JPH0732081B2 - 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, these resistance pastes were applied on an insulating substrate such as alumina by screen printing and baked in air to be used as a resistor of a semi-fixed resistor.

However, when a slider is slid on this resistor, the resistor obtained by the above-mentioned resistor paste has
The resistance value showed a change of 30 to 50% from the initial value after about 100 rotations, and the stability was poor.

In addition, since the 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 it publicly known, but have found a resistance paste containing iron oxide-ruthenium oxide-lead oxide as a conductive component, and have made it practical.

With this resistance paste, the change in resistance value, especially when used as a resistor of a semi-fixed resistor, the rotation life characteristics are significantly improved, and even if the slider is rotated about 100 times, it is slightly smaller than the initial value. It was improved to show only resistance change within several percent.

(Problems to be Solved by the Invention) However, the resistance paste made of the improved conductive component has a narrow range of resistance values that can be obtained, and it is particularly difficult to obtain a resistor on the high resistance side.

(Object of the Invention) Therefore, while the present invention has a feature that a resistance paste having iron oxide-ruthenium oxide-lead oxide as a conductive component has, that is, a resistor having a small temperature coefficient of resistance can be obtained, An object of the present invention is to provide a resistance paste capable of obtaining a resistance value on the high resistance side.

(Means for Solving the 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 is composed of ruthenium, lead oxide, and titanium oxide or barium titanate.

Of these metal oxide powders, iron oxide, ruthenium oxide,
When lead oxide is the first constituent and titanium oxide or barium titanate 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 the lead oxide is converted to Pb ₃ O ₄ , each of the first constituents has a molar ratio of Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 0.6 to ₃ : 0.2 to 1. When titanium oxide or barium titanate is converted into TiO ₂ and BaTiO ₃ for the _second constituent, 0.5 mol or less (however, 0 mol is included, relative to 1 mol of the total amount of the first constituent). No) It consists of those contained.

Further, in the present invention, the metal oxide powder contains cobalt oxide as its third constituent. In this case, when cobalt oxide is converted into CoO, 0.1 mol or less (however, 0 mol
It is contained). In addition, cobalt oxide was added to Co ₃ O ₄
When converted to, the content of the first constituent is 0.5 mol or less (not including 0 mol) based on 1 mol of the total amount. In addition, cobalt oxide may be contained in the form of Co ₂ O ₃ .

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 1 mol, and RuO ₂ (molecular weight 133.068 = 1 mol) and Pb ₃ O ₄ (molecular weight 685.556 = 1 mol) are 0.6 mol per 1 mol of Fe ₃ O ₄ , respectively.
˜3: 0.2˜1 and blend in such a ratio of molar ratio. Regarding titanium oxide and barium titanate, which are the second constituents, they are converted into chemical formulas of TiO ₂ (molecular weight 79.90 = 1 mole) and BaTiO ₃ (molecular weight 233.24 = 1 mole), respectively. The total amount of Fe ₃ O ₄ , RuO ₂ and Pb ₃ O ₄ (if Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 1: 1, the total molecular weight is 105
2.174) as 1 mol and 0.5 mol or less (however, 0 mol
(Not including moles). Furthermore, for the cobalt oxide is the third component, (74.929 = 1 mol molecular weight) respectively CoO, in terms of Co ₃ O ₄ (molecular weight 240.786 = 1 mole), as in the second component, the first The total amount of Fe ₃ O ₄ , RuO ₂ , and Pb ₃ O ₄ (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 CoO, this is 0.1 mol or less (however, 0 mol is not included), and in the case of Co ₃ O ₄ , 0.5 mol or less ( However, 0 mol is not included).

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 component molar ratio of RuO ₂ with respect to O ₄ 0.6 to
The value of 3 is less than 0.6 because the temperature coefficient of resistance is ± 500 pp
This is because m / ° C is exceeded, while if it exceeds 3, electrical characteristics will not be a problem, but the amount of RuO ₂ will increase, the economic merit will disappear, and it will not lead to cost reduction. In addition, the molar ratio of Pb ₃ O ₄ is 0.2-
If the value is less than 0.2, there is no problem in electrical characteristics, but the amount of Pb ₃ O ₄ decreases, so the amount of RuO ₂ must be increased, resulting in cost increase. This is because the resistance value becomes too large and the temperature coefficient of resistance exceeds ± 500 ppm / ° C.

Next, the second constituents TiO ₂ and BaTiO ₃ were set to 0.5 mol or less with respect to 1 mol of the total amount of the first constituents because the resistance value becomes too high when the amount exceeds 0.5 mol and the predetermined resistance is exceeded. Value cannot be obtained, and the temperature coefficient of resistance is -500ppm.
This is because the temperature exceeds / ° C.

