KR20180092656A - Electrode paste for fuel sender and manufacturing method thereof - Google Patents

Abstract

The present invention relates to electrode paste for a fuel sender of a vehicle and to a manufacturing method thereof, and more specifically, to electrode paste for a fuel sender of a vehicle and to a manufacturing method thereof, wherein the electrode paste comprises further glass frit containing zinc oxide (ZnO) to improve the bonding and abrasion resistance of a conductive electrode material of palladium (AgPd) and a ceramic substrate.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode paste for a fuel sender,

The present invention relates to an electrode paste for a fuel sender of a vehicle and a method of manufacturing the same, and more particularly, to an electrode paste for a fuel sender containing zinc oxide (ZnO) for improving the bonding property and abrasion resistance of a conductive electrode material of silver palladium (AgPd) The present invention relates to an electrode paste for a fuel sender further comprising a glass frit and a method for producing the electrode paste.

The fuel sender assembly is attached to the fuel pump and located inside the fuel tank.

As shown in FIG. 1, the fuel sender assembly is composed of a brush, a substrate, and a plotter. In the case of the substrate portion, as shown in Fig. 2, a metal electrode is patterned and bonded onto a ceramic substrate.

The floater is located on the oil surface of the fuel, and the part where the brush and the metal on the substrate come into contact with each other is changed according to the movement of the plotter.

Depending on the position of the contact point between the brush and the substrate, the output resistance changes, allowing the amount of fuel to be sensed.

This output value is sent to the cluster so that the user can know the remaining amount of fuel.

Since the position of the plotter continuously changes in accordance with the oil level (fuel amount), the friction (sliding) of the brush with the surface of the electrode portion of the substrate is continuously repeated.

In the case of a brush, a metal-metal bond is strong and a relatively strong hardness material is used. However, in the case of an electrode part of a counter substrate, the bonding force is weak due to the metal-ceramic bond and the hardness is relatively weak. , Abrasion due to friction, and peeling often occur.

When abrasion and peeling of the electrode part occur, the ceramic substrate is exposed, and the electrode pattern is broken and electricity is not transmitted.

For this reason, the controller recognizes the output resistance as an infinite value, and there is a problem that the fuel amount is displayed as 0 to the user even though the fuel is present.

Fuel senders are divided into contact type and non-contact type. In case of non-contact type, expensive production cost is used only for special cases. Mostly, contact type fuel sender is used.

Currently, two types of materials are used for the electrode material of the contact type fuel sender, AgPd and AuPt.

However, AuPt is not widely used because it uses relatively expensive precious metals and most of them use AgPd.

When the Ag content in the AgPd alloy is high (80% or more), a chemical reaction easily occurs with the sulfur S present in the fuel, and as shown in Fig. 4, the quality problem due to impurities (silver sulfide) Increase).

In addition, since the hardness of the material is lower than that of the noble metal, abrasion due to sliding of the brush is easily caused.

On the other hand, when the content of Pd is high (more than 80%), the chemical resistance and abrasion resistance (high hardness), which is a disadvantage of the high Ag electrode, are excellent. However, the bonding property with Al ₂ O ₃ used as the substrate material is weak, And therefore, it tends to easily separate from the substrate after a certain level of wear.

As described above, when the bonding force is excellent due to the opposite physical property between Ag and Pd, the chemical resistance and the abrasion resistance are poor, and when the chemical resistance and the abrasion resistance are excellent, the bonding strength is poor.

Korean Patent No. 10-0435335 (Jun. 1, 2004)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to provide an electrode for a fuel sender which further comprises a glass frit containing zinc oxide (ZnO) for improving the bonding property and wear resistance of silver electrode material of silver palladium (AgPd) Paste and a method of manufacturing the same.

The electrode paste for fuel sender according to the embodiment of the present invention Conductive powder, glass frit.

The glass frit may be contained in an amount of 40 to 50% by weight.

In addition, the glass frit may include ZnO.

The ZnO may be added in an amount of 15 to 18% by weight based on 100% by weight of the electrode paste

And the like.

In addition, the glass frit may further include SiO ₂ , Al ₂ O 3, and Bi ₂ O ₃ .

The SiO ₂ may be contained in an amount of 2 to 3.5 wt% based on 100 wt% of the electrode paste.

The Al ₂ O ₃ may be contained in an amount of 4 to 7 wt% based on 100 wt% of the electrode paste.

The Bi ₂ O ₃ may be contained in an amount of 19 to 25% by weight based on 100% by weight of the electrode paste.

In addition, the conductive powder may contain 13 to 18% by weight of Ag and 31 to 68% by weight of Pd.

A method of manufacturing an electrode for a fuel sender according to an embodiment of the present invention includes the steps of printing an electrode paste according to any one of claims 1 to 9 on an insulating substrate, drying the printed electrode paste, And baking the paste.

