JPS61204902A - Manufacture of voltage non-linear resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voltage nonlinear resistor used in a zinc oxide lightning arrester.

[Conventional technology]

Conventionally, zinc oxide voltage nonlinear resistors used in lightning arresters, etc., have the following characteristics: excellent voltage nonlinearity, large surge absorption capacity, and resistance to deterioration caused by voltage application.
There is a growing demand for long life.

Among these, external flash shorting at the side surface of the element limits the surge absorption ability. In many cases, the trigger is a micro discharge at the end face of the element, and for this reason, a high resistance layer (7 ) to prevent this. Conventionally, there are two main methods known for forming a high resistance layer. The powder is mixed with an organic binder, coated on a molded body, and sintered at the same time to form a voltage nonlinear resistor C as a high resistance layer.
(c). Other methods.

- A paste-like paste of low-melting glass frit with an organic binder is applied to the side surface of the sintered voltage nonlinear resistor (1).
Coating 1-5 This is heated and vitrified to form a high resistance layer.

As shown schematically, lead oxide particles (su) and spinel particles (
M), BiJOJ is added to the grain boundary layer to fill those voids.
(Bismuth e) (t) exists. In recent years, it has become clear that the R1.203 crystal phase present in this grain boundary layer has a strong influence on the non-alignment properties and life characteristics.

In other words, shou fi? One example of i-characteristics is the difference in the crystal phase of bismuth oxide, which is the current when a constant pressure is applied.

This greatly affects the so-called τ rate of leakage current.

Figure 3 shows seven examples of life characteristics, namely, the imposed rate gθ%1 ambient temperature 1f/? It shows the change over time in the leakage current ratio (normalized by the initial current) at θ°C.

Curve A in the figure contains 3% body-centered cubic bismuth oxide.

Curve B contains the same 7%, Curve C contains the same bo%, and the curves contain the same <9.3'%.

On the other hand, the key to forming body-centered cubic bismuth oxide into a voltage nonlinear resistor depends on the composition of additives, the firing conditions, etc. If the company stipulates a manufacturing method with a reduced composition.

Strictly speaking, the one-ton ratio of the body-centered cubic crystal is individually determined: (9
The effect is 5) The mouth and the mouth are shown C(・ru(%, chin Show 9
to t//j/l, No. 3) Q or 2. l' What is the relationship between the reheating temperature and the conversion rate to body-centered cubic bismuth oxide as shown in the figure? Therefore, the third [A, leakage from Figure 7: 1m, the reheating temperature with a small ratio (roo・-mi 06' is limited to around 06').

[The point of view that the invention seeks to solve 1] Conventionally, the formation of +I + l + high abrasive surface a and the adjustment of the conversion rate of bismuth oxide to body-centered cubic crystals have been performed in separate steps. However, this poses several problems in terms of increased man-hours and yield.

The object of the present invention is to reduce the complexity of the steps as described above, reduce the number of scraping steps, and improve the yield.

[Means for solving problems]

1. However, in this invention, a non-conducting resistor element is manufactured by forming a raw material containing zinc oxide as the main component and at least bismuth oxide, and a high-resistance layer is sintered on the side surface of this element. Later, in a method for manufacturing a peeping pressure non-hundred wire resistor which essentially consists of converting a predetermined amount of bismuth oxide into a body-centered cubic crystal, the conversion temperature at which a predetermined amount of bismuth oxide is converted into a body-centered cubic crystal is determined. A glass frit having a sintering temperature range in the same temperature range as the voltage nonlinear resistor and an expansion coefficient matching within ±10% with the expansion coefficient of the voltage nonlinear resistor is applied to the side surface of the element, and the side high resistance layer is formed by heating. The present invention relates to a method of manufacturing a voltage nonlinear resistor in which the formation of bismuth oxide and the conversion of bismuth oxide to a body-centered cubic crystal are performed simultaneously.

[For production]

This invention utilizes a glass lift in the same temperature range as that required to obtain the conversion rate of bismuth oxide to body-centered cubic crystals necessary to stabilize the life of a voltage nonlinear resistor. For the H structure of a non-+Tjfihl resistor, if the formation of a side high resistance layer and the control of the crystal phase of bismuth oxide, that is, the individualization of the rolling stone into a body-centered cubic crystal, are performed in a single heating process. It is something to do.

The glass frit used in this invention is a low melting acid -8iO
a-BaO, y-based, etc. These materials are suitable for use not only in terms of temperature change, but also because their expansion coefficients are close to (within ±lθ%) the expansion coefficients of sintered bodies of electric, non-IM, wire abrasives. If the expansion coefficient exceeds 70%, it is not preferable because adhesion of glass becomes difficult or the element becomes deformed.

〔Example〕

The present invention will be explained below based on Examples.

Example / Zinc oxide is the main component, and 0.5 mol% of chromium oxide, nickel oxide, cobalt oxide, manganese oxide, silicon oxide, bismuth oxide, and antimony oxide of 0 mol% are added as additives. The ingredients are thoroughly mixed, granulated, and then molded. /, Baked at 200℃, YuOX, 2. l
The element 1a, which has a size of about tt, is shown in the figure (,
2) For the voltage nonlinear resistor body, select a glass frit whose linear expansion coefficient is within CEF 05 of the linear expansion coefficient of the fired body (approximately AOX10'//℃) and whose working temperature range is around &j O'C. This powder is mixed and coated with a solvent containing a binder such as nitrocellulose, and this is heated to form a glass layer, that is, a high resistance layer on the side surface of the low melting point glass frit shown in 1B (3) in the figure, and to convert bismuth oxide crystals. was done at the same time. It is important to set the heating time to about 1 to 1 hour and to carry out the heating under conditions where sufficient oxygen can be supplied.

