WO2023273901A1 - Non-linear metal oxide rod-shaped resistor and preparation method therefor - Google Patents

Abstract

The present application discloses a non-linear metal oxide rod-shaped resistor and a preparation method therefor. The shape of the non-linear metal oxide rod-shaped resistor is a cylinder, an elliptical column or a polygonal prism, and has a large aspect ratio. The main steps of the preparation method comprise: S100, forming a rod-shaped resistor blank by isostatic pressing and/or dry pressing along the radial direction of the blank; S200, sintering the rod-shaped resistor blank to obtain a semi-finished rod-shaped resistor; and S300, spraying aluminum electrodes on both ends of the semi-finished rod-shaped resistor to obtain a non-linear metal oxide rod-shaped resistor. The preparation method can be used for fabricating a non-linear metal oxide resistor having a large aspect ratio. In comparison with existing round or toroidal resistor sheets, the workload of molding, grinding, aluminum spraying and the like is reduced, the utilization rate of raw materials is enhanced, and raw materials are saved; meanwhile, lightning arrester structures and assembly work are simplified, production efficiency of lightning arresters is improved.

Description

A kind of nonlinear metal oxide rod-shaped resistor and its preparation method

This application claims the priority of the Chinese patent application submitted to the China Patent Office on June 29, 2021 with the application number 202110727714.2 and the title of the invention "A Non-linear Metal Oxide Rod Resistor and Its Preparation Method", the entire content of which Incorporated in this application by reference.

technical field

The invention relates to the technical field of manufacturing nonlinear metal oxide resistors (varistors) for high-voltage arresters, and relates to a method for preparing nonlinear metal oxide rod-shaped resistors. The invention also relates to a non-linear metal oxide rod-shaped resistor for a high-voltage arrester prepared by the preparation method.

Background technique

Nonlinear metal oxide resistors (such as nonlinear zinc oxide resistors) are the core components of metal oxide arresters, and thus are the key components that determine the performance of the arrester. In the current production and manufacture of arresters, it is necessary to combine multiple pie-shaped or ring-shaped resistors, each of which needs to be formed, ground and sprayed with aluminum.

At present, the production of nonlinear metal oxide resistors adopts axial dry pressing and "vertical firing" methods. In the process of dry pressing, pressure is applied in the axial direction. Due to the friction between the green body and the mold, it is difficult to form a high-height-diameter resistor with uniform density; It increases the amount of deformation, and it is difficult to meet the technical requirements; therefore, the ratio of the height to diameter of the produced resistors is generally relatively low, most of which are between 0.2 and 0.8, and the maximum does not exceed 2, all of which are in the shape of discs or rings. Therefore, it is called "resistor sheet".

Contents of the invention

In view of this, the object of the present invention is to provide a method for preparing a nonlinear metal oxide rod resistor. On the basis of adopting the isostatic pressing forming technology, changing the dry pressing forming method and the sintering method, a nonlinear metal oxide rod-shaped resistor with a large aspect ratio is obtained.

Another object of the present invention is to provide a nonlinear metal oxide rod-shaped resistor with a large aspect ratio obtained by the preparation method.

To achieve the above object, the present invention provides the following technical solutions:

A method for preparing a nonlinear metal oxide rod-shaped resistor, comprising the steps of:

S100: pressing into a rod-shaped resistor green body by isostatic pressing and/or by dry pressing along the radial direction of the green body;

S200: Sintering the rod-shaped resistor green body to obtain a rod-shaped resistor semi-finished product;

S300: Spraying aluminum electrodes on both ends of the rod-shaped resistor semi-finished product to obtain a nonlinear metal oxide rod-shaped resistor.

Preferably, in the above-mentioned preparation method, in the step S100, the rod-shaped resistor green body is made by isostatic pressing and/or dry pressing along the radial direction of the green body, specifically:

A rod-shaped resistor blank is pressed separately along the radial direction of the blank by dry pressing;

Or pressed into a rod-shaped resistor blank by isostatic pressing alone;

Or first preform by dry pressing, and then press into a rod-shaped resistor body by isostatic pressing.

Preferably, in the above preparation method, the isostatic pressing method includes dry bag forming and wet bag forming.

