A kind of iridium-nickel-iron alloy and its preparation method and application

A nickel-iron alloy, iridium-rhodium alloy technology, applied in spark plugs, circuits, electrical components, etc., can solve the problems of easy falling off of the alloy, limited application, high price, and achieve the effect of solving unstable welding quality and solving poor welding quality.

Active Publication Date: 2020-02-07
HUNAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the thermal expansion coefficient of iridium and iridium-rhodium alloys is small, and the thermal expansion coefficient of nickel-based alloys is large. After welding, the alternating action of cold and heat during use can easily cause iridium and iridium-rhodium alloys to fall off and fail, especially larger-sized iridium and iridium-rhodium alloys. Rhodium alloys fall off more easily
In addition, the high prices of iridium and iridium-rhodium alloys also limit the application of iridium and iridium-rhodium alloys as spark plug electrode materials

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Taking the preparation of an iridium-nickel-iron alloy with a component content of 60% nickel, 30% iridium and 10% iron as an example, the steps are as follows:

[0033] (1) Manufacture and assembly mold: Prepare a copper mold as a forming mold for iridium-nickel-iron alloy. The diameter of the copper mold cavity is 25 mm and the length is 65 mm. The copper mold is assembled in a vacuum electric arc furnace;

[0034] (2) Loading samples: Turn on the vacuum electric arc furnace, put 30g of high-purity iridium (>99.9 wt.%), 65g of high-purity nickel (>99.9wt.%) and 5g of high-purity iron (>99.9 wt.%) into the vacuum electric arc furnace in the crucible;

[0035] (3) Vacuuming: Open the vacuum valve and vacuumize until the vacuum degree is 2.5×10 -3 MPa, then tighten the vacuum valve;

[0036] (4) Inflating: Pour argon into the sample chamber of the vacuum electric arc furnace until the vacuum degree is 0.55MPa;

[0037] (5) Repeat steps 2 to 4 4 times;

[0038] (6) Va...

Embodiment 2

[0045] The difference between this embodiment and Example 1 is that the composition (mass percentage) of the iridium-nickel-iron alloy is 30% nickel, 65% iridium, and 5% iron, and the vacuum degree in step 3 is 5.5×10 -3 MPa, pour in argon gas until the vacuum degree is 0.8MPa, repeat the operation from step 2 to step 4 twice, continue to heat up to 2300°C after the metal is melted, keep warm for 0.45min, the output current of magnetic stirring is 20A, and the diameter of molten metal pouring is 50mm, length of 25 mm copper mold; iridium-nickel-iron alloy cylinder into the tube furnace, vacuum to 1.2 × 10 -1 MPa, fill with hydrogen to 0.55MPa, heat up to 1350°C, keep warm for 25 minutes, resistance welding of iridium-nickel-iron alloy and φ0.8mm iridium-rhodium 10, welding time 1.5s, current density 90A / mm 2 , pressure 35MPa. Resistance welding of iridium-nickel-iron alloy and Inconel 600 alloy, welding time 1.8s, current density 90A / mm 2 , pressure 25MPa.

[0046] The obta...

Embodiment 3

[0048] The difference between this embodiment and embodiment 1 is that the component content in the iridium-nickel-iron alloy is 50% nickel, 40% iridium, 10% iron, and the vacuum degree is 4.0×10 -3 MPa, pour in argon gas until the vacuum degree is 0.70MPa, continue to heat up to 2200°C after melting the metal, keep it warm for 0.85min, and the output current of magnetic stirring is 30A; put the iridium-nickel-iron alloy cylinder into the tube furnace, and evacuate to 1.5× 10 -1 MPa, fill with hydrogen to 0.60MPa, heat up to 1250°C, hold for 50 minutes, resistance welding of iridium-nickel-iron alloy and φ3.8mm iridium gold, welding time 1.8s, current density 110A / mm 2 , pressure 35MPa.

[0049] The obtained iridium-rhodium alloy electrode undergoes cold and heat fatigue at room temperature to 900°C for 100 times, and the weld crack is less than 1 / 6 of the cross-sectional size of the weld.

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PUM

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Abstract

The invention discloses an iridium-nickel-iron alloy and a preparation method thereof. The preparation method comprises the following steps: taking iron, nickel and iridium and putting into a vacuum condition; under a vacuum state, heating metal to obtain alloy liquid; casting the alloy liquid into a copper die and carrying out casting to obtain an alloy casting ingot; carrying out homogenizationtreatment on the alloy casting ingot to obtain the iridium-nickel-iron alloy, wherein the obtained iridium-nickel-iron alloy is prepared from the following components in percentage by mass: 30 to 65 percent of the iridium, 30 to 60 percent of the nickel and 5 to 10 percent of the iron. According to the preparation method provided by the invention, firstly, a vacuum furnace is used for smelting andthen a water-cooling copper crucible is used for casting; then homogenization treatment is carried out and the generated iridium-nickel-iron alloy is used as a middle-layer welding material, so thatthe welding of the iridium, an iridium-rhodium alloy and an Inconel 600 alloy is realized; and 30 to 65 percent of a noble metal material is saved and the problem that the welding quality is not stable because noble metal and a nickel-based alloy have great thermal expansion coefficient difference is solved.

Description

technical field [0001] The invention relates to the technical field of electrode materials, in particular to an iridium-nickel-iron alloy and its preparation method and application. Background technique [0002] All gasoline engines have spark plugs, one per cylinder, and some high-speed gasoline engines have two spark plugs per cylinder. Although the spark plug is small, it affects the engine's starting ability, fuel consumption and exhaust emission level. If the engine is the heart of the car, then the spark plug is the "pacemaker" of the "heart". [0003] The function of the spark plug is to introduce the high-voltage electricity (above 10,000 V) generated by the ignition coil into the engine cylinder, and generate sparks between the electrodes of the spark plug to ignite the air-fuel mixture. Among them, the working environment of the spark plug electrode as the discharge part is extremely harsh. Taking the spark plug of an ordinary four-stroke gasoline engine as an ex...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C30/00C22C5/04C22C19/03C22C1/02H01T13/39
CPCC22C1/02C22C1/023C22C5/04C22C19/03C22C30/00H01T13/39
Inventor 王振生
Owner HUNAN UNIV OF SCI & TECH
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