It has become clear that it is a mixed crystal of bismuth oxide in the tetragonal crystal form and bismuth oxide in the r-form (body-centered cubic crystal form). The fine structure of the obtained voltage nonlinear resistor is shown in Fig. 11).

We actually conducted a lifespan test.

A stable change in current over time was shown as shown by curve AK in Figure 3. On the other hand, to see the effect of the high resistance layer on the side.

eX10μs, /l! 7 (When a surge current of 7 KA was applied once, it was able to withstand sufficiently, and no flashovers were observed.

Example 1 Example 1 is an example when AC current is applied, but when the current changes over time in a stable manner with DC current, each of the five bodies has a 0.3
A case is shown in which mol % of bismuth oxide, chromium oxide, manganese oxide, and silicon oxide are contained, /, Q mol % of antimony oxide, cobalt oxide, and 0.0 q mol % of boric acid. Similarly, after mixing these powders thoroughly, granulating and molding/co00
Calcined at ℃. This was preliminarily heat treated, and then the relationship between the lifetime characteristics (Figure 6) and the conversion rate of body-centered cubic crystals was determined (Figure 7). Figure 6 of Shiuosha Jihata shows the charge rate go%.

It is a diagram showing the change in DC leakage current over time at an ambient temperature of 10θ°C, where curve E is for no heat treatment and curve F is for heat treatment at 400°C.
Heat treatment 1 curve G at °C is A! Curve aH is the case of heat treatment at θ°C and heat treatment at 100°C. FIG. 7 is a diagram showing the relationship between the annealing humidity (r° C.) and the conversion rate to body-centered cubic bismuth oxide determined from X-ray analysis when heated for 2 hours. In this case 10
It can be seen that a conversion rate to body-centered cubic crystals of 10% or more is desirable under heat treatment conditions of 0° C. or higher.

In this case, the working temperature range suitable for this condition is bro℃.
Use 7 liters of glass. In this case, the expansion coefficient of the element is almost the same as in Example 1, so the working temperature i
A temperature as high as 0°C is required. It was confirmed that the life characteristics against direct current similar to those shown in Fig. g were obtained, and that the withstand capacity was sufficient.

Although this method shows a method in which glass powder is melted with an organic binder and vitrified after being heated, the method of constructing the glass is not limited to this, and there are other methods that involve an increase in the number of work steps that are desirable. Other than that, any material that vitrifies or solidifies to form a high-resistance layer in the temperature range necessary to form the necessary body-centered cubic crystals may be used. As a method, there may be a method of mixing powder with a binder and wrapping it in a tape shape, or a method of immersing it in a molten glass bath (ゝO [Effects of the Invention] As described above, according to the present invention, Since the high-resistance layer is not overloaded and the high-resistance layer is not overloaded, the high-resistance layer can be reloaded at the same time, which greatly contributes to reducing the number of man-hours and improving the yield.

[Brief explanation of drawings]

Figure IC/a is a cross-sectional view of the voltage non-linear resistor according to the present invention, Figure 1) is a schematic diagram of the fine structure of the resistor body of the voltage non-linear resistor according to the present invention, and Figure λa is a cross-sectional view of the voltage non-linear resistor according to the present invention. A cross-sectional view of a non-linear resistor, Figure B is a schematic diagram of the fine structure of the resistor body of a conventional voltage non-linear resistor, and Figure 3 shows the leakage current ratio of a conventional voltage non-linear resistor. The hawk diagram is a diagram showing the relationship between the reheating temperature and the conversion rate to body-centered cubic bismuth oxide. ! Figure 6 shows the diffraction pattern, Figure 6 shows the change in DC leakage current over time, and Figure 7 shows the relationship between the annealing temperature and the conversion rate to body-centered cubic bismuth oxide determined by X-ray diffraction. It is a line diagram. In the figure. f/l is the electrode, (C) is the voltage nonlinear resistor body, (J)
(6) is a one-dimensional resistive layer of low-melting glass frit, (1) is a zinc oxide particle, (2) is a spinel particle, and (6) is a boundary layer mainly composed of bismuth oxide (a specified Sanete layer based on the proportion of body-centered cubic crystals). ), (ri) are side high resistance layers, and (g) is a boundary c grain) whose main component is bismuth oxide. Figure 10 Figure 2: Electric FL non-linear resistance amount 4: Ingredients (3 grains) ÷ 5: Subiki particles 6 (62) 1st (Ti) component + T) Boundary layer time (4) Mitsu 411o heat yl JL (”C) #) 5 Fig. 29 (deg,) Direct: Marumore electric moxibustion (7”A)

Claims (1)

[Claims] A voltage nonlinear resistor element is made by firing a raw material containing zinc oxide as a main component and at least bismuth oxide, and after sintering a high resistance layer on the side surface of this element, a predetermined amount of bismuth oxide is formed into a body-centered cubic crystal. In the manufacturing method of a voltage non-linear resistor which essentially consists of conversion, the sintering temperature range is the same as the conversion temperature range for converting a predetermined amount of bismuth oxide into a body-centered cubic crystal, and the voltage non-linear resistor is Resistor expansion coefficient and ±1
A voltage non-conductive device characterized in that a glass frit having expansion coefficients that match within 0% is applied to the side surface of the element, and heating forms a side high resistance layer and converts bismuth oxide into a body-centered cubic crystal at the same time. Method of manufacturing a linear resistor.