Preferably, in the above preparation method, the molding pressure of the dry pressing method is 30-100 MPa, and the molding pressure of the isostatic pressing method is 50-200 MPa.

Preferably, in the above preparation method, in S200, sintering the rod-shaped resistor green body to obtain the rod-shaped resistor semi-finished product is specifically: placing the rod-shaped resistor green body on the supporting surface of the refractory supporting structure For sintering, the refractory supporting structure positions the rod-shaped resistor green body.

Preferably, in the above preparation method, the supporting surface of the refractory supporting structure is a V-shaped groove surface or a U-shaped groove surface or a plane.

Preferably, in the above-mentioned preparation method, in the step S300, before spraying the aluminum electrode on the rod-shaped resistor semi-finished product, an insulating coating is applied on the surrounding surface, and the two ends are ground, and the insulating coating is organic polymer or inorganic glass.

The present invention also provides a nonlinear metal oxide rod-shaped resistor, which is prepared by the preparation method described in any of the above items, and the shape of the section perpendicular to the axial direction of the nonlinear metal oxide rod-shaped resistor is be circular, elliptical or polygonal.

Preferably, in the above-mentioned non-linear metal oxide rod resistor, the circular section diameter or the circumscribed circle diameter of the section of the non-linear metal oxide rod resistor is 20 mm to 80 mm.

Preferably, in the above-mentioned nonlinear metal oxide rod resistor, the aspect ratio of the nonlinear metal oxide rod resistor is not less than 2.

Compared with prior art, the beneficial effect of the present invention is:

The method for preparing a nonlinear metal oxide rod-shaped resistor provided by the present application, the steps include: S100, making a rod-shaped resistor green body by isostatic pressing or dry pressing along the radial direction; S200, The rod-shaped resistor body is sintered to obtain a semi-finished rod-shaped resistor; S300, spraying aluminum electrodes on both ends of the semi-finished rod-shaped resistor to obtain a non-linear metal oxide rod-shaped resistor.

In the preparation method of the nonlinear metal oxide rod-shaped resistor, the green body is formed by isostatic pressing and/or pressed along the radial direction of the green body to form a rod-shaped resistor green body, and finally a non-linear metal oxide body with a relatively large height and diameter is obtained. Compared with the existing axial pressing method, the linear metal oxide rod-shaped resistor can not only form a rod-shaped green body more easily, but also make the density of the pressed rod-shaped resistor green body more uniform. The use of cold isostatic pressing can make the green body uniform in all directions, so it can also be pressed into a nonlinear metal oxide rod-shaped resistor with a large height-to-diameter ratio and uniform density.

In one embodiment of the present invention, compared with the existing "vertical firing" method for sintering rod-shaped resistors, due to gravity and high-temperature load softening, the lower part of the rod-shaped resistors will be greatly deformed. Therefore, the present invention adopts Design a refractory support structure with a V-shaped groove surface or a U-shaped groove surface or a plane, and lay the non-linear metal oxide rod-shaped resistor body flat on the refractory support structure to reduce the deformation caused by sintering.

The method provided by the invention can obtain a nonlinear metal oxide rod-shaped resistor with a large height-to-diameter ratio. Compared with the existing resistor sheet, it greatly reduces the workload of glazing, painting, grinding, and aluminum spraying assembly, and also reduces the The amount of grinding produced during the grinding process can improve the utilization rate of raw materials.

The non-linear metal oxide rod-shaped resistor provided by the present invention can simplify the structure of the arrester due to the large height-to-diameter ratio of the non-linear metal oxide rod-shaped resistor, reduce the workload such as matching and grouping, and improve the production efficiency of the arrester. In some cases, a nonlinear metal oxide rod resistor can be a lightning arrester.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

FIG. 1 is a schematic flow diagram of a method for preparing a nonlinear metal oxide rod-shaped resistor provided by an embodiment of the present invention;

2 is a schematic structural diagram of a nonlinear metal oxide rod resistor provided by an embodiment of the present invention;

3 is a schematic structural diagram of a second nonlinear metal oxide rod resistor provided by an embodiment of the present invention;

4 is a schematic structural diagram of a third nonlinear metal oxide rod resistor provided by an embodiment of the present invention;

