JPH05298917A - Composition for conductive aluminum paste - Google Patents

Abstract

PURPOSE:To provide a composition for a conductive aluminum paste which has high oxidation resistance and conductivity even if fired in air. CONSTITUTION:A composition for a conductive paste consists of (i) 40-90wt.% of aluminum powder, (ii) 1-30wt.% of at least one kind of powders selected from carbon, germanium, tin, metal hydrides, and metal phosphides, and (iii) 9-40wt.% of glass powder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a conductive aluminum paste composition.

[0002]

2. Description of the Related Art Conventionally, as a conductive paste used for forming electrodes of resistor elements, ceramic capacitors, thermistors, varistors, gas discharge display tubes, etc., a conductive paste prepared by blending silver powder or the like as a conductor is used. A conductive silver paste is used. However, an electrode manufactured using such a silver paste causes a phenomenon (migration) in which silver components in the electrode move between each other due to an electric load during use. Moreover, when used as an electrode of a DC type gas discharge panel, there is a problem that silver and mercury added to the gas form amalgam. Therefore, in order to solve these problems, a conductive aluminum paste containing aluminum, which is a base metal, as a conductor has been developed.

However, in the above-mentioned conductive aluminum paste, aluminum as a conductor is easily oxidized by firing during electrode formation, and the oxide is generated in the electrode. Therefore, there arises a problem that the resistance value of the electrode is increased, that is, the conductivity is lowered. Therefore, when firing the above-mentioned conductive aluminum paste, it had to be fired in a reducing atmosphere.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composition for a conductive aluminum paste which has excellent oxidation resistance and can exhibit excellent conductivity even after firing in an air atmosphere. ..

In view of the above problems, the inventors of the present invention have made earnest studies, and as a result, when a specific metal or metal compound was added to a mixture of aluminum and glass and this was used for an electrode or the like, it was exposed to air atmosphere. It was found that the oxidation of the electrode due to the firing in the above was suppressed, and the present invention was completed.

That is, the present invention provides a composition for a conductive paste containing at least 40% to 90% by weight of (i) aluminum powder, and (ii) at least one selected from carbon, germanium, tin, a metal hydride compound and a metal phosphide compound. The present invention relates to a composition for electrically conductive aluminum paste, which comprises 1 to 30% by weight of one kind of powder, and 9 to 40% by weight of (iii) glass powder.

The present invention will be described in detail below.

First, aluminum powder is used as the first component. As this aluminum powder, for example, a commercially available aluminum powder or the like can be used.
The compounding amount is 40 to 90% by weight, preferably 60 to 80% by weight. If the amount is less than 40% by weight, the amount of aluminum as a conductor decreases, and the properties of the conductive aluminum paste deteriorate. On the other hand, if it exceeds 90% by weight, the amount of the binder that adheres the substrate and the conductor to each other decreases, and the adhesion between the substrate and the conductor decreases, which is not preferable. The particle size of the powder is usually 0.05 to 100 μm.
The degree. If the particle size is less than 0.05 μm, the powder is likely to be oxidized during storage or paste processing, and its stability is lost. On the other hand, if it exceeds 100 μm, it becomes difficult to perform uniform dispersion, and a stable electric resistance value cannot be obtained, which is not preferable.

As the second component, at least one powder selected from metal hydride compounds, metal phosphide compounds, carbon, germanium and tin is used. Here, the metal hydride compound is, for example, titanium hydride, zirconium hydride,
Lanthanum hydride, holmium hydride, cerium hydride,
Examples thereof include vanadium hydride, yttrium hydride, neodymium hydride, dysprosium hydride, erbium hydride, europium hydride, gadolinium hydride, hafnium hydride, lutetium hydride, neodymium hydride and ytterbium hydride. The metal phosphide compound is, for example, aluminum phosphide, boron phosphide, cadmium phosphide, cadmium phosphide, cobalt phosphide, cobalt phosphide, copper phosphide, iron phosphide, gallium phosphide, indium phosphide, indium phosphide. Examples include manganese trioxide, nickel phosphide, trizinc phosphide, and zinc phosphide. Further, carbon, germanium and tin preferably have a diamond crystal structure, and a commercially available reagent or the like can be used as long as it has this crystal structure. The compounding amount is 1 to 30% by weight, preferably 5 to 10% by weight. If it is less than 1% by weight, a sufficient addition effect cannot be obtained, and if it exceeds 30% by weight, the effect of suppressing the increase in resistance is rather decreased. The particle size of the powder is usually about 0.05 to 100 μm. If the particle size is less than 0.05 μm, the metal powder is easily oxidized during storage or processing, and the metal compound is easily decomposed. If the particle size is more than 100 μm, it is difficult to disperse uniformly and a stable electric resistance value is obtained. Is not obtained, which is not preferable.

