JPH03111534A - Electrode material for spark plug - Google Patents

Abstract

PURPOSE:To manufacture the electrode material for a spark plug excellent in durability by adding specified amounts of Ta, etc., to a Cr-base alloy contg. a specified amt. of Ni. CONSTITUTION:An electrode material for a spark plug contg., by weight, 10 to 45% Ni, furthermore contg. total 0.3 to 3% of one or more kinds among Ta, B, Be, V, La, Al, Ce, Ti and Zr and the balance Cr with inevitable impurities is prepd. In this way, the electrode material constituted of the Cr-base alloy excellent in oxidation resistance, consumption resistance, workability and weld cracking resistance can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a spark plug electrode material used for the tip of an electrode that forms a spark gap in a spark plug for an internal combustion engine.

[Conventional technology]

The tip of the electrode that forms the spark gap of a spark plug for an internal combustion engine is processed into a desired shape, then further sized or coined, and then attached to the tip of the electrode by caulking press or resistance welding. Therefore, the spark plug electrode material used for the tip of the electrode generally does not crack due to caulking or resistance welding, does not oxidize even when exposed to extremely high temperatures, and is resistant to wear due to sparks. It was made of a material that exhibits high resistance to . As a material for overcasting,
It is well known that Pt or pt gold alloys are the most reliable. However, Pt or pt-gold alloys are extremely expensive, and using them in large quantities industrially poses a cost problem.Currently, they are only used in some special models, and most of them are made of Cr. ~6% (weight%, less than %
% by weight) is used.

Although this alloy is somewhat satisfactory as a material for the tip of the electrode of a spark plug, it is not sufficient in terms of resistance to spark wear. Therefore, an electrode material for a spark plug made of an N1 alloy with an increased Cr content of 10 to 50% has been proposed (see Japanese Patent Laid-Open No. 58-59579).

[Problem to be solved by the invention]

The spark plug electrode material made of the above N1 alloy is C
The higher the r content, the better the oxidation resistance even when exposed to high temperatures in a harsh oxidizing atmosphere, and the better the abrasion resistance against sparks. However, workability deteriorates, and cracks also occur during resistance welding. Therefore, although Cr alloys with a Cr content of more than 50% (i.e., Cr-based alloys containing 10 to 45% NI) have excellent oxidation resistance at high temperatures in harsh oxidizing atmospheres and wear resistance against sparks, It had poor workability and cracked during resistance welding, so it was not used as an electrode material for spark plugs.

[Means to solve the problem]

Therefore, the present inventors proposed that it would be possible to impart workability to a Cr-based alloy containing 10 to 45% Ni, which has excellent oxidation resistance at high temperatures in a harsh oxidizing atmosphere and wear resistance against sparks. As a result of conducting research based on the prediction that it could be used as an excellent electrode material for spark plugs, we found that Ta and B were added to a Cr-based alloy containing 10 to 45% Ni.

One of Be, V, La, All, Ce, Ti, Zr
When one or more species are added in a total amount of 0.3 to 3%, the Cr-based material has excellent oxidation resistance at high temperatures in a harsh oxidizing atmosphere and wear resistance against sparks, as well as excellent workability and weld cracking resistance. An alloy can be obtained, and this C
They have found that using r-based alloys as electrode materials for spark plugs has excellent effects.

This invention was made based on this knowledge, and contains Nl: 10 to 45%, and further contains Ta, B, Be, V, La, Al, Ce, and TI.

The spark plug electrode material is characterized by containing one or more Zr in a total amount of 0.3 to 3%, with the balance being Cr and unavoidable impurities.

Next, the reason why the component composition of the spark plug electrode material of the present invention is limited as described above will be explained.

(a) Nl The N1 component is an element that improves tensile strength, but if its content is less than 10%, the desired tensile strength cannot be obtained, while if its content exceeds 45%, there will be problems with heat resistance. This is not preferable because it causes

Therefore, the N1 content was set at 10-45%.

(b) Ta If less than 0.3% of Ta is added, the desired performance cannot be obtained; on the other hand, if Ta is added in an amount of more than 3%, an even better effect cannot be obtained, and on the contrary, it becomes a negative factor in terms of strength. This is not desirable.

Therefore, the Ta content was determined to be 0.3 to 3%.

(c) B Even if the B component is contained in an amount less than 0.3%, the desired effect cannot be obtained. On the other hand, if its content exceeds 3%, it becomes a negative factor in terms of strength. Therefore, the B content is 0
．． It was set at 3-3%.

(d) Be If the Be component is contained in an amount less than 0.3%, the desired effect will not be obtained, whereas if the content exceeds 3%, it will be a negative factor in terms of strength, which is not preferable.

Therefore, the Be content was set at 0.3 to 3%.

(e) The desired effect cannot be obtained even if the component V (V) is contained in an amount of less than 0.3%; on the other hand, even if its content exceeds 3%,
The effect of increasing the amount added becomes less, which is economically unfavorable. Therefore, V: was set at 0.3 to 3%.