In addition, the insulating substrate may be an alumina (Al ₂ O ₃ ) substrate.

The present invention has the effect of improving the bonding property and wear resistance of a ceramic substrate by constituting an electrode paste further comprising a glass frit containing zinc oxide (ZnO) in the conductive electrode material of silver palladium (AgPd).

1 is a view showing a fuel sender assembly to which an electrode paste for a fuel sender according to the present invention is applied;
2 is a photograph showing the substrate portion in the fuel sender assembly of Fig.
FIG. 3 is a photograph showing a problem in which an electrode part is detached from a substrate according to the prior art.
4 is a photograph showing a problem of an electrode part to which a high-content Ag paste according to the prior art is applied.
5 is a photograph showing the blurring phenomenon depending on the content of the glass frit.
6 is a photograph showing a thick and dense intermediate layer between an electrode and a substrate in an electrode paste for a fuel sender according to the present invention.
7 is a graph showing the measurement results of the wear depth for each composition of the electrode paste for a fuel sender according to the present invention.
8 is a photograph showing the microstructure of the bonding interface between the electrode paste for fuel sender and the substrate according to the present invention.
9 is a flow chart showing a method of manufacturing an electrode for a fuel sender according to the present invention.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best way And should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The electrode paste for a fuel sender according to an embodiment of the present invention may include a conductive powder and a glass frit. At this time, the conductive powder is an electrode material, and the glass frit is used for improving the bonding property between the electrode material and the insulator ceramic substrate.

At this time, it is preferable that the glass frit included in the embodiment of the present invention is contained in an amount of 40 to 50 wt%. If it is contained in an amount less than 40%, it is difficult to obtain the effect of improving the bonding property, and if it exceeds 50% by weight, a bleeding out occurs as shown in FIG. 5, . The glass frit may include ZnO, the _{SiO 2, Al 2 O 3,} Bi 2 O 3 may be further included.

As described later, the effect of improving the bonding property of the glass frit is mainly due to the effect of ZnO contained in the glass frit. In the electrode paste for fuel sender according to the embodiment of the present invention, ZnO is 15 to 18 wt% If less than 15% by weight is used, sufficient bonding force between the electrode paste and the substrate can not be ensured. If it is used in excess of 18% by weight, blurring may occur, .

At this time, SiO ₂ is contained in an amount of 2 to 3.5% by weight based on 100% by weight of the electrode paste, and Al ₂ O ₃ is contained in an amount of 4 to 7% by weight based on 100% by weight of the electrode paste. The Bi ₂ O ₃ may be contained in an amount of 19 to 25% by weight based on 100% by weight of the electrode paste. Also, the conductive powder preferably contains 13 to 18 wt% of Ag and 31 to 68 wt% of Pd.

The contents of each composition are shown in Table 1. At this time, in Comparative Example 1, the conventional composition was used.

Component (wt%) Ag Pd Glass Frit ZnO SiO ₂ Al ₂ O ₃ Bi ₂ O ₃ Total amount Comparative Example 1
(Present) 13-18 31 ~ 68 7 to 8 0.5 to 1.5 1.5! 2.5 9-10 About 20% Comparative Example 2 11-12 1-2 3 to 4 13-14 About 28% Comparison dP3 13-14 1.5 to 2.5 3.5 to 4.5 16-17 About 34% Example 1 15 ~ 16 2 to 3 4 to 5 19-20 About 40% Example 2 17 ~ 18 2.5 to 3.5 6 to 7 24-25 About 50% Comparative Example 4 19-20 3 to 4 8 ~ 9 25 to 30 About 55% Comparative Example 5 21-22 3.5 to 4.5 10 to 11 30 to 35 About 65% Comparative Example 6 13-14 0.5 to 1.5 1.5 to 2.5 9-10 Approximately 24% Comparative Example 7 15 ~ 16 About 26% Comparative Example 8 17 ~ 18 About 28% Comparative Example 9 19-21 About 30%

In the case of Comparative Examples 4, 5 and 9 in which ZnO is contained in 19 wt% or more of the total electrode paste, as shown in FIG. 5, bleed out occurs and it can not be applied to the fuel sender Respectively.

Table 2 below shows the bond strength between the electrode paste and the substrate.

After immersing in diesel at 60 ° C for 500 hours, the bonding strength test was performed. Solder was applied to the 3 × 3 cm electrode portion, and then the solder portion was pushed in the shear direction, and the area ratio of the peeled electrode portion was calculated. It can be confirmed that the average peel areas of Examples 1 and 2 were 7.82% and 6.28%, respectively, which greatly improved the bonding force as compared to Comparative Example 1.

