Contact material suitable for slider for fuel sender, and slider for fuel sender

Abstract

Proposed is a contact material constituting a slider for a fuel sender, the slider moving on a conductor in conjunction with a float moving in accordance with a liquid level, wherein the contact material includes 10 to 25 mass % of nickel and a balance of palladium. The present contact material is useful in the light of material cost in addition to corrosion resistance and durability. The fuel sender is useful for vehicles, such as FFV, using composite fuel of alcohol and the like. The present invention allows for producing a slider for a fuel sender having excellent corrosion resistance and abrasion resistance.

Claims

1. A slider for a fuel sender, said slider being capable of moving on a conductor in conjunction with a float capable of moving in accordance with a liquid level, said slider comprising a contact material which comprises 10 to 25 mass % of nickel and a balance being palladium, which contact material has been formed by melt casting.

2. A fuel sender having the slider defined in claim 1.

3. A fuel sender for detecting a liquid level in a fuel tank which comprises: a substrate, a conductor on the substrate, and a resistor on the substrate, which resistor is electrically connected to the conductor, a slider electrically connected to the conductor and which slider is capable of moving on the conductor, the slider being connected to an arm, which arm is connected to a float, which float is adapted to rise and fall in accordance with a liquid level when positioned in a fuel tank, which slider changes a value of the resistor in response to a movement of the arm, the slider comprising a contact material which comprises 10 to 25 mass % of nickel and a balance being palladium, which contact material has been formed by melt casting.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a diagram illustrating a configuration of a general fuel sender.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(2) An embodiment of the present invention will be described based on Examples described below. In this embodiment, palladium-nickel alloys having various amounts of nickel added were manufactured and, for test pieces formed by the processing of the alloy into the dimension equivalent to the slider, hardness and corrosion resistance were evaluated.

(3) The palladium-nickel alloy was produced by the melting casting process. The respective base metals having high purity were mixed and melt in a melting furnace to produce an alloy ingot. Then, test pieces (20 mm length, 3 mm width, 0.3 mm thickness) were produced by forging processing and rolling processing. In this processing, heat treatment was performed at 750° C. in nitrogen flow for every processing of 40 to 60%. The processing rate on completion of the processing after the last heat treatment was set to 45%. Then, hardness measurement and a corrosion test were performed for this test piece.

(4) Vickers hardness measurement (200 gf load) was performed as a hardness measurement of the alloy. Moreover, for a corrosion test, a Au probe was contacted with the surface of the following samples (10 gf load), and contact resistance was measured by an AC four-probe method (current value 10 mA): a sample formed by immersion of a test piece in a formic acid solution (0.1 mass %) and an acetic acid solution (0.1 mass %)at 58° C. for 300 hours; and a sample formed by exposure of a test piece to hydrogen sulfide gas (temperature 40° C., humidity 80%) in a concentration of 12.5 ppm (remainder: air) for 24 hours.

(5) In each of the above-mentioned evaluation tests, with consideration for use conditions of the slider of the fuel sender, the following acceptance criteria were defined: hardness was 150 Hv or more and corrosion resistance (contact resistance) was less than 20 mΩ in any environment. In this evaluation test, a copper-nickel alloy as a conventional technology was also evaluated. This test result is shown in Table 1.

(6) TABLE-US-00001 TABLE 1 Test result Contact resistance (mΩ) Alloy composition Hard- For- Ace- (wt. %) ness mic tic H.sub.2S Pd Ni Cu Zn (Hv) acid acid gas Example 1 90 10 — — 210 7.3 6.4 6.5 Example 2 85 15 — — 240 7.6 9.8 7.1 Example 3 80 20 — — 255 8.7 11.3 11.4 Example 4 75 25 — — 300 10.3 14.0 12.7 Comparative 100 — — — 80 6.8 5.0 5.8 Example 1 Comparative 95 5 — — 145 6.5 5.3 6.0 Example 2 Comparative 70 30 — — 320 13.7 22.5 15.1 Example 3 Conventional — 8 72 20 230 ∞ ∞ 91.0 example

(7) In view of Table 1, while the addition of nickel to palladium raises hardness, there is a tendency of decreasing corrosion resistance. Thus, when the above-mentioned acceptance criteria for the slider of fuel sender is taken into consideration, it is deemed that a suitable nickel content is 10 to 25 mass %.

INDUSTRIAL APPLICABILITY

(8) The contact material composed of a palladium-nickel alloy according to the present invention is excellent in corrosion resistance and durability, and is optimal for a composition material of the slider of the fuel sender. Moreover, the contact material according to the present is useful also in the light of material cost. The slider of the fuel sender of the present invention is useful for vehicles, such as FFV, using composite fuel of alcohol and the like, and can contribute to the response to recent spread of the vehicles in the setting of energy problems.