(f) La The desired effect cannot be obtained even if the La content is less than 0.3%, and on the other hand, no increase in effect can be expected even if the content exceeds 3%, so La: It was set at 0.3 to 3%.

(g) l! If the AI acid component is less than 0.3%, the desired effect cannot be obtained,
On the other hand, if the Ag content exceeds 3%, the desired effect will not be improved and instead the brittleness will increase, so the Ag content was set at 0.3 to 3%.

(h) Ce If the Ce component is contained less than 0.3%, the desired effect will not be obtained; on the other hand, if the content exceeds 3%, no effect will be obtained, especially by increasing the amount added. By the way, Ce:
It was set at 0.3 to 3%.

(1) If the Tt TI acid component is less than 1.3%, the effect will not be clearly apparent, and on the other hand, if the content exceeds 3%, the effect will not be improved by increasing the amount added. Therefore, the Ti content is 0.3-3
%.

(j) Zr Z "If the component is less than 0.3%, the desired effect cannot be obtained,
On the other hand, even if the content exceeds 3%, no additional effect beyond the intended purpose can be obtained. Therefore, the Zr content is 0.3-3
%.

〔Example〕

The raw material powders are: Cr powder with an average particle size of lO-, Ni powder with an average particle size of 51, Ta powder with an average particle size of +10 m, Cr-B reaction powder with an average particle size of 10 μs, and average particle size: 1
Be powder with an average particle size of 0IA, V powder with an average particle size of 10, Ni-Ag powder with an average particle size of 15, Ce powder with an average particle size of 1O-, TI powder with an average particle size of 15, average particle size :15℃m Zr powder, These metal powders were blended to have the component composition shown in the Examples and Comparative Examples in Table 1, mixed in a ball mill, and the obtained powder was heated to 6t/C. Press-molded at a pressure of - to form a green compact with a diameter of 12+ om x thickness of 12 mm, and place these green compacts in hydrogen gas with a dew point of -20°C at a temperature of:
Sintering was carried out at a predetermined temperature of 1200-1400°C for 60 minutes. The elongation and tensile strength of the obtained sintered body were measured and the results are shown in Table 1. Next, the sintered body was sized at a pressure of 7t/c-, and the presence or absence of cracks during this sizing was examined, and the results were reported in the first section.
Shown in the table.

Furthermore, the sized sintered body that did not crack during the above sizing was resistance welded to the tip of the electrode that forms the spark gap of the spark plug, and the presence or absence of weld cracks during the above resistance welding was examined. The results are shown in Table 1.

The spark plug electrode obtained by resistance welding the tip of the electrode without causing sizing cracks or welding cracks was heated in a pressure vessel held at a pressure of 5 kg/cd and a temperature of 250°C with spark energy: 50+1jOule.

A spark consumption test was carried out at 2000 sparks/min and maintained for 100 hours, and the increase in the spark gap of the spark plug electrode was measured to evaluate the spark consumption resistance.The results are shown in Table 1. .

Furthermore, for comparison, a spark consumption test was conducted on a conventional spark plug electrode under exactly the same conditions, and the results are also shown in Table 1.

From the results in Table 1, Ni: 10-45%, Ta, B.

A spark plug electrode material containing a total of 0.3 to 3% by weight of one or more of Be, V, La, AΩ, Ce, TI, and Zr, with the remainder being Cr and unavoidable impurities, has been conventionally used. It has superior spark abrasion resistance compared to the spark plug electrode material of 2007, and there are no cracks due to sizing or welding, which indicates that no cracks occur during the process of processing into spark plug electrodes.

〔Effect of the invention〕

Spark plugs manufactured using the spark plug electrode material of this invention have superior durability compared to conventional products, and the occurrence of defective products during the manufacturing process is as low as conventional products, providing excellent industrial effects. It is something.

Claims (10)

[Claims] (1) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Ta: 0.3 to 3% by weight, and the balance consists of Cr and inevitable impurities. (2) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, B: 0.3 to 3% by weight, and the balance consists of Cr and inevitable impurities. (3) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Be: 0.3 to 3% by weight, and the balance consists of Cr and inevitable impurities. (4) An electrode material for a spark plug, characterized in that it contains 10 to 45% by weight of Ni, 0.3 to 3% by weight of V, and the remainder consists of Cr and inevitable impurities. (5) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, La: 0.3 to 3% by weight, and the remainder consists of Cr and inevitable impurities. (6) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Al: 0.3 to 3% by weight, and the remainder consists of Cr and unavoidable impurities. (7) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Ce: 0.3 to 3% by weight, and the remainder consists of Cr and inevitable impurities. (8) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Ti: 0.3 to 3% by weight, and the remainder consists of Cr and inevitable impurities. (9) An electrode material for a spark plug, characterized in that it contains Ni: 10 to 45% by weight, Zr: 0.3 to 3% by weight, and the remainder consists of Cr and inevitable impurities. (10) Contains Ni: 10 to 45% by weight, and further contains a total of 0.3 to 3% by weight of two or more of Ta, B, Be, V, La, Al, Ce, Tl, and Zr. And the rest:
An electrode material for a spark plug characterized by comprising Cr and inevitable impurities.