EP1090155A1 - Spark plug electrode alloy - Google Patents
Spark plug electrode alloyInfo
- Publication number
- EP1090155A1 EP1090155A1 EP99930453A EP99930453A EP1090155A1 EP 1090155 A1 EP1090155 A1 EP 1090155A1 EP 99930453 A EP99930453 A EP 99930453A EP 99930453 A EP99930453 A EP 99930453A EP 1090155 A1 EP1090155 A1 EP 1090155A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- less
- aluminum
- nickel
- alloy
- silicon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 73
- 239000000956 alloy Substances 0.000 title claims abstract description 73
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 108
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 54
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 54
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 53
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 51
- 239000010936 titanium Substances 0.000 claims abstract description 33
- 239000011651 chromium Substances 0.000 claims abstract description 32
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 31
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 31
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 30
- 239000010703 silicon Substances 0.000 claims abstract description 29
- 239000011572 manganese Substances 0.000 claims abstract description 28
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 27
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims abstract description 26
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 26
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000012535 impurity Substances 0.000 claims abstract description 25
- 229910052742 iron Inorganic materials 0.000 claims abstract description 25
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000010304 firing Methods 0.000 claims description 11
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 13
- 229910000943 NiAl Inorganic materials 0.000 description 11
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 description 11
- 239000000203 mixture Substances 0.000 description 7
- 238000005260 corrosion Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 6
- 238000002485 combustion reaction Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 229910052814 silicon oxide Inorganic materials 0.000 description 5
- 238000005482 strain hardening Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000007772 electrode material Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000005486 sulfidation Methods 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- -1 carbon Chemical compound 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 1
- 238000009760 electrical discharge machining Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical class [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- CADICXFYUNYKGD-UHFFFAOYSA-N sulfanylidenemanganese Chemical compound [Mn]=S CADICXFYUNYKGD-UHFFFAOYSA-N 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/39—Selection of materials for electrodes
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
- C22C19/058—Alloys based on nickel or cobalt based on nickel with chromium without Mo and W
Definitions
- a spark plug In general, a spark plug generates a spark in a gap between a ground electrode and a firing electrode of the spark plug.
- the quality of the spark depends on the material composition of the electrodes and other factors. Because of the extreme conditions in the atmosphere of a cylinder of an operating internal combustion engine, the material must have high strength at elevated temperatures, high melting loss resistance, corrosion resistance, and spark erosion resistance, and also must maintain thermal and electrical conductivity at high temperatures. For instance, if the electrode material has poor corrosion resistance, the electrode will corrode in the cylinder until there is little material left and the spark plug ceases to function.
- Conventional spark plug electrodes may include a nickel-based alloy in which elements are selectively included to improve properties of the electrode.
- a known nickel-based alloy identified as Champion Alloy 522, includes nickel (Ni), titanium (Ti), silicon (Si), manganese (Mn), chromium (Cr), iron (Fe), zirconium (Zr), carbon (C), and a small quantity of unavoidable impurities. The proportion of each element contributes to the properties of the alloy.
- the known alloy includes 94.5-95.5% Ni, 0.20-0.30% Ti, 0.35-0.55% Si, 1.80- 2.10% Mn, 1.65-1.90% Cr, 0.10-0.20% Zr, and a maximum of 0.50% Fe, 0.05% C and 0.25% other impurities.
- a nickel, aluminum-based electrode alloy includes aluminum, silicon, chromium, manganese, iron, carbon, titanium, zirconium, and impurities, and the remainder nickel.