Peel area (%) division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 #One 15.3 10.9 8.9 8.2 7.2 10.1 8.2 6.9 #2 14.8 13.4 8.7 6.9 6.1 8.8 7.6 8.5 # 3 13.9 12.7 9.2 7.4 5.1 9.1 7.8 7.7 #4 12.7 15.6 9.5 8.9 5.3 9.4 9.1 6.2 # 5 11.7 17.2 9.5 7.7 7.7 9.1 8.4 7.1 Average 13.68 13.96 9.16 7.82 6.28 9.3 8.2 7.3

Table 3 below shows an operation endurance test with a method of measuring the number of times when an output abnormality occurs under the conditions of a load of 13 gf and 1.2 Hz (maximum of 2 million cycles).

In the case of Examples 1 and 2, the number of operation durables was significantly increased compared to Comparative Example 1, which is a conventional composition, and the life span due to abrasion resistance can be confirmed through this.

Classification NO. Number of operations Complex operation duration Dry running duration Comparative Example 1 #One 510,000 1,000,000 #2 800,000 880,000 Comparative Example 2 #One 510,000 1,200,000 #2 2,000,000 880,000 Comparative Example 3 #One 800,000 1,000,000 #2 2,000,000 880,000 Example 1 #One 2,000,000 1,000,000 #2 2,000,000 1,000,000 Example 2 #One 2,000,000 1,000,000 #2 2,000,000 880,000

7, the wear depth of the fuel sender contact portion was measured after the reciprocating sliding movement of 2,000,000 times under the conditions of the loads 13 gf and 1.2 Hz.

At this time, P1 is a portion contacting the outer contact and P2 is a portion contacting the inner contact. Also, Full, 1/2, and Empty measured the abrasion depth at the abutted part when the fuel amount was Full, 1/2, Empty respectively. Comparative Example 2, Comparative Example 3 and Comparative Examples 6 to 8 confirmed that the wear depth was deeper than that of Comparative Example 1, which was a conventional composition, and Example 1 and Example 2 showed superior effects of Comparative Example 1, Respectively.

8 is a photograph showing the microstructure of the bonding interface between the electrode paste for fuel sender and the substrate according to the present invention.

Referring to FIG. 8, ZnO of the glass frit and Al ₂ O ₃ as a substrate element react with each other at the interface between the Al ₂ O ₃ substrate and the electrode paste to form ZnAl ₂ O ₄ having a spinel structure to improve bonding strength will be. The Zn oxide in the glass frit forms ZnAl ₂ O ₄ by chemical reaction at the high temperature with the alumina element of the substrate. Since this material has a thermal and chemical stability with a spinel structure, it improves the abrasion resistance relatively, It is confirmed that the electrode serves as a junction between the electrodes.

9 is a flowchart showing a method of manufacturing an electrode for a fuel sender according to the present invention. Referring to FIG. 9, the method of manufacturing an electrode for a fuel sender according to the present invention includes a step of printing an electrode paste having the composition as described above on an insulator ceramic substrate (S100), and drying the printed electrode paste (S300). In this case, it is preferable to use an alumina (Al2O3) substrate as the insulating ceramic substrate. This is to improve the bonding strength by forming ZnAl ₂ O ₄ having a spinel structure at the bonding interface as described above.

Although the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, The present invention is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and variations are possible within the scope of the present invention, and it is obvious that those parts easily changeable by those skilled in the art are included in the scope of the present invention .

100:
110: insulated substrate
120:
130; brush
200: Plotter
300: Fuel pump

Claims (11)

Electrode paste for fuel sender comprising conductive powder and glass frit. The method according to claim 1,
Wherein the glass frit is contained in an amount of 40 to 50 wt%. 3. The method of claim 2,
Wherein the glass frit comprises ZnO. The method of claim 3,
Wherein the ZnO is contained in an amount of 15 to 18% by weight based on 100% by weight of the electrode paste. 5. The method of claim 4,
Wherein the glass frit further comprises SiO ₂ , Al ₂ O ₃ , and Bi ₂ O ₃ . 6. The method of claim 5,
Wherein the SiO ₂ is contained in an amount of 2 to 3.5 wt% based on 100 wt% of the electrode paste. 6. The method of claim 5,
Wherein the Al ₂ O ₃ is contained in an amount of 4 to 7 wt% based on 100 wt% of the electrode paste. 6. The method of claim 5,
Wherein the Bi ₂ O ₃ is contained in an amount of 19 to 25 wt% based on 100 wt% of the electrode paste. The method according to claim 1,
Wherein the conductive powder comprises 13 to 18% by weight of Ag and 31 to 68% by weight of Pd. Printing an electrode paste according to any one of claims 1 to 9 on an insulating substrate;
Drying the printed electrode paste;
And firing the dried electrode paste. 11. The method of claim 10,
Wherein the insulating substrate is an alumina (Al ₂ O ₃ ) substrate.

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