5 is a schematic structural diagram of a fourth nonlinear metal oxide rod resistor provided by an embodiment of the present invention;

Fig. 6 is a schematic diagram of the use of the refractory load-bearing structure used in the sintering process in the preparation method of a nonlinear metal oxide rod-shaped resistor provided by the embodiment of the present invention;

7 is a schematic diagram of the use of the refractory load-bearing structure used in the sintering process in another method for preparing a nonlinear metal oxide rod-shaped resistor provided by the embodiment of the present invention;

FIG. 8 is a schematic diagram of the use of the refractory load-bearing structure used in the sintering process in another method for manufacturing a nonlinear metal oxide rod-shaped resistor provided by an embodiment of the present invention.

In the figure, 1 is a rod-shaped resistor blank, 2 is a refractory bearing structure, 21 is a V-shaped groove surface, 22 is a U-shaped groove surface, and 23 is a plane.

detailed description

The invention provides a preparation method of a nonlinear metal oxide rod-shaped resistor, which can obtain a nonlinear metal oxide rod-shaped resistor with a large ratio of height and diameter, and can improve the production efficiency of the arrester when applied to the arrester.

The invention also provides a non-linear metal oxide rod-shaped resistor obtained by the preparation method, which improves the production efficiency of the arrester.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to FIG. 1-FIG. 5. The embodiment of the present invention provides a method for preparing a nonlinear metal oxide rod resistor (hereinafter referred to as rod resistor), which includes the following steps:

Step S100, performing isostatic pressing molding on the green body or dry pressing along the radial direction of the green body to form a rod-shaped resistor green body 1, wherein the green body is formed by spraying and granulating powder, and granulated Materials can be prepared according to methods well known to those skilled in the art;

Step S200, sintering the rod-shaped resistor green body 1 to obtain a semi-finished rod-shaped resistor;

Step S300, spraying aluminum electrodes on both ends of the semi-finished rod-shaped resistor to obtain a rod-shaped resistor. Specifically, the material for electrode spraying is selected according to the different materials of metal oxides used in the green body. For example, if the metal oxide is a mixture of zinc oxide, bismuth oxide and antimony oxide, the material of the electrode spraying can be aluminum.

In the preparation method of the rod-shaped resistor, the green body is pressed and formed along the radial direction of the green body to form a rod-shaped resistor green body 1. sheet, the present application not only makes it easier to form a rod-shaped green body with a relatively large height-to-diameter ratio, but also makes the density of the pressed rod-shaped resistor green body 1 more uniform. The use of isostatic pressing can make the green body uniformly stressed in all directions, so it can also be pressed into a rod-shaped resistor with a relatively large height and diameter and uniform density. Compared with the existing disc-shaped or ring-shaped resistors, due to the large height-to-diameter ratio of the rod-shaped resistors, compared with the existing processes of forming, grinding and spraying aluminum for each resistor, it greatly reduces the The workload of glazing, painting, grinding, and aluminum spraying improves production efficiency and saves manufacturing and material costs.

Further, in this embodiment, in step S100, the rod-shaped resistor green body is pressed by the isostatic pressing method and/or the dry pressing method along the radial direction of the green body. Specifically, the dry pressing method can be used alone along the radial direction The green body can be pressed and formed; the green body can also be pressed and formed by isostatic pressing alone; it can also be preformed by dry pressing and then finally pressed by isostatic pressing. Among them, the isostatic pressing method can make the green body uniformly stressed in all directions, so the density will be more uniform when pressing the rod-shaped resistor with a large ratio of height to diameter.

As an optimization, in this embodiment, the isostatic pressing method includes a dry bag forming method and a wet bag forming method. The dry bag forming method facilitates automatic production.

As an optimization, in this embodiment, the forming pressure of the dry pressing forming method is 30MPa-100MPa, and the forming pressure of the isostatic pressing forming method is 50MPa-200MPa. The appropriate forming pressure is selected according to actual needs, and is not limited to this embodiment. Pressure range listed.