- Aluminum is present in the NiAl alloy in a preferred range of 0.75 to 2.2 weight percent. A more preferred range is 1.5 to 2.1 weight percent. An even more preferred amount of aluminum in the alloy is about 1.8 weight percent. Silicon is present in the alloy in a preferred range of 1.1 to 1.75 weight percent. A more preferred amount of silicon in the alloy is in the range of 1.1 to 1.3 weight percent. An even more preferred amount of silicon in the alloy is about 1.2 weight percent. Chromium is present in the alloy in a preferred range of 1.45 to 1.9 weight percent. A more preferred range is 1.45 to 1.8 weight percent. An even more preferred amount of chromium in the alloy is about 1.6 weight percent. Manganese is present in the alloy in a preferred range of 0.3 to 0.6 weight percent. A more preferred range is 0.3 to 0.5 weight percent. An even more preferred amount of manganese in the alloy is about 0.4 weight percent.
- Iron occurs naturally in nickel and is present in a preferred amount less than 0.5 weight percent. A more preferred amount is less than 0.2 weight percent. An even more preferred amount of iron in the alloy is less than 0.1 weight percent. Titanium, zirconium and impurities, such as carbon, are present in the NiAl alloy in an amount preferably less than 0.2 weight percent. A more preferred amount is less than 0.1 weight percent zirconium and less than 0.02 weight percent titanium. An even more preferred amount is less than 0.05 weight percent zirconium and less than 0.01 weight percent titanium. An even more preferred amount is less than 0.005 weight percent titanium. Referring specifically to carbon as an impurity, it should be present at 0.05 weight percent or less. Nickel comprises the remainder of the composition of the alloy.
- the NiAl alloy When used as the electrode material in a spark plug, the NiAl alloy has the considerable advantage of forming a durable oxide film or scale on the electrode that restricts harmful oxidation and sulfidation to reduce corrosion of the electrode. The alloy also improves the performance of the electrode by reducing gap growth.
- Fig. 1 is a front view of a spark plug.
- a spark plug 100 includes an insulator 105, an outer shell 110, a ground electrode 115 attached to outer shell 110, and a firing electrode 120 adjacent to ground electrode 115.
- a spark gap 125 is defined between ground electrode 115 and firing electrode 120.
- Ground electrode 115 and firing electrode 120 are made of a nickel, aluminum alloy (NiAl alloy) that includes nickel (Ni), aluminum (Al), titanium (Ti), silicon (Si), manganese (Mn), chromium (Cr), iron (Fe), and zirconium (Zr). Each element contributes to the properties of the NiAl alloy.
- Aluminum is present in the NiAl alloy in a preferred range of 0.75 to 2.2 weight percent. A more preferred range is 1.5 to 2.1 weight percent. An even more preferred amount of aluminum in the alloy is about 1.8 weight percent.
- Aluminum is added to the NiAl alloy primarily because it forms a durable and stable oxide film in the form of aluminum oxide (Al 2 O 3 ). On an atomic scale, the alloy is made of grains ordered in a grain arrangement. The oxide film is formed in the grain boundaries, where the alloy is likely to be attacked in the processes of oxidation and sulfidation during combustion. These processes corrode the electrodes by causing grains to drop out of the grain boundary. The formation of a durable aluminum oxide film restricts harmful oxidation and sulfidation and, thus, reduces corrosion.
- Aluminum also contributes to faster work hardening than would occur during the normal plastic deformation associated with cold working of the alloy. During cold working, larger grains are broken into smaller grains. Because of energy level differences, the aluminum atoms migrate to the grain boundaries. The aluminum atoms are smaller than the nickel atoms they replace, which makes the material harder to work further and thereby improves work hardening. After cold working, an alloy of nickel and aluminum generally is harder than the alloy without aluminum.
- Silicon is present in the alloy in a preferred range of 1.1 to 1.75 weight percent. A more preferred amount of silicon in the alloy is in the range of 1.1 to 1.3 weight percent. An even more preferred amount of silicon in the alloy is about 1.2 weight percent. Silicon forms a durable oxide film similar to the film formed by aluminum. In particular, the silicon undergoes a reaction with oxygen attacking the alloy in the grain boundaries. The reaction produces the oxide, silicon oxide (SiO 2 ), which, in turn, creates a compressive force on the surface to form a protective oxide scale.
