JPS5933241B2 - Glaze resistance material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glaze resistance material, and an object thereof is to provide a glaze resistance material that can be provided on a metallized alumina substrate obtained by simultaneously firing wiring electrode waste.

As a resistance material provided on an alumina substrate on which electrodes are formed, RuO2 glaze resistors made of Rub and glass components are widely used in practical use.

This glazed resistor is prepared by baking an electrode made of silver or silver and palladium in air on a sintered alumina substrate, and then baking it in air at a temperature of 750 to 900°C. W) 6 or molybdenum (
MO) cannot be used as an electrode on an alumina substrate (metallized alumina substrate) with wiring formed at the same time as the sintering of alumina.

W and MO are sensitive to oxidizing atmospheres, and the oxygen partial pressure in the atmosphere during resistance firing must be kept low.

However, RuO□, which is the main component of the resistor material, is easily reduced to Ru metal by firing in an atmosphere with a low oxygen partial pressure, such as green gas, and loses its properties as a resistor.

Therefore, the resistance material that can be formed on the metallized alumina substrate must be composed of thermodynamically stable components, in other words, components that do not undergo redox even in a hydrogen atmosphere.

On the other hand, silicide glaze resistance materials consisting of silicide and glass can be fired in air and at the same time.

Due to the nature of silicide, it is stable even in a reducing atmosphere without undergoing any chemical changes, so it can be fired even in a reducing atmosphere.

However, glaze resistance materials are generally made by adding, in addition to conductor components and glass components, an appropriate amount of a binder together with a solvent for the purpose of forming a printed film, and kneading the mixture into a paste.

In this way, when a printed film containing an organic binder as a binder is fired in a reducing atmosphere, most of the organic binder scatters due to thermal decomposition, but some of it is carbonized and remains as carbon in the resistive film, increasing the resistance. It has a great negative effect on the physical characteristics of the body.

Therefore, on the metallized substrate. When attempting to provide a glazed resistor, a major problem remained is how to completely remove the organic binder from the resistor paste.

One method is to decompose the binder at a relatively low temperature.
Since the binder burns, it is conceivable to keep the atmosphere oxidizing (for example, air) before the resistance firing process, to sufficiently burn the binder, and then return it to a reducing atmosphere to form the resistance.

However, even if the temperature in this binder removal step is low, oxidation of the electrode surface is unavoidable, and this method is not preferred.

For the reasons explained above, the reality is that circuit boards for which it is impossible to form a glazed resistor by firing in a reducing atmosphere, such as circuit boards in which a glazed resistor is provided on a metallized alumina substrate, are not put into practical use. .

The present invention realizes a metallized alumina circuit board having a glazed resistor by providing a glazed resistive material that has excellent resistance characteristics even when resistive firing is performed in a reducing atmosphere.

Its characteristic feature is that it contains 0.1 to 10 mole of at least one of molybdenum oxide or tungsten oxide in addition to silicides such as molybdenum silicide and tantalum silicide as a conductor component of the silicide-based glazed resistor. .

A detailed explanation will be given below based on Examples and Comparative Examples.

[Example 1] A silicide having a composition with a mole ratio of MoSi2 and TaSi2 of 3=1 was synthesized in vacuum at a temperature of 1400°C,
Add 0.1 to 10 mol of M2O3 and WO2 to this, grind in methanol to an average particle size of 2μ,
It was dried to obtain a conductive material.

In addition, Bad, B2O3, MgO, Cab, 5i02
A glass frit consisting of a glass frit having a weight coefficient of 50 to 94 days relative to the total amount of the conductor material was made into a glaze resistance powder, and turpentine oil in which 10 parts of ethyl cellulose was dissolved was added as a vehicle and kneaded to make a glaze resistance paste. .

This glaze resistance paste was printed on an alumina substrate with electrodes made of W or Mo, and after drying at 120°C for 10 minutes, a hydrogen atmosphere tunnel was created in which the maximum temperature was 850°C and the sample passed through the maximum temperature for 10 minutes. Fired in a furnace.

As a result of examining the thus obtained glazed resistor by changing the aspect ratio, it was found that the matching with the electrode was extremely good, and the moisture resistance of the resistor was as follows: The rate of change was within ±2 coefficients.

Table 1 shows the area resistance values R of these glazed resistors.

(mΩ/mouth), temperature change rate TCR (ppm) by resistance value measurement at 20°C and 125°C, noise (dB), and 500 (mW/mlt) as short-term load characteristics.
The resistance change rate ΔR/R (%) after application for seconds is shown.

[Example 2] Mo S 12 t T a S i2 and Mg2
A silicide with a Si molar ratio of 3:i:i was synthesized at 1200°C in vacuo, and then MoO2 and WO
A conductive material was obtained by adding 0.1 to 10 moles of each of 3 to the mixture, pulverizing the mixture in methanol to an average particle size of about 2 μm, and drying.

A glazed resistor was produced in the same manner as in Example 1.

Its initial characteristics are shown in Table 2. [Comparative Example] In order to clarify the effects of the present invention, in Examples 1 and 2, a conductive material containing neither MoO2 nor WO3 was obtained under the same conditions as in each Example, and a glaze resistor was prepared using the same procedure. I made a body.

Typical characteristics of each are shown in Table 3.

From Tables 1 and 2, it can be seen that Mo Si according to the present invention
2-TaSi 2-MeO2 (Me=Mo, W) based silicide glaze resistor has a resistance of several tens of ohms to 5 ohms when fired in a hydrogen atmosphere.
/mouth range, also MoS i2- TaSi2-M
g2 S i −MoO3 (Me = Mo p W )
It can be seen that the silicide-based glaze resistor exhibits favorable resistance characteristics in the medium resistance range.

Table 3 showing comparative examples shows that these excellent resistance characteristics can only be obtained by adding molybdenum oxide and tungsten oxide to the conductor material.

This is because the molybdenum oxide and tungsten oxide that have been added in advance are oxidized by the carbon left inside the glaze in a reducing atmosphere through a reaction of 3C+Me03-+3CO+Me (Me=Mo, W). It is considered that equivalent characteristics can be obtained.

Therefore, although it varies depending on the amount of resin contained in the resistance paste and the firing temperature, if molybdenum oxide or tungsten oxide is small, the combustion of C will be insufficient, and if it is too large, the resistance value of the silicide conductor and the glass Flowability is adversely affected and resistance properties are reduced in both cases.

The figure shows a typical example of the relationship between the amount of MoO3 and the short-time load characteristic, which is the most effective among resistance characteristics.

As explained above, the present invention provides a metalized glaze resistor having excellent properties in reducing atmosphere firing by containing at least one of molybdenum oxide and tungsten oxide in a silicide-based glaze resistor material. It is possible to produce an alumina substrate.

[Brief explanation of the drawing]

The drawing shows a typical relationship between the amount of MoO3 and the short-term load characteristics in the glaze resistance material of the present invention.

Claims (1)

[Scope of Claims] 1. The conductive material is composed of a conductive material and glass, and the conductive material is composed of at least silicides consisting of molybdenum silicide and tantalum silicide, as well as molybdenum oxide (MoO2), tungsten oxide (WO,), or both. .1~1
A glaze resistance material characterized in that it contains 0 molar coefficient. 2. The glaze resistance material according to claim 1, wherein the silicide is composed of molybdenum silicide, tantalum silicide, and magnesium silicide.