyze the microscopic morphology to obtain characterization results; Based on the characterization results, the surface charge characteristics of inorganic ceramic insulating materials under temperature gradient are analyzed, and the migration path and migration ability of carriers from the material body to the surface are optimized to regulate the surface charge accumulation characteristics and obtain the target doping system as the surface charge regulation result of inorganic ceramic insulating materials.
2. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 1, characterized in that: The functional ions include Cr 3+ 、Ce 3+ 、Gd 3+ and Nd 3+ At least one of .
3. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 2, characterized in that: The doping amount of the functional ions is 1% to 4%.
4. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 1, characterized in that: The temperature gradient is 393K / 328K.
5. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 1, characterized in that: The characterization analysis includes cross-sectional micromorphology characterization, element distribution micromorphology characterization, and phase composition micromorphology characterization.
6. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 5, characterized in that: The cross-sectional micromorphology characterization is conducted using a scanning electron microscope to obtain the cross-sectional micromorphology and surface element composition and distribution results of the inorganic ceramic insulating material.
7. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 5, characterized in that: The element distribution micromorphology characterization uses X-ray energy spectrum analysis to analyze the element composition and distribution pattern of the material.
8. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 5, characterized in that: The phase composition micromorphology is characterized by X-ray diffraction testing to analyze the crystal structure and phase composition of the material.
9. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 1, characterized in that: The analysis of the surface charge characteristics of the inorganic ceramic insulating material under the temperature gradient includes analyzing the charge density and spatial distribution.
10. The method for controlling surface charge of inorganic ceramic insulating materials based on temperature gradient according to claim 9, characterized in that: The target doping system is a doping system used to prepare an inorganic ceramic insulating material with minimal surface charge accumulation and uniform electric field distribution.