- Chromium is present in the alloy in a preferred range of 1.45 to 1.9 weight percent. A more preferred range is 1.45 to 1.8 weight percent. An even more preferred amount of chromium in the alloy is about 1.6 weight percent. Chromium is added because it reacts with oxygen to form a durable chromium oxide (Cr 2 O 3 ) scale with properties similar to the aluminum and silicon oxides. However, the weight percentage of chromium is restricted because its presence reduces thermal and electrical conductivity, both of which must be maintained to ensure performance of the spark plug.
- Manganese is present in the alloy in a preferred range of 0.3 to 0.6 weight percent. A more preferred range is 0.3 to 0.5 weight percent. An even more preferred amount of manganese in the alloy is about 0.4 weight percent.
- Manganese reacts with sulfur present in combustion gases in the combustion chamber more than it reacts with oxygen due to sulfur' s higher level of energy. The reaction produces manganese sulfide (MnS) as a film on the surface of the electrode. This film generates a compressive force on the surface similar to the compressive force produced by silicon oxide. The film and compressive force block additional sulfur and oxygen from passing through to the alloy below.
- MnS manganese sulfide
- Iron occurs naturally in nickel and is present in a preferred amount less than 0.5 weight percent. A more preferred amount is less than 0.2 weight percent. An even more preferred amount of iron in the alloy is less than 0.1 weight percent. Like chromium, the weight percentage of iron is limited because it affects thermal and electrical conductivity.
- Titanium and zirconium are present in the alloy because they occur naturally in nickel as trace elements. Together with impurities, such as carbon, they are present in the NiAl alloy in an amount preferably less than 0.2 weight percent. A more preferred amount is less than 0.1 weight percent zirconium and less than 0.02 weight percent titanium. An even more preferred amount is less than 0.05 weight percent zirconium and less than 0.01 weight percent titanium. An even more preferred amount is less than 0.005 weight percent titanium. Referring specifically to carbon as an impurity, it should be present at a maximum of 0.05 weight percent. Titanium forms a durable oxide film that reduces corrosion. However, titanium is more expensive and more difficult to process than aluminum. Zirconium also forms a durable oxide film that reduces corrosion.
- Nickel comprises the remainder of the composition of the alloy. Nickel has the beneficial property of high temperature integrity.
- the percentages of the elements in the alloy are based on atomic percentages.
- Table 1 illustrates the weight percentages and atomic percentage of one composition of the alloy.
- the composition was developed based on the atomic percentages of aluminum, silicon, and chromium necessary to form a durable oxide scale with similar proportions of each oxide. For instance, to have similar proportions of silicon oxide, aluminum oxide, and chromium oxide, the atomic percentages of the elements are one silicon atom for every two aluminum atoms and chromium atoms. From this ratio, the atomic percentages and weight percentages can be calculated. Constraints on the compositions generated by this method are the availability of alloys designed according to this method and manufacturability of the alloy into electrodes.
- ground and firing electrodes were fabricated from the alloy using a composition specified to be within the weight percentage ranges described above. Spark plugs then were fabricated using the electrodes and the spark plugs mounted in combustion engines. Ground and firing electrodes also were made using Champion Alloy 522, and finished spark plugs were installed in internal combustion engines. The engines were operated using leaded fuel . Periodically, the spark gaps were examined for spark gap growth (i.e., the increase in gap distance between the ground and firing electrodes caused by erosion of the electrodes) . After 180 hours of operation, the ground electrode fabricated from Champion Alloy 522 had eroded almost completely. After 200 hours of operation, the ground electrode fabricated from the NiAl alloy showed little erosion of either the ground or firing electrode. An analysis of the results showed a 30-40% increase in performance of the electrode material as measured by reduced gap growth. Results also indicate that the NiAl alloy electrodes provide increased performance when used to combust unleaded fuel .