Glass powder is used as the third component.
In this case, it is preferable that the glass powder that can be used has a softening point of usually about 350 to 500 ° C. The glass composition is not particularly limited, and examples thereof include lead borosilicate glass, zinc borosilicate glass, bismuth borosilicate glass, or Li ₂ O, Na ₂ O,
K ₂ O, BaO, CaO, MgO, ZnO, TiO ₂ ,
_{ZrO 2, Al 2 O 3,} NaF, a well-known components, such as P ₂ O ₅ 1
It is possible to use one kind or one containing two or more kinds. The compounding amount is 9 to 40% by weight, preferably 10 to 30% by weight.
If it is less than 9% by weight, the adhesion between the conductor-forming composition and the base material will be insufficient, and if it exceeds 40% by weight, the effect of suppressing the increase in resistance will be rather decreased. The particle size of the above powder is usually about 100 μm or less. If it exceeds 100 μm, it becomes difficult to disperse uniformly, and the resistance value increases, which is not preferable.

If the above three component powders are uniformly mixed,
The composition for conductive aluminum paste of the present invention is obtained. When using such a composition, it can be used as it is, but it is widely used as an epoxy resin, a cellulose resin dissolved in other organic solvent, an acrylic resin, a rosin resin, a high melting point fatty acid, or the like. When kneading with an organic vehicle (binder) to form an ink into a paste form, suitable printing can be performed. The printing in this case can be performed according to the same method as that for normal pattern printing.

The materials to which the composition of the present invention can be applied include
The material is not particularly limited as long as it has a heat resistance of about 400 ° C. or more, and it can be applied to virtually any material. Among these, in particular, soda-lime glass, quartz glass, borosilicate glass, lead borosilicate glass, and other glasses, alumina-based ceramics, zirconia-based ceramics, barium titanate-based ceramics, zinc oxide-based ceramics, beryllia-based ceramics, forsterite-based Ceramics, magnesia-based ceramics, oxide-based ceramics such as lead zirconate titanate-based ceramics,
It is most suitable for non-oxide ceramics such as silicon nitride, silicon carbide and aluminum nitride.

[0013]

The composition for conductive aluminum paste of the present invention is excellent in oxidation resistance and can exhibit excellent conductivity even when fired in an air atmosphere. Therefore, a resistor element, a ceramic capacitor, It is optimal as a material for forming electrodes of various electronic parts such as thermistors.

[0014]

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

Examples 1 to 20 Aluminum powder (particle size: about 3 μm, spherical particle) and glass powder (B ₂ O ₃ 16%, SiO ₂ 10%, PbO66).
%, ZnO 8%, softening temperature 485 ° C.), and carbon, germanium, tin, titanium hydride powder, holmium hydride powder or aluminum phosphide powder in a composition as shown in Table 1, and an ester as an organic vehicle is added thereto. A solution of a cellulosic resin in a system organic solvent was added and kneaded to form an ink into a paste.

Next, this paste was printed on a soda-lime glass substrate with a 250 mesh (emulsion thickness of 15 μm) screen to form a circular pattern having a diameter of 1.5 cm according to a conventional method, and the paste was baked at 580 ° C. for 10 minutes to prepare a sample. It was created.

Next, the sheet resistance value of the obtained sample was measured. The results are shown in Table 1.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

Examples 21 to 25 Aluminum powder (particle size of about 3 μm, flaky particles) and glass powder (B ₂ O ₃ 16%, SiO ₂ 10%, PbO 66%,
ZnO 8%, softening temperature 485 ° C.) and carbon, germanium or tin are mixed in a composition as shown in Table 2, and a cellulose resin is added to an ester organic solvent as an organic vehicle and kneaded to form an ink. It was made into a paste.

Next, this paste was printed on a soda-lime glass substrate with a 250 mesh (emulsion thickness of 15 μm) screen to form a circular pattern having a diameter of 1.5 cm according to a conventional method, and this was baked at 580 ° C. for 10 minutes to prepare a sample. It was created.

Then, the sheet resistance value of the obtained sample was measured. The results are shown in Table 2.

[0025]

[Table 5]

Comparative Examples 1 to 3 As shown in Table 3, the sheet resistance value of the sample obtained in the same manner as in Example 1 was measured for the composition outside the range of the composition of the present invention. The results are shown in Table 3.

[0027]

[Table 6]

Comparative Examples 4 to 5 As shown in Table 4, the sheet resistance value of the sample obtained in the same manner as in Example 21 was measured for the composition outside the range of the composition of the present invention. The results are shown in Table 4.

[0029]

[Table 7]

From the above results, it is understood that the sample obtained from the composition of the present invention has a low sheet resistance value and exhibits excellent conductivity.

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Claims (1)

[Claims] 1. A composition for a conductive paste comprising: (i) aluminum powder 40 to 90% by weight (ii) at least one powder selected from carbon, germanium, tin, metal hydride compounds and metal phosphide compounds. 1-30 weight% and (iii) glass powder 9-40 weight%, The composition for electroconductive aluminum pastes characterized by the above-mentioned.