Spark plug electrode material and spark plug and method for manufacturing the spark plug electrode material and an electrode for the spark plug

Abstract

A spark plug electrode material containing a) 0.7 to 1.3% silicon by weight, b) 0.5 to 1.0% copper by weight, and c) nickel as the balance.

Claims

1. A spark plug electrode material, comprising: 0.7 to 1.3% silicon by weight; 0.5 to 1.0% copper by weight; 0.07 to 0.13% yttrium by weight; and nickel as the balance.

2. The spark plug electrode material of claim 1, wherein the level of silicon is 0.9 to 1.1%, the level of copper is 0.6 to 0.85%, and the level of nickel is approximately 97.5 to 98.5% by weight.

3. The spark plug electrode material of claim 1, wherein the electrode material is free of aluminum, aluminum compounds, and intermetallic phases.

4. The spark plug electrode material of claim 1, wherein the level of metallic impurities amounts to, in total, less than 0.15% by weight.

5. The spark plug electrode material of claim 1, wherein the level of iron, chromium, and titanium is less than 0.05% by weight.

6. The spark plug electrode material of claim 1, wherein the level of sulfur, sulfur compounds, carbon, and carbon compounds is less than 0.01% by weight.

7. The spark plug electrode material of claim 1, wherein the level of oxygen is less than 0.003% by weight.

8. The spark plug electrode material of claim 1, including: a) 98.15% nickel by weight, b) 1% silicon by weight, c) 0.75% copper by weight, and d) 0.1% yttrium by weight.

9. The spark plug electrode material of claim 1, including: a) 0.7 to 1.3% silicon by weight, b) 0.5 to 1.0% copper by weight, c) 0.07 to 0.13% yttrium by weight, d) less than 0.003% oxygen by weight, e) 0.001% sulfur by weight, f) 0.003% carbon by weight, g) balance: nickel, the level of metallic impurities amounting to, in total, less than 0.1% by weight.

10. The spark plug electrode material of claim 1, wherein the level of silicon is 1% by weight, and/or the level of copper is 0.75% by weight, and the level of nickel is approximately 97.5 to 98.5% by weight.

11. The spark plug electrode material of claim 1, wherein the level of iron chromium, and titanium is less than 0.01% by weight.

12. The spark plug electrode material of claim 1, wherein the level of sulfur, sulfur compounds, carbon, and carbon compounds is less than 0.005% by weight.

13. The spark plug electrode material of claim 1, wherein the level of oxygen is less than 0.003% by weight.

14. The spark plug electrode material of claim 1, including: a) 1% silicon by weight, b) 0.75% copper by weight, c) 0.1% yttrium by weight, d) less than 0.002% oxygen by weight, e) 0.001% sulfur by weight, f) 0.003% carbon by weight, g) balance: nickel, the level of metallic impurities amounting to, in total, less than 0.1% by weight.

15. The spark plug electrode material of claim 1, wherein it further contains 0.10% yttrium by weight.

16. The spark plug electrode material of claim 1, wherein the level of sulfur, sulfur compounds, carbon, and carbon compounds is less than 0.001% by weight.

17. A spark plug, comprising: an electrode made of a spark plug electrode material, including 0.7 to 1.3% silicon by weight, 0.5 to 1.0% copper by weight, 0.09 to 0.11% yttrium by weight, and nickel as the balance.

18. The spark plug of claim 17, wherein the electrode is a center electrode a copper core.

19. The spark plug of claim 17, wherein the electrode is a center electrode without a copper core.

20. The spark plug of claim 17, wherein the electrode is a ground electrode with a copper core.

21. The spark plug of claim 17, wherein the electrode is a ground electrode without a copper core.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a graph, which shows the erosion per ignition spark of the spark plug electrode material of the present invention in comparison with a conventional spark plug electrode material.

(2) FIG. 2 shows a spark plug according to the present invention, including a ground electrode and a center electrode, the center electrode taking the form of a two-material electrode, and the ground electrode taking the form of a one-material electrode.

(3) FIG. 3 shows a spark plug according to the present invention, including a ground electrode and a center electrode, the center electrode taking the form of a two-material electrode, and the ground electrode also taking the form of a two-material electrode.

DETAILED DESCRIPTION

(4) FIG. 1 is a graph, which shows the erosion in μm.sup.3/spark, including standard deviation, of the spark plug electrode material A of the present invention in comparison with a conventional spark plug electrode material B, as described below.

(5) The spark plug electrode material A of the present invention had the following composition: a) 1% silicon by weight, b) 0.75% copper by weight, c) 0.1% yttrium by weight, d) 0.002% oxygen by weight, e) 0.001% sulfur by weight, f) 0.003% carbon by weight,
where the balance of the material was nickel, and the level of metallic impurities amounted to, in total, less than 0.1% by weight.

(6) The conventional spark plug electrode material B had the following composition: a) 1% silicon by weight, b) 1% aluminum by weight, c) 0.2% yttrium by weight,
where the balance of the material was nickel. The specific levels of the elements of the spark plug electrode materials were determined using ICP.

(7) The two materials A and B were subjected to a spark erosion test in air at an electrode temperature of 900° C., a pressure of 7 bar, and with the aid of ignition coils having a starting spark current of 90 mA. The graph clearly shows the elevated erosion per spark of app. 25 μm.sup.3/spark of the conventional, aluminum-containing electrode material B, in comparison with the app. 18 μm.sup.3/spark of the optimized spark plug electrode material A of the present invention. In this context, the markedly lower spark erosion of the electrode material A of the present invention may be attributed to the formation of a homogeneous, relatively thin oxide layer having excellent thermal conductivity and low electrical resistance, and thus, high electrical conductivity.

(8) FIG. 2 shows a spark plug 1 according to the present invention, having a center electrode 2 and a ground electrode 3; both center electrode 2 and ground electrode 3 being made of the spark plug electrode material of the present invention. In this context, center electrode 2 takes the form of a two-material electrode, and ground electrode 3 takes the form of a one-material electrode.

(9) FIG. 3 shows a spark plug 1 according to the present invention, having a center electrode 2 and a ground electrode 3, center electrode 2 and also ground electrode 3 taking the form of a two-material electrode, including an electrode cover 5 made of the spark plug electrode material of the present invention and an electrode core 4 made of a core material, which may be copper.

(10) Therefore, the present invention provides a spark plug electrode material for manufacturing a spark plug electrode or, in general, a spark plug; due to the formation of an oxide layer during, in particular, normal use, the spark plug electrode material being distinguished by low spark erosion and excellent corrosion resistance with minimized production costs and sufficient thermodynamic and mechanical stability.