JPS5853481B2 - resistance composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistance composition, particularly a resistance composition used for a fixed resistor, a variable resistor, a resistor for a hybrid integrated circuit, a heating element for an electric heater, etc. Co
It is characterized by containing conductive fine powder made of either or both of 2S i and Co8i and a glass frit.

Conventionally, precision fixed resistors and resistors for hybrid integrated circuits have generally been manufactured using conductive fine powders of precious metals such as silver (Ag), palladium (Pd), or ruthenium oxide (RuO2), and glass frit. The following resistance composition is used.

Since a resistor using this composition is made of a noble metal or its oxide and glass frit, it is generally known as a resistor that has excellent heat resistance and power resistance, and is highly reliable.

However, since this resistor composition uses a noble metal such as Ag/Pd or ruthenium (Ru), or an oxide thereof, it becomes very expensive.

A major drawback of a resistive composition having a particularly low resistance value is that it requires a large amount of conductive fine powder, making it expensive and difficult to use in general-purpose inexpensive resistors.

On the other hand, resistor compositions that do not use noble metals include those that use conductive fine powder such as indium oxide or tungsten carbide and glass frit.

However, in both of these methods, when firing the resistance composition, it is necessary to fire it in an inert atmosphere such as nitrogen, which makes the firing process more complicated and the firing cost significantly higher than firing in air. Become.

Furthermore, the resistive characteristics were not necessarily satisfactory.

The present invention has been able to solve these problems, and by using conductive fine powder made of Co2Si or CoSi or a mixture thereof, and glass frit, a high-performance and inexpensive product can be produced. The present invention provides a resistance composition that can constitute a glazed resistor.

Hereinafter, the resistance composition of the present invention will be explained in detail.

The conductive fine powder is C 02 which is a compound of co and Si.
Consisting of S t or CoS i or a mixture thereof.

The conductive fine powder can be prepared by mixing fine powders of cobalt and silicon at a ratio of 2=1 (atomic ratio) or 1:1 (atomic ratio), and either leaving it as a powder or
Alternatively, after forming into a block shape, it is heat-treated and reacted at a temperature within the range of 800 to 1500°C in a vacuum or an inert atmosphere to generate Co2Si or CoSi, and then finely pulverized.

The mixing ratio of Co and Si is not necessarily limited to the stoichiometric composition ratio, and a slight deviation is not particularly problematic.

The conductive material is crushed using a stainless steel rod, then crushed using a grinder, and then placed in a pot with methanol and crushed using a ball mill.

A grinding time of about 24 to 240 hours is sufficient, but the grinding time may be longer if necessary.

Glass frit is made of, for example, boric acid (H2SO4):
51.3 weight cake, barium carbonate (BaC03): 34
．． 2% by weight, silicon oxide (SiO□): 3.4% by weight
, calcium carbonate (CaCOs): 2.55 weight rice cake and magnesium oxide (MgO): 2.55 weight rice cake were mixed, placed in an aluminum crucible, heated to a temperature of 1200°C to melt, and then poured methanol into the pot. The glass raw material, which is prepared by ball milling for 10 to 240 hours, turns into an oxide under melting conditions.

For example, H2SO4 becomes B2O3, BaCO3 becomes Ba
O, CaCO3 changes to CaO.

The particle size of the conductive fine powder and glass frit is preferably on the order of 0.1 to several microns.

Note that the glass frit is not necessarily limited to the above composition.

Next, the conductive fine powder and glass frit are mixed in an appropriate ratio, and an organic binder, such as a mixture of turpentine oil and ethyl cellulose in a ratio of 9:1 (weight ratio), is added in order to give printing properties. A paste-like resistance composition is prepared.

The appropriate amount of organic binder to be added is 5 g based on the log of the amount of conductive fine powder and glass frit, but as the amount of glass frit increases, it is better to slightly increase the amount of organic binder. It is.

This paste-like resistance composition was printed on an alumina porcelain substrate using a 200-mesh screen mesh,
After drying at 120℃, the maximum temperature is 700-900℃
A glazed resistor is made by incineration through a tunnel furnace heated to .

The electrodes used were Ag-Pd electrodes in which a paste containing Ag, Pd, and glass frit was screen printed, dried, and fired before printing and firing the resistor.

