JPH0732082B2 - Resistance paste - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resistance paste containing iron oxide-ruthenium oxide-lead oxide as a main conductive component.

(Prior Art) It is known that there is a ruthenium oxide-based paste such as RuO ₂ or Bi ₂ Ru ₂ O ₇ as a resistance paste containing a metal oxide as a conductive component.

For example, it has been used as a resistor of a semi-fixed resistor by applying a resistance paste containing these components onto an insulating substrate such as alumina by screen printing and baking it in air.

However, when the slider is slid on this resistor, the resistance value of the resistance paste obtained by the above resistance paste is about 30 to 50% compared to the initial value after about 100 rotations.
%, And stable characteristics could not be obtained.

Further, since expensive RuO ₂ is the main component, it has been a factor of raising the price of the obtained resistor.

In order to solve such a problem, the inventors have not yet made public knowledge, but have found a resistance paste containing iron oxide-ruthenium oxide-lead oxide as a conductive component, and have been able to make it practical. .

This resistance paste contains iron oxide, ruthenium oxide, and lead oxide, which are metal oxide powders of conductive components, as Fe ₃ O ₄ , RuO ₂ , and P.
When converted into b ₃ O ₄ , the molar ratio of Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 0.6 to ₃ : 0.2 to 1 is obtained.

Then, according to this resistance paste, the change of the resistance value, especially in the case of the resistor of the semi-fixed resistor, the rotation life characteristic is significantly improved, even if the slider is rotated about 100 times,
It was possible to improve the resistance value to only show a change in resistance value within a few percent of the initial value.

(Problems to be solved by the invention) However, in the resistance paste containing the improved conductive component, the selection range of the obtained resistance value is approximately 1 KΩ / □ to 2 KΩ.
However, it was difficult to obtain a resistor having a low resistance value, specifically, a resistance value of 1 KΩ / □ or less.

(Object of the Invention) Accordingly, the present invention is a resistance paste containing iron oxide-ruthenium oxide-lead oxide as a main conductive component, which is inexpensive and has a low area resistance value, specifically, a resistance having a value of 1 KΩ / □ or less. It is intended to provide a resistance paste for obtaining a body.

(Means for Solving Problems) That is, the gist of the present invention is a resistance paste comprising a metal oxide powder, a glass frit, and an organic vehicle, wherein the metal oxide powder is iron oxide or oxide. It consists of ruthenium, lead oxide and vanadium oxide.

Of these metal oxide powders, iron oxide, ruthenium oxide,
When lead oxide is the first constituent and vanadium oxide is the second constituent, iron oxide is converted to Fe ₃ O ₄ and ruthenium oxide is converted to RuO ₂ for the first constituent. When converting lead oxide to Pb ₃ O ₄ , each first constituent component has a molar ratio of Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 1 to 3: 0.2 to 1, When vanadium oxide is converted into V with respect to the constituent components of, the total amount of the first constituent is 1 mol.
Containing 0.5 mol or less (however, not including 0 mol).

Further, in the present invention, the metal oxide powder contains any one of antimony oxide, titanium oxide and strontium titanate-based semiconductor powder as the third constituent. In this case, antimony oxide is Sb ₂ O ₃
When converted to, the content of the first constituent is 0.05 mol or less (not including 0 mol) based on 1 mol of the total amount. When titanium oxide is converted to TiO, it is 0.07 mol or less (however, with respect to 1 mol of the total amount of the first component).
(Not including 0 mol). Further, the strontium titanate-based semiconductor powder is contained in an amount of 30 parts by weight or less (not including 0 parts by weight) with respect to 100 parts by weight of the total amount of the first component.

Here, for each of the first and second constituent components, each oxide powder is represented by a chemical formula, and, for example, iron oxide is converted into the chemical formula of Fe ₃ O ₄ , which means that iron oxide is F
In addition to e ₃ O _4, to present in the form of _{Fe 2 O 3, Fe 2 O} 4 , etc. various oxides are those fixed to the specific oxide, and to allow determining the amount of that component.

In this case, in order to obtain the above-mentioned molar ratio, iron oxide is added to Fe ₃ O ₄
The molecular weight of 231.55 is defined as 1 mol, and RuO ₂ (molecular weight 133.068 = 1 mol) and Pb ₃ O ₄ (molecular weight 685.556 = 1 mol) are 1 to 1 mol of Fe ₃ O ₄ , respectively.
3: Mix in a molar ratio of 0.2 to 1. Regarding vanadium oxide, which is the second component,
Converted to the chemical formula of V (molecular weight 50.94 = 1 mol), the total amount of Fe ₃ O ₄ , RuO ₂ , and Pb ₃ O ₄ (Fe ₃ O ₄ : Ru) which are the first constituents
When O ₂ : Pb ₃ O ₄ = 1: 1: 1, the total molecular weight of 1052.174) is 1
The amount is a mole, and the amount is 0.5 mol or less (however, 0 mol is not included). Furthermore, regarding antimony oxide and titanium oxide, which are the third constituent components, Sb ₂ O
₃ (molecular weight 291.50 = 1 mol) and TiO (molecular weight 63.9 = 1 mol) are converted to Fe ₃ O ₄ , RuO ₂ , and Pb ₃ O ₄ which are the first constituent components in the same manner as the second constituent component. Total amount (Fe ₃ O ₄ : RuO ₂ : Pb ₃ O
_{In the case of 4} = 1: 1: 1, the total molecular weight of 1052.174) is 1 mol, and in the case of Sb ₂ O ₃ , it is 0.05 mol or less (however, 0 mol is not included), and in the case of TiO, it is 0.07 mol or less (however , Not including 0 mol).

