JP3362430B2 - Conductive paste - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive paste, and more particularly, to a conductive paste used for forming external electrodes of a ceramic electronic component such as a multilayer ceramic capacitor. 2. Description of the Related Art For example, when a ceramic electronic component is manufactured by forming an external electrode (thick film electrode) on a ceramic electronic component element such as a multilayer ceramic capacitor element, the conventional technique has been proposed. , Mainly platinum (Pt), palladium (Pd), silver (Ag), Ag-P
Precious metals such as d alloy or their alloys (precious metal alloys)
An external electrode is formed by applying a conductive paste using the above powder as a conductive material to a predetermined position of the ceramic electronic component element and firing the same. [0003] However, the above conductive paste is composed of Pt, P
Since expensive precious metals such as d, Ag, and Ag-Pd alloys or powders of the alloys are used as the conductive material, desired characteristics can be obtained, but there is a problem that the cost is increased. There is also a method of forming an external electrode using a conductive paste using a powder of a base metal such as Cu or Ni which is inexpensive as compared with the above-mentioned noble metal. For example, in the case of a multilayer ceramic capacitor, there is a problem that the capacity acquisition rate after a moisture resistance test is significantly reduced, and sufficient characteristics cannot be obtained. The present invention has been made to solve the above-mentioned problems, and is an electroconductive material capable of forming an external electrode of a ceramic electronic component having excellent moisture resistance without using an expensive noble metal material as an electroconductive material. It is intended to provide a paste. [0006] In order to achieve the above object, the present inventors conducted various experiments and studies, and conducted a conductive test using a material containing Cu as a main component and containing Zn and Sb therein. The inventor found that forming an external electrode of a ceramic electronic component using a conductive paste as a material would form an external electrode having excellent moisture resistance, and further conducted experimental studies to complete the present invention. That is, the conductive paste of the present invention contains copper (Cu), zinc (Zn), and antimony (Sb) as metal components, and contains Zn and
The proportion of each of Sb is 5% by weight or more, and Zn and S
The ratio of the total amount of b is 30 wt% or less material and conductive material, a conductive material, characterized in that to together kneaded with a binder over the paste. [0008] In the conductive paste of the present invention, Pt, Pd,
Since no noble metals such as Ag and Ag-Pd alloys are used and base metals Cu, Zn and Sb are used, it is possible to reduce raw material costs and reduce costs. Further, the base metals Cu, Zn, and Sb
Is used as a metal component, but the moisture resistance is improved by adding Sb, so that Pt, Pd, Ag, Ag
An electrode having moisture resistance that is not much different from the case of using a conductive paste containing an expensive noble metal powder such as a Pd alloy as a metal component can be formed. In the conductive paste of the present invention, as a raw material of Cu, Zn, and Sb, a metal powder, an alloy powder, a surface treatment powder, an organic metal, a metal alkoxide, and other various raw materials are used. Is possible. The ratio of Zn and Sb in the metal component (that is, the ratio of the total amount of Zn and Sb to the entire metal component) is preferably 30% by weight or less. %, The moisture resistance deteriorates. Further, it is preferable that the blending ratio of Zn of Zn and Sb is 15% by weight or more. this is,
When Zn is 15% by weight or more, the oxidation resistance is improved. It is preferable that the mixing ratio of Sb is 5% by weight or more. This is because when Sb is 5% by weight or more, the oxidation resistance is improved. Examples of the present invention will now be described together with comparative examples, and features thereof will be described in more detail. First, as a conductive material (conductive component), C
u, Zn, and Sb metal powders are blended in proportions as shown in Table 1. Then, use this compounded metal powder as a binder,
A conductive paste is prepared by kneading with a solvent and a glass frit by a roll mill. Ethyl cellulose was used as a binder, and butyl carbitol was used as a solvent. These binders and solvents are known materials generally used for conductive pastes. Further, as the glass frit, a zinc borosilicate-based glass frit which is also generally used for a conductive paste was used. For comparison, a conductive paste of a comparative example was prepared by using the conductive materials shown in Table 1 and in the same manner as in the above example. In addition, binder, solvent,
The same glass frit as that of the conductive paste of the above embodiment was used. Then, a predetermined internal electrode pattern is formed on a green sheet made of a dielectric ceramic by using a conductive paste (Ni paste) for forming an internal electrode (Ni electrode), and a plurality of the green sheets are laminated. After being pressed and crimped, cutting is performed at a predetermined position to cut out individual multilayer chips (multilayer ceramic capacitor elements). After firing at a predetermined temperature,
The above conductive paste is applied for about several tens of μ so as to connect to the internal electrodes exposed on both end surfaces of the multilayer ceramic capacitor element.