Furthermore, when the cobalt oxide, which is the third constituent, is converted to CoO, it is 0.1 per mol of the total amount of the first constituent.
The reason why the amount is less than 0.1 mol is that if the amount exceeds 0.1 mol, the temperature coefficient of the resistance value deteriorates again and exceeds -500 ppm / ° C.

Also, when converted to cobalt oxide Co ₃ O ₄ , the amount of CoO is 0.5 mol or less with respect to 1 mol of the total amount of the first component.
This is because the temperature coefficient of the resistance value deteriorates again in the same manner as.

The mixing ratio of the glass frit to the metal oxide powder is 30 to 70 wt% of the metal oxide powder, and the glass frit is 70 to 30 wt%. The glass frit amount is limited to this range by 70% for metal oxide powder.
If the content of the glass frit exceeds 30% by weight and the weight of glass frit is less than 30% by weight, the moisture resistance is deteriorated. This is because when used as a body, the rotational life characteristics deteriorate. Examples of the glass frit include lead borosilicate type glass frit.

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. In other words, if it is less than 25% by weight, the solid component will increase and a paste with good printability cannot be obtained. , Because the resistance value varies. 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. Glass frit is added to this metal oxide powder in a specified ratio, and TiO ₂ , BaTiO ₃ , cobalt oxide (CoO, Co ₃ O ₄ , Co ₂ O ₃ ) if necessary, and an organic vehicle are added and mixed to improve resistance. A paste is obtained. Other Ti
O ₂ , BaTiO ₃ , and optionally cobalt oxide (CoO, Co ₃ O ₄ , Co ₂ O
₃ ) 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 such as alumina, and is applied in air, for example.
It will be baked at a temperature of 700-900 ° C and will be configured as a resistor.

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

Example 1. Fe ₃ O ₄ , Ru which is the first constituent of the metal oxide powder
O ₂ and Pb ₃ O ₄ were mixed at the molar ratios 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. TiO ₂ and BaTiO _{3 as the second} constituents were added to this conductive powder in the ratios shown in Table 1.
And a lead borosilicate glass frit was 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 baking 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 202 ^F test method 304.

Those marked with * in the table are outside the scope of this invention.
Everything else is within the scope of this invention.

In Table 1, TiO ₂ or BaTi the _{Fe 2 O 3 -RuO 2 -Pb 3} O 4
It can be seen that the one containing O ₃ (Sample Nos. 2 to ₃ and 6 to 9) and the non-added one (Sample Nos. 1 and 5) respectively increased the sheet resistance value.

Further, in all of sample numbers 11 to 14, the molar ratio of the first constituent component is out of the range. Of these, sample No. 13 is characteristically satisfactory, but Ru
Since the amount of O ₂ is large and causes a cost increase, it was excluded from the present invention.

Example 2. Fe ₃ O ₄ , RuO ₂ which is the first constituent of the metal oxide powder
And Pb ₃ O ₄ were mixed at the molar ratios shown in Table 2, and then treated in the same manner as in Example 1 to obtain a conductive powder. In this conductive powder, Ti, which is the second constituent in the ratio shown in Table 2, is used.
O ₂ , BaTiO ₃ and CoO, Co ₃ O ₄ , Co ₂ O which are the third constituents
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.

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 shown in Table 3.

Similar to the first embodiment, those marked with * are outside the scope of the invention, and other than that are within the scope of the invention.

In Tables 2 and 3, Sample Nos. 15 to 19 show examples of resistance pastes used for variable resistors, and Sample Nos. 20 to 23 show examples of resistance pastes used as high-voltage resistors. Is shown.

Therefore, for sample numbers 15 to 19, the rotational life characteristics and sliding noise are additionally shown as the characteristic evaluation of the variable resistor.

In addition, for sample numbers 20 to 23, high voltage pulse characteristics and resistance voltage coefficient are shown as characteristics evaluation of high voltage resistors.

Among the respective characteristics, the rotation life characteristic is a value obtained by measuring the change in the resistance value after 100 rotations with respect to the initial resistance value by sliding the slider on the resistor.

The sliding noise is a value measured according to MIL-R-22097.

Further, the high voltage pulse characteristic is a value obtained by measuring the rate of change with respect to the initial resistance value by repeating the process of applying 7.5 KV for 1 second and keeping the unloaded state for 5 seconds 100 times.

Furthermore, the resistance voltage coefficient is the resistance value at the time of applying 50 V and 500
This is a value obtained by measuring the resistance value when V is applied and measuring the change in the resistance value per unit voltage.

