JPS58225503A - Method of producing conductive composite powder - 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 The present invention relates to a method for producing a composite powder having a uniform fine particle size and excellent conductivity.

Generally, when manufacturing thick film integrated circuits, for example, after coating a resistor paste on an alumina substrate,
The process of firing at a temperature of 0''C to form a thick film resistor is carried out, and these resistor pastes are mainly composed of Af powder or ruthenium oxide (hereinafter referred to as Ru5t) powder. A combination of glass powder and an organic resin solvent is used. However, when using a resistor paste whose main component is AP powder, the temperature change in the resistor is 300 ppm/" In contrast, when using a resistor whose main component is RuO (-st), the temperature change of the resistor is 1100pp.
The former is preferable because it is not only low in noise (lower than /"c"), but also generates less noise, and by adjusting the blending ratio, the surface resistance can be changed from 1Ω/low to IM,/lower. In comparison, the latter resistor paste containing RuO2 powder is currently more widely used in practical use.

Furthermore, in addition to being used in the production of thick film resistors, the Ru0v powder is also used as a catalyst in the hydrogenation of ascetic compounds, the hydrogenation of carbunyl groups in ketones and aldehydes, and the like.

Rub has been conventionally used in the fields mentioned above.

The powder manufacturing method is as follows: (a) Gold A A method of crushing Ru and oxidizing it.

(b) A method of thermally decomposing ruthenium chloride.

(C) A method in which an alkali is added to a ruthenium chloride solution and the resulting ruthenium hydroxide is thermally decomposed.

However, in the above methods (a) and (b), the particle size of the Rub2 powder produced is relatively large, and therefore, when used in the above resistor paste, for example, it has poor dispersibility. On the other hand, according to method (c) above, it is possible to produce uuOt powder with a fine particle size, but the grain size may not be agglomerated, and it is difficult to make a homogeneous paste. RuO produced by any method has problems such as unevenness.
, powder also has drawbacks such as being extremely expensive.

Therefore, the present inventors developed the conventional Rub as described above.

As a result of research to solve the problems of powder manufacturing methods, we have developed an average particle size of 0.1 to 1, which is easy to refine and size.
．． A suspension of titanium oxide (hereinafter referred to as TiO2) powder having 0 μmk, preferably at a rate of 20 to 1000 f/l, in water is heated and stirred, and the value of 1 to 1 is adjusted to 2 to 7. However, RuCLB is preferably 2
A solution dissolved in water, an aqueous hydrochloric acid solution, or alcohol is dropped at a rate of 0 to 200 l/l to precipitate Rub on the surface of the Tie powder by hydrolysis, and then it is separated in a furnace. Washed and finally the precipitated RuO2
In order to convert a small amount of ruthenium hydroxide contained in the powder into RuO, the surface of the Tie powder is coated with RuO, which is strongly chemically bonded to the powder by heating and baking, preferably at a temperature of 600 to 800°C. A composite powder having a layer is obtained, and as a result, the composite powder 1 has a layer of
Rub, preferably Rub, / (R
The amount of RuO2 in the range of 15 to 50 in terms of weight ratio of uO, + 'rib,) provides excellent electrical conductivity.
Furthermore, they found that since the amount of RuO, which is expensive, is relatively small, the cost is low.

This invention was made based on the above knowledge, and the reason why the manufacturing conditions were limited to the above-mentioned standard will be explained below.

(a) Average particle size of TiO, the average particle size of powder commonly used as a pigment is (1,1
~1.0/Am, so the average particle size is set to 0.1
It was determined to be ~1.0 μm.

(b) One value of the solution If the value is less than 2, the hydrolysis is incomplete and unreacted ruthenium chloride remains in the solution, while if the value exceeds 7, the Tie, powder surface Rub to the top! The pJl value was determined to be 2 to 7 because the precipitation of .

Next, the method of the present invention will be specifically explained using examples.

Example Tie, semi-uniform particle size of powder, proportion of T i Ot in one suspension liquid, heating temperature of suspension, type of ruthenium chloride dissolved solution, proportion of ruthenium chloride in the solution, ruthenium chloride dissolved solution The volume ratio of the suspension and the reaction solution, and the heating and firing temperature of the composite powder were set to the conditions shown in Table 1. Under these conditions, the ruthenium chloride was dissolved in the suspension containing the Tie2 powder. The solution is added dropwise while heating and stirring and adjusting the value to precipitate Rub on the surface of the Tie and powder by hydrolysis, and the resulting composite powder is separated in a furnace, washed, dried, and heated. Composite powders 1 to 11 of the present invention were manufactured by firing, respectively.

Further, the specific resistances of the composite powders 1 to 11 of the present invention obtained as a result are shown in Table 1.

From the results shown in Table 1, composite powders 1 to 11 of the present invention are all Rub, specific resistance of powder: 2 × 10-20
・It has a specific resistance that is almost the same as that of the image, and it is clear that it has excellent conductivity.

As described above, according to the method of the present invention, a composite powder having fine and uniform particle size and excellent conductivity can be produced at a low cost, and the resulting composite powder can be used for example. It brings industrially useful effects such as excellent performance in the production of thick film resistors for thick film integrated circuits and when used as a catalyst.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Oro Husband

Claims (1)

[Claims] A suspension of titanium oxide powder having an average particle size of 0°1 to 1.0 μm is heated and stirred, and while adjusting the value to 2 to 7, ruthenium chloride is added to water and hydrochloric acid. An aqueous solution or a solution dissolved in alcohol is dropped onto the surface of the titanium oxide powder to precipitate ruthenium silica by hydrolysis, and then the ruthenium oxide is separated from each other, washed, and heated to sinter to form titanium oxide powder. 1. A method for producing a conductive composite powder, which comprises producing a composite powder having a ruthenium oxide coating layer on its surface.