Each of the first constituent components of the metal oxide powder described above,
The abundances of the second constituent component and the third constituent component are defined for the following reasons.

That is, for the first component is the basis of the Fe ₃ O ₄ content, the Fe ₃ O _4. 1 to the component molar ratio of RuO ₂ with respect to
The reason for setting 3 is that if it is less than 1, the resistance becomes too large, while if it exceeds 3, there is no problem in the electrical characteristics, but the amount of RuO ₂ increases and the economic merit disappears.
This is because it will not lead to cost reduction. Also, Pb ₃ O ₄
Regarding the component molar ratio of 0.2 to 1, the electrical characteristics are not problematic if it is less than 0.2, but the amount of Pb ₃ O ₄ is reduced, so that the amount of RuO ₂ must be increased, resulting in an increase in cost. On the other hand, if it exceeds 1, the resistance value becomes too large.

Next, when vanadium oxide, which is the second constituent, is converted as V, it is 0.5 per 1 mol of the total amount of the first constituent.
The reason why the amount is less than or equal to mol is that a low area resistance value is obtained in this range, but if it exceeds 0.5 mol, the area resistance value increases.

Further, among the third constituent components, antimony oxide is converted into Sb ₂ O ₃ and is set to 0.05 mol or less with respect to 1 mol of the total amount of the first constituent component because the temperature coefficient of resistance exceeds 0.05 mol. This is because it exceeds −500 ppm / ° C. The reason for defining the content of antimony oxide also applies to the respective contents of titanium oxide and strontium titanate-based semiconductor powder. The strontium titanate-based semiconductor powder is obtained, for example, by sintering SrTiO ₃ containing a minute amount of Y, Sb, Bi, Ta, W, or a rare earth element in a reducing atmosphere, and the ratio thereof. Resistance is 10 ⁰ -10 ^-1
Ω · cm or so is used.

Further, the mixing ratio of the glass frit to the metal oxide powder is 30 to 70% by weight of the metal oxide powder, and the glass frit is 70 to 30% by weight. The glass frit amount is limited to this range because the metal oxide powder exceeds 70% by weight, and the moisture resistance property deteriorates when the glass frit amount is less than 30% by weight, while the metal oxide powder is less than 30% by weight. If the glass frit amount exceeds 70% by weight, the rotational life characteristic deteriorates when used as a variable resistor, for example. Here, as the glass frit, for example, lead borosilicate type is used.

An organic vehicle is added to the solid component composed of the metal oxide powder and the glass frit to form a paste. The amount of the organic vehicle based on the above solid components is selected in the range of 25 to 35% by weight. This range is limited because printability is taken into consideration. That is,
If it is less than 25% by weight, the solid component is too large to obtain a paste with good printability. This is because the values vary.
As the organic vehicle, for example, ethyl cellulose to which α-terpineneol which is a solvent is added is used.

In order to prepare the resistance paste, Fe ₃ O ₄ , RuO ₂ , and Pb ₃ O ₄ , which are raw materials of the metal oxide powder, are weighed at a predetermined ratio, and each raw material is put into a pot mill together with water and mixed for a predetermined time. After that, water is evaporated and heat treatment is performed at 600 to 900 ° C. to obtain a metal oxide powder. By adding glass frit to the metal oxide powder in a predetermined ratio, and further adding any one of vanadium oxide, an organic vehicle, and if necessary, antimony oxide, titanium oxide and strontium titanate-based semiconductor powder, and mixing them. A resistance paste is obtained.
In addition, vanadium oxide, antimony oxide if necessary,
Any one of titanium oxide and strontium titanate-based semiconductor powder may be weighed and mixed with Fe ₃ O ₄ , RuO ₂ , and Pb ₃ O ₄ .

This resistance paste is applied by screen printing on an insulating substrate made of ceramic such as alumina or forsterite, and baked in air at a temperature of, for example, 700 to 900 ° C. to form a resistor.

(Examples) Hereinafter, the present invention will be described in detail based on Examples.

Example 1 Of the metal oxides, Fe ₃ O ₄ , RuO ₂ and Pb ₃ O _4, which are the first constituents, were compounded in a molar ratio shown in Table 1 and wet-mixed with water in a pot mill for 24 hours. . After that, water was evaporated, and the dry powder was put in a crucible and kept at a temperature of 700 ° C. for 2 hours to obtain a conductive powder. Vanadium oxide or organic vanadium oxide (V ₂ O ₃ , V ₂ O ₅ , VO (C ₅ H ₇ O ₂ ) ₂ , V (C ₅ H ₇
O ₂ ) ₃ ) was added, and lead borosilicate glass frit was further added. 28% by weight of an organic vehicle was added to these solid components and kneaded to prepare a resistance paste.