As shown in Figures 6-8, further, in this embodiment, the sintering of the rod-shaped resistor green body 1 in step S200 is specifically: placing the rod-shaped resistor green body 1 flat on the refractory supporting structure 2 Sintering is carried out on the supporting surface, and the rod-shaped resistor green body 1 is positioned on the supporting surface. Specifically, the axis of the rod-shaped resistor blank 1 is placed horizontally, and the rod-shaped resistor blank 1 is placed on the supporting surface, and the supporting surface is positioned in contact with the surface of the rod-shaped resistor blank 1 to prevent the rod-shaped resistor from Green body 1 rolls or slides. In the prior art, the resistor green body is sintered with the axis vertically placed. Due to the gravity, the lower part of the resistor green body will bear a large pressure and cause deformation. The larger the aspect ratio, the greater the deformation. However, the sintering of the rod-shaped resistor green body 1 in this embodiment is carried out by laying flat on the refractory supporting structure 2 to reduce the deformation caused by sintering.

As an optimization, the supporting surface of the refractory supporting structure 2 is a V-shaped groove surface 21 or a U-shaped groove surface 22 or a plane 23 . The V-shaped groove surface 21 , the U-shaped groove surface 22 and the plane 23 are selected according to the cross-sectional shape of the rod-shaped resistor blank 1 . For example, if the cross-sectional shape of the rod-shaped resistor body 1 is circular, a refractory supporting structure 2 with a V-shaped groove surface or a U-shaped groove surface can be selected, and both the V-shaped groove surface 21 and the U-shaped groove surface 22 can be positioned A rod-shaped resistance body 1 with a circular cross-section; if the cross-sectional shape of the rod-shaped resistance body 1 is polygonal, a V-shaped groove surface 21 or a flat refractory supporting structure 2 can be selected, and the angle of the V-shaped groove surface 21 is the same as The angles of the polygonal cross-sections are matched to play a positioning role. The surface of the rod-shaped resistor body 1 with a polygonal cross-section can be placed flat on the plane 23, and it is not easy to roll over. As long as an appropriate supporting surface can be selected according to different cross-sectional shapes of the rod-shaped resistor blank 1 , it is not limited to the shapes listed in this embodiment.

Further, in this embodiment, in step S300, before spraying aluminum electrodes on both ends of the rod-shaped resistor semi-finished product, an insulating coating is applied on the surrounding surface, and the two ends are ground, and the insulating coating is organic polymer or Inorganic glass, specifically, the insulating coating can be epoxy resin or lead-free or lead-containing low-temperature glass. Both ends are ground to make the size and shape of the semi-finished rod resistance more accurate. Compared with the existing grinding process for each ring-shaped or round cake-shaped resistor, this application only needs to grind the two ends of a rod-shaped resistor, which greatly reduces the grinding process during the grinding process Quantity, improve the utilization rate of raw materials, save raw materials, reduce costs, and improve the preparation efficiency.

As shown in Figure 2-Figure 5, based on the preparation method of the rod-shaped resistor described in any of the above embodiments, the embodiment of the present invention also provides a rod-shaped resistor prepared by this preparation method, the rod-shaped resistor is perpendicular to the axis The shape of the cross-section is circular, polygonal or elliptical.

Since the rod-shaped resistors are obtained by the preparation method in this application, compared with the existing disc-shaped or ring-shaped resistors, since the height-diameter ratio of the rod-shaped resistors is relatively large, it is molded with each existing resistor , grinding and aluminum spraying process, this application greatly reduces the glazing, painting, grinding, aluminum spraying assembly workload, reduces the amount of grinding produced in the grinding process, improves the utilization rate of raw materials, and saves raw materials The production efficiency of the arrester is improved.

Further, in this embodiment, the diameter of the circumscribed circle of the cross-section perpendicular to the axial direction of the rod-shaped resistor is 20 mm to 80 mm. For a rod-shaped resistor with a circular cross-section, the diameter of the circumscribed circle is the diameter of the circular cross-section. For polygonal For rod-shaped resistors with cross-section, the diameter of the polygonal cross-section is the circumcircle diameter, and for the ellipse, the circumcircle diameter is the major axis diameter.

Further, in this embodiment, the aspect ratio of the rod-shaped resistor is not less than 2, wherein the aspect ratio refers to the ratio of the height of the rod-shaped resistor to the diameter of the circumscribed circle of the section.

The preparation of rod-shaped resistors will be illustrated below by taking regular quadrangular prism resistors as an example.