By adding cobalt oxide from Tables 2 and 3, T.
Understand that CR can be controlled. It is also clear that the TCR can be controlled for all of CoO, Co ₃ O ₄ , and Co ₂ O ₃ for cobalt oxide. By the way, sample number 15
~ 18, Sample Nos. 20-22, and Sample Nos. 24-26, the TCR characteristics when cobalt oxide is not contained are 9.2 ppm / ° C (Sample No. 15) at -55 ° C, respectively.
Corresponding to ~ 18), -328.2ppm / ℃ (Sample No.20 ~ 2
2)), 47.6ppm / ° C (corresponding to sample numbers 24-26), and at + 150 ° C, -1037p each
pm / ° C (corresponding to sample numbers 15-18), -543.4ppm /
℃ (corresponding to sample number 20-22), -342.8ppm / ℃
(Corresponding to sample numbers 24-26). further,
By adding cobalt oxide from sample numbers 20-22,
It can be seen that the high voltage pulse characteristics can be improved. That is, in the example in which Co ₃ O ₄ was not added among the resistance pastes of the sample numbers 20 to 22, the high voltage pulse characteristic was −2.80%, while the sample numbers 20 to 22 of −0.56 to −0.91. %,
From this, the improvement effect by the addition of Co ₃ O ₄ is clear. For comparison, the area resistance value of the resistance paste of Sample Nos. 20 to 22 in which Co ₃ O ₄ is not added is 3.6 MΩ.
/ □, TCR: -328.2ppm / ℃ at -55 ℃, -54 at + 150 ℃
The resistance voltage coefficient was 3.4 ppm / ° C and -19.4%.

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

TiO ₂ , BaT as the _second component of the metal oxide powder
By adding and containing iO ₃ , the resistance value can be made larger than that without addition, and the sheet resistance value is 5 MΩ.
Resistors in the range up to / □ can be obtained.

Even if the resistance value is increased, resistance temperature characteristics, rotation life characteristics, and sliding noise characteristics are not deteriorated, and a resistor having no practical problem can be obtained.

By adding and containing cobalt oxide as the third constituent of the metal oxide powder, resistance temperature characteristics can be controlled, and further, high voltage pulse characteristics and the like can be improved.

Claims (3)

[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 titanium oxide or barium titanate. Among the metal oxide powders, when iron oxide, ruthenium oxide, and lead oxide are used as the first constituent components and titanium oxide or barium titanate is used as the second constituent component, iron oxide is added to the first constituent component. When converted to Fe ₃ O ₄ , ruthenium oxide converted to RuO ₂ , and lead oxide 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: 0.6 to ₃ : 0.2 to 1 When the titanium oxide or barium titanate is converted into TiO ₂ and BaTiO ₃ for the _second constituent, the total amount of the first constituent is 1 0.5 mol or less per mol (only , Not including 0 mol) resistive paste, characterized in that it contains. 2. 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, titanium oxide or barium titanate, and cobalt oxide. Of the metal oxide powder, iron oxide, ruthenium oxide, and lead oxide are the first constituent components, titanium oxide or barium titanate is the second constituent component, and cobalt oxide is the third constituent component. When the iron oxide was converted into Fe ₃ O ₄ , the ruthenium oxide was converted into RuO ₂ , and the lead oxide was converted into Pb ₃ O ₄ , the first constituents were Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 0.6 to ₃ : 0.2 to 1 composed of the following molar ratios, wherein titanium oxide or barium titanate is converted into TiO ₂ and BaTiO ₃ for the second constituent component. When converted respectively, The first constituent is contained in an amount of 0.5 mol or less (not including 0 mol) per 1 mol of the total amount of the first constituent, and when the cobalt oxide is converted into CoO for the third constituent. Based on 1 mole of total amount of ingredients
A resistance paste containing 0.1 mol or less (however, not including 0 mol). 3. 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, titanium oxide or barium titanate, and cobalt oxide. Of the metal oxide powder, iron oxide, ruthenium oxide, and lead oxide are the first constituent components, titanium oxide or barium titanate is the second constituent component, and cobalt oxide is the third constituent component. When the iron oxide was converted into Fe ₃ O ₄ , the ruthenium oxide was converted into RuO ₂ , and the lead oxide was converted into Pb ₃ O ₄ , the first constituents were Fe ₃ O ₄ : RuO ₂ : Pb ₃ O ₄ = 1: 0.6 to ₃ : 0.2 to 1 composed of the following molar ratios, wherein titanium oxide or barium titanate is converted into TiO ₂ and BaTiO ₃ for the second constituent component. When converted respectively, 0.5 mol or less based on the total amount to 1 mole of the serial first component (not inclusive of 0 mol) containing, for the third component, when converted to cobalt oxide Co ₃ O _4, the first A resistance paste containing 0.5 mol or less (excluding 0 mol) per 1 mol of the total amount of the constituent components of 1.