These resistance pastes were applied by screen printing between a pair of silver-baked electrodes formed in advance on the surface of an alumina substrate at intervals of 4 mm, and baked at 850 ° C. for 10 minutes.

The sheet resistance of the obtained resistor and the temperature coefficient of resistance (TCR) at −55 ° C. and + 150 ° C. were measured, and the results are shown in Table 1.

The temperature coefficient of resistance was measured according to MIL STD 202F test method 304.

Those outside the scope of the invention are shown in Table 1 as comparative examples.

Further, with respect to Sample Nos. 1-10 to 1-12 and Reference Examples 3 and 4, vanadium oxide was mixed with the first constituent component to prepare a resistance paste.

As is clear from Table 1, Fe ₃ O ₄ —RuO ₂ —Pb ₃ O ₄ with vanadium oxide added has a low area resistance value when the addition content range is 0.5 mol or less. It can be seen that is obtained.

Example 2 A metal oxide powder having the compounding ratio of Sample 1-11 in Example 1 was used, and any one of the third constituent components, antimony oxide, titanium oxide and strontium titanate-based semiconductor powder was added thereto. In addition to the proportions shown in Table 2, lead borosilicate glass frit was added. Add 28% by weight of organic vehicle to these solid components and knead,
The resistance paste was adjusted.

This resistor paste was treated in the same manner as in Example 1 to form a resistor on the alumina substrate. Then, the characteristics were measured in the same manner as in Example 1, and the results are also shown in Table 2.

Those outside the scope of the invention are also shown as comparative examples.

As is clear from Table 2, the temperature coefficient of resistance can be controlled by including the third constituent in the metal oxide powder. Specifically, the third constituent component contains vanadium oxide, which is the second constituent component, so that the temperature coefficient of resistance changed to the positive side can be changed to the negative side. Moreover, there is an advantage that there is no problem that the area resistance value is rapidly increased.

(Effect) As is apparent from the above embodiments, the resistor paste according to the present invention has the following effects.

Fe ₃ O, which is the first constituent of the metal oxide powder
_Since vanadium oxide was contained as a second constituent in ₄ , RuO ₂ , and Pb ₃ O ₄ , a sheet resistance value as low as 1 KΩ / □ was obtained.

Furthermore, by containing any one of the third constituent antimony oxide, titanium oxide, and strontium titanate-based semiconductor powder, the temperature coefficient of resistance of the second constituent vanadium oxide can be improved. The change to the plus side can be controlled to the minus side.

Further, even if the third constituent component is contained, there is no fear that the sheet resistance value will increase.

Claims (2)

[Claims] 1. A resistance paste comprising a metal oxide powder, a glass frit, and an organic vehicle, wherein the metal oxide powder comprises iron oxide, ruthenium oxide, lead oxide, and vanadium oxide. Of these, when iron oxide, ruthenium oxide, and lead oxide are used as the first constituent components and vanadium oxide is used as the second constituent component, iron oxide is converted to Fe ₃ O ₄ for the first constituent component, When ruthenium oxide is converted to RuO ₂ and lead oxide is converted to Pb ₃ O ₄ , each first constituent component has the following molar ratio: Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 1 to 3: 0.2 to 1 When the vanadium oxide is converted to V in the second constituent, 0.5 mol or less (however, 0 mol is not included) is contained per 1 mol of the total amount of the first constituent. A resistance paste characterized by: 2. A resistance paste comprising a metal oxide powder, a glass frit, and an organic vehicle, wherein the metal oxide powder is iron oxide, ruthenium oxide, lead oxide, vanadium oxide, and antimony oxide, titanium oxide, and Of any one of strontium titanate-based semiconductor powders, among the metal oxide powders, iron oxide, ruthenium oxide, and lead oxide are the first constituent components, and vanadium oxide is the second constituent component, When any one of antimony oxide, titanium oxide, and strontium titanate-based semiconductor powder is used as the third constituent component, iron oxide is converted to Fe ₃ O ₄ for the first constituent component to obtain ruthenium oxide. the terms of RuO _2, when converted to lead oxide Pb ₃ O _4, the first component consists of the following molar _{ratio, Fe 3 O 4: RuO 2} : Pb 3 O 4 1: 1 to 3: 0.2 to 1 With respect to the second constituent component, when vanadium oxide is converted to V, 0.5 mol or less (excluding 0 mol is not included with respect to 1 mol of the total amount of the first constituent component). ) Contains,
Regarding the third constituent component, antimony oxide is converted to Sb ₂ O ₃ and is 0.05 mol or less (however, 0 mol is not included) per 1 mol of the total amount of the first constituent component, and titanium oxide is Converted to TiO, 0.07 mol or less (however, not including 0 mol) relative to 1 mol of the total amount of the first component, and for the strontium titanate-based semiconductor powder, the total amount of the first component is 100 parts by weight. The resistance paste contains 30 parts by weight or less (however, not including 0 parts by weight).