Example 1

Use different molding methods and molding pressures to press rod-shaped resistors with different aspect ratios.

test one

Compress 30 regular quadrangular prism resistors with a bottom side length of 30mm and a height of 60mm by dry pressing, and the molding pressure is 50MPa;

Test two

Press 30 square prism resistors with a bottom side length of 30mm and a height of 90mm by dry pressing, and the molding pressure is 80MPa;

Trial Three

Press 30 square prism resistors with a bottom side length of 30mm and a height of 120mm by dry pressing, and the molding pressure is 100MPa;

test four

Press dry bag forming method to press 30 square prism resistors whose base length is 30mm and height is 60mm, and the molding pressure is 50MPa;

Test five

Press dry bag forming method to press 30 square prism resistors whose base length is 30mm and height is 90mm, and the molding pressure is 80MPa;

Test six

Press dry bag forming method to press 30 square prism resistors whose base length is 30mm and height is 120mm, and the molding pressure is 100MPa;

Test seven

Preform by dry pressing method firstly, then use wet bag forming method to press 30 regular square prism resistors whose base length is 30mm and height is 60mm, and the molding pressure is 50MPa;

Test eight

Preform by dry pressing method firstly, then use wet bag forming method to press 30 regular square prism resistors with bottom side length 30mm and height 90mm, molding pressure is 80MPa;

test nine

Preformed by dry press molding method, and then pressed 30 regular quadrangular prism resistors with bottom side length of 30mm and height of 120mm by wet bag molding method, and the molding pressure is 100MPa.

Result analysis:

Density tests were carried out on the bodies of the above nine tests, and the test results are shown in Table 1.

Table 1 Rod resistance density of different molding methods and molding pressure

It can be seen from Table 1 that with the increase of the molding pressure, the density of the green body pressed by the dry pressing method tends to be stable after increasing to 80MPa, and the density increases to a maximum of 3.23g/cm ³ , while the dry bag molding method increases with The density increases continuously with the increase of molding pressure, the maximum density is 3.40g/cm ³ , the density of the wet bag molding method also increases with the increase of the molding pressure after the preforming of the dry pressing molding method, and the maximum density increases to 3.41g/cm ³ . The change trend of sintered density is basically the same as that of green body. The maximum density of the rod-shaped resistors pressed by the dry pressing method is 5.65g/cm ³ , and the density of the rod-shaped resistors pressed by the two isostatic pressing methods is about 5.71g/cm ³ . It can be seen that under the same molding pressure, the rod-shaped resistors pressed by the isostatic pressing method have a higher density than the rod-shaped resistors pressed by the dry pressing method.

Example 2

Rod resistors are sintered by different sintering methods.

test one

Sinter 30 regular quadrangular prism resistors with a side length of 30 mm and a length of 120 mm in a vertical manner.

Test two

30 regular quadrangular prism resistors with a base length of 30 mm and a length of 120 mm are placed on the refractory supporting structure 2 of the V-shaped groove surface 21 with an included angle of 90° for sintering.

Trial Three

It is 30mm that the side length of 30 bases, the regular quadrangular prism resistance of long 120mm are placed flatly on the refractory support structure 2 that support surface is plane 23 and carry out sintering.

Result analysis:

For the above three sets of rod-shaped resistors, the side lengths and deformations of the two bottom surfaces were tested respectively, and the specific data are shown in Table 2.

Table 2 Deformation of rod resistance in different sintering methods

test	one	two	three
End face 1(mm)	23.6	23.7	23.6
End face 2(mm)	24.8	23.6	23.6
Deformation (mm)	1.2	0.1	0

It can be seen that the resistance deformation of the square prism sintered in the horizontal way is much smaller than that of the vertical sintering method.