Apply to a thickness of m. Then, the multilayer ceramic capacitor element coated with the conductive paste is fired in a predetermined firing atmosphere in which the oxygen partial pressure is adjusted to form external electrodes. Then, the multilayer ceramic capacitor (sample) thus prepared is placed in a beaker, boiled at 100 ° C. in water (hot water), boiled for about 17 minutes, and then measured for a capacitance value. Was measured and compared with that immediately after baking (ie, before immersion in boiling water). Table 1 shows the measurement results of the moisture resistance thus performed. Table 1 also shows the measurement results of the comparative examples. [Table 1] The moisture resistance in Table 1 was evaluated by giving ◎ to particularly good samples, ○ to normal or slightly good samples, Δ to slightly poor samples, and × to clearly poor samples. As shown in Table 1, in the multilayer ceramic capacitor having the external electrodes formed by using the conductive paste of the comparative example (conventional example), the change width of the capacitance value before and after immersion in hot water was large. Although it is large, it can be seen that in the multilayer ceramic capacitor in which the external electrodes are formed using the conductive paste of the present invention, the change width of the capacitance value before and after immersion in hot water is small. As described above, the reason why the external electrode formed using the conductive paste of the present invention is excellent in moisture resistance is that Sb used as a conductive component is less ionizable than Zn, and It is considered that the use of a combination of Sb and Sb results in the formation of an electrode film having stable moisture resistance. In the above embodiment, the case where the external electrodes of the multilayer ceramic capacitor are formed by using the conductive paste of the present invention has been described. However, the conductive paste of the present invention is not limited to other ceramics requiring moisture resistance. The present invention can also be applied effectively when forming external electrodes of electronic components. As described above, the conductive paste of the present invention contains Cu, Zn, and Sb as metal components, and the respective proportions of Zn and Sb in the metal components are reduced.
5 is a% by weight or more, the material ratio of the total amount of Zn and Sb is 30 wt% or less and a conductive material, since a paste together kneading the conductive material and the bar <br/> inductor over ,
By using this conductive paste, external electrodes having excellent moisture resistance can be reliably formed on a ceramic electronic component element such as a multilayer ceramic capacitor element. Then, in this conductive paste, Pt, P
Since a base metal such as Cu, Zn, and Sb is used without using a noble metal such as d, Ag, or an Ag—Pd alloy or an alloy thereof, it is possible to obtain a conductive paste that is excellent in economical efficiency while suppressing raw material costs. Can be. Further, as metal components, Cu, Zn, Sb
Since base metals such as are used, baking at a low temperature becomes possible, and a baking apparatus and a baking process are simplified,
Energy consumption (electricity for electric furnaces, etc.) can be reduced to reduce costs.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-24821 (JP, A) JP-A-3-94409 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 1/22

Claims (1)

(57) Claims 1. Copper (Cu), zinc (Zn), and antimony (Sb) are contained as metal components, and the respective proportions of Zn and Sb in the metal components Is 5% by weight or more
, And the percentage of the total amount of Zn and Sb is 30 wt% or less material and conductive material to the conductive material and characterized in that as a <br/> monitor kneaded with a binder over a paste Conductive paste.