However, a gold electrode or a silver electrode may be used instead of the Ag Pd electrode.

Note that when there is no need to print the resistive composition on a ceramic substrate, for example, in the case of a body shape, an organic binder is not particularly required.

At this time, it was possible to make a resistor using only a mixture of conductive fine powder and glass frit by adding a small amount of water to this mixture, molding it, and heating it to a high temperature.

Examples will be described below.

Example l Co,! -8i fine powders were mixed at a ratio of 2:l (atomic ratio) and formed into a block, and then
A conductive material containing C02St as a main component was produced by heat treatment at ℃ for 2 hours.

This was finely pulverized to obtain a conductive fine powder.

Next, this conductive fine powder and glass frit were blended in the proportions shown in Table 1, and an organic binder was added to prepare a resistance composition.

This resistive composition was screen printed on an alumina porcelain substrate using a 200 mesh screen mesh.
After drying at 20℃, the maximum temperature is 850℃ or 80℃.
A resistor was produced by burning through a tunnel furnace heated to 0°C.

The film thickness after firing was about 15μ.

Table 1 shows the sheet resistance value at 25°C and the temperature coefficient of resistance measured between 25°C and 125°C.

The load life characteristics were evaluated by applying a load power of 12.5 mW71 td at an ambient temperature of 70°C for 15 hours and removing it for 0.5 hours, and evaluating the rate of change in resistance value after 100 hours. It was within ±1%.

In addition, the humidity characteristics are as follows: ambient temperature: 70°C, relative humidity: 90-95°C.
±1% resistance change rate after 1000 hours
It was within

In addition, samples 1 to 5 were made by ball milling Co2Si for 192 hours, and samples 6 to 8 were made by using C,02S s
was ground in a ball mill for 24 hours.

Example 2 Co and Si fine powders were mixed at a ratio of 1:1 (atomic ratio), formed into a block shape, and then heat treated at 1400°C in vacuum to form a conductive material containing CoSi as the main component. Had made.

This conductive material was ground in a ball mill for 24 hours to produce conductive fine powder.

Next, conductive fine powder and glass frit were blended in the proportions shown in Table 2, and an organic binder was added to prepare a resistive composition core.

This resistor composition was printed on an alumina ceramic substrate in the same manner as in Example 1, dried, and burned to produce a resistor.

Table 2 shows the area resistance value and temperature coefficient of resistance.

Further, the load life characteristics and humidity characteristics were measured in the same manner as in Example 1, and as a result, the resistance value change rate was within ±1% for all samples.

Example 3 Each fine powder of Co2Si (l!-CoSi) was blended in the proportions shown in Table 3, and an organic binder was added to prepare a resistance composition.

This resistor composition was printed on an alumina ceramic substrate in the same manner as in Example 1, dried, and burned to produce a resistor.

Table 3 shows the sheet resistance value at 25°C and the temperature coefficient of resistance measured between 25°C and 125°C.

Note that both CoSi and Co2Si were used after being ground in a ball mill for 24 hours.

The load life characteristics and humidity characteristics were measured in the same manner as in Example 1, and the resistance change rate was within ±1% for all samples.

As is clear from the examples above, a resistor using a resistive composition containing a conductive fine powder made of a mixture of nickel silicide and cobalt silicide and glass frit of the present invention has a low resistance value. can be obtained easily, has excellent resistance characteristics such as load life characteristics and humidity characteristics,
Since it is made of metal silicide and glass, it is nonflammable and can be fired in air to create a resistor.
Furthermore, it has many advantages such as being extremely inexpensive compared to noble metal-based resistance compositions made of Ag., Pd, RuO2, etc.

Therefore, it can be used not only for resistors and resistance networks for hybrid integrated circuits, but also for various fixed resistors and variable resistors for electric power and general use, as well as heating elements for electric heaters. It has a wide range of uses, including being able to be used as a kind of conductor.

Claims (1)

[Claims] 1 contains a conductive fine powder made of one type of Co2Si or CoSi or a mixture thereof, and a glass frit, and the weight ratio of the conductive fine powder and the glass frit is 1.
A resistance composition characterized in that the ratio is 0:90 to 80:20.