Example 3

DC reference voltage of rod resistors under different molding methods and molding pressures.

test one

Compress 30 regular quadrangular prism resistors with a bottom side length of 30mm and a height of 120mm by dry pressing, and the molding pressure is 50MPa;

Test two

Press 30 regular quadrangular prism resistors with a bottom side length of 30mm and a height of 120mm by dry pressing, and the molding pressure is 80MPa;

Trial three

Press 30 square prism resistors with a bottom side length of 30mm and a height of 120mm by dry pressing, and the molding pressure is 100MPa;

test four

Press dry bag forming method to press 30 regular quadrangular prism resistors whose base length is 30mm and height is 120mm, and the molding pressure is 50MPa;

Test five

Press dry bag forming method to press 30 square prism resistors whose base length is 30mm and height is 120mm, and the molding pressure is 80MPa;

Test six

Squeeze 30 regular quadrangular prism resistors whose bottom surface side length is 30mm and height is 120mm with the dry bag forming method, and the molding pressure is 100MPa;

Test seven

Preform by dry pressing method first, then use isostatic pressing method to press 30 regular rectangular prism resistors with bottom surface side length 30mm and height 120mm, molding pressure is 50MPa;

Test eight

Preformed by dry pressing method, and then pressed 30 square prism resistors with bottom side length of 30mm and height of 120mm by isostatic pressing method, and the molding pressure is 80MPa;

test nine

First preformed by dry pressing method, and then pressed 30 regular quadrangular prism resistors with bottom side length of 30 mm and height of 120 mm by isostatic pressing method, and the forming pressure was 100 MPa.

Result analysis:

Sinter the above nine groups of rod-shaped resistors and test the DC reference voltage, the results are shown in Table 3.

Table 3 DC reference voltage of rod resistors in different molding methods

It can be seen from Table 3 that the DC reference voltage of the rod resistor after dry pressing and isostatic pressing is about 26kV, so it is feasible to produce rod resistors by dry pressing and isostatic pressing.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A method for preparing a nonlinear metal oxide rod-shaped resistor, comprising the steps of:

   S100: pressing into a rod-shaped resistor green body by isostatic pressing and/or by dry pressing along the radial direction of the green body;

   S200: Sintering the rod-shaped resistor green body to obtain a rod-shaped resistor semi-finished product;

   S300: Spraying aluminum electrodes on both ends of the rod-shaped resistor semi-finished product to obtain a nonlinear metal oxide rod-shaped resistor.
2. The preparation method according to claim 1, characterized in that, in the step S100, the rod-shaped resistor green body is pressed into a rod-shaped resistor body by isostatic pressing and/or dry pressing along the radial direction of the green body, specifically:

   A rod-shaped resistor blank is pressed separately along the radial direction of the blank by dry pressing;

   Or pressed into a rod-shaped resistor blank by isostatic pressing alone;

   Or first preform by dry pressing, and then press into a rod-shaped resistor body by isostatic pressing.
3. The preparation method according to claim 1, characterized in that, the isostatic pressing method comprises dry bag forming and wet bag forming.
4. The preparation method according to claim 3, characterized in that, the forming pressure of the dry pressing forming method is 30-100 MPa, and the forming pressure of the isostatic pressing forming method is 50-200 MPa.
5. The preparation method according to claim 1, characterized in that, in the S200, sintering the rod-shaped resistor blank to obtain the rod-shaped resistor semi-finished product is specifically: placing the rod-shaped resistor blank on the side of the refractory supporting structure Sintering is performed on the supporting surface, and the refractory supporting structure positions the rod-shaped resistor body.
6. The preparation method according to claim 5, characterized in that, the supporting surface of the refractory supporting structure is a V-shaped groove surface or a U-shaped groove surface or a plane.
7. The preparation method according to claim 1, characterized in that, in the step S300, before spraying aluminum electrodes on the rod-shaped resistance semi-finished product, the peripheral surface is coated with an insulating coating, and the two ends are ground, and the The insulating coating is organic polymer or inorganic glass.
8. A nonlinear metal oxide rod-shaped resistor, characterized in that it is prepared by the preparation method described in claims 1-7, and the shape of the section perpendicular to the axial direction of the nonlinear metal oxide rod-shaped resistor is be circular, elliptical or polygonal.
9. The nonlinear metal oxide rod-shaped resistor according to claim 8, characterized in that, the circular section diameter or the circumscribed circle diameter of the section of the nonlinear metal oxide rod-shaped resistor is 20 mm to 80 mm.
10. The nonlinear metal oxide rod resistor according to claims 8 and 9, characterized in that the aspect ratio of the nonlinear metal oxide rod resistor is not less than 2.

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