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- Engineering & Computer Science (AREA)
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Spark Plugs (AREA)
Abstract
A nickel, aluminum-based electrode alloy comprising, by weight: (i) between 0.75 and 2.2 % aluminum; (ii) between 1.1 and 1.75 % silicon; (iii) between 1.45 and 1.9 % chromium; (iv) between 0.6 % manganese; (v) between 0.5 % iron; (vi) between 0.05 % carbon; (vii) between 0.2 % of the combination of titanium, zirconium, and impurities; and (viii) the remainder nickel. The alloy is used for electrodes in spark plugs.
Description
SPARK PLUG ELECTRODE ALLOY
BACKGROUND
In general, a spark plug generates a spark in a gap between a ground electrode and a firing electrode of the spark plug. The quality of the spark depends on the material composition of the electrodes and other factors. Because of the extreme conditions in the atmosphere of a cylinder of an operating internal combustion engine, the material must have high strength at elevated temperatures, high melting loss resistance, corrosion resistance, and spark erosion resistance, and also must maintain thermal and electrical conductivity at high temperatures. For instance, if the electrode material has poor corrosion resistance, the electrode will corrode in the cylinder until there is little material left and the spark plug ceases to function.
Conventional spark plug electrodes may include a nickel-based alloy in which elements are selectively included to improve properties of the electrode. For example, a known nickel-based alloy, identified as Champion Alloy 522, includes nickel (Ni), titanium (Ti), silicon (Si), manganese (Mn), chromium (Cr), iron (Fe), zirconium (Zr), carbon (C), and a small quantity of unavoidable impurities. The proportion of each element contributes to the properties of the alloy. Specifically, the known alloy includes 94.5-95.5% Ni, 0.20-0.30% Ti, 0.35-0.55% Si, 1.80- 2.10% Mn, 1.65-1.90% Cr, 0.10-0.20% Zr, and a maximum of 0.50% Fe, 0.05% C and 0.25% other impurities.
SUMMARY
In one general aspect, a nickel, aluminum-based electrode alloy includes aluminum, silicon, chromium, manganese, iron, carbon, titanium, zirconium, and impurities, and the remainder nickel.
Aluminum is present in the NiAl alloy in a preferred range of 0.75 to 2.2 weight percent. A more preferred range is 1.5 to 2.1 weight percent. An even more preferred amount of aluminum in the alloy is about 1.8 weight percent.
Silicon is present in the alloy in a preferred range of 1.1 to 1.75 weight percent. A more preferred amount of silicon in the alloy is in the range of 1.1 to 1.3 weight percent. An even more preferred amount of silicon in the alloy is about 1.2 weight percent. Chromium is present in the alloy in a preferred range of 1.45 to 1.9 weight percent. A more preferred range is 1.45 to 1.8 weight percent. An even more preferred amount of chromium in the alloy is about 1.6 weight percent. Manganese is present in the alloy in a preferred range of 0.3 to 0.6 weight percent. A more preferred range is 0.3 to 0.5 weight percent. An even more preferred amount of manganese in the alloy is about 0.4 weight percent.
Iron occurs naturally in nickel and is present in a preferred amount less than 0.5 weight percent. A more preferred amount is less than 0.2 weight percent. An even more preferred amount of iron in the alloy is less than 0.1 weight percent. Titanium, zirconium and impurities, such as carbon, are present in the NiAl alloy in an amount preferably less than 0.2 weight percent. A more preferred amount is less than 0.1 weight percent zirconium and less than 0.02 weight percent titanium. An even more preferred amount is less than 0.05 weight percent zirconium and less than 0.01 weight percent titanium. An even more preferred amount is less than 0.005 weight percent titanium. Referring specifically to carbon as an impurity, it should be present at 0.05 weight percent or less. Nickel comprises the remainder of the composition of the alloy.
When used as the electrode material in a spark plug, the NiAl alloy has the considerable advantage of forming a durable oxide film or scale on the electrode that restricts harmful oxidation and sulfidation to reduce corrosion of the electrode. The alloy also improves the performance of the electrode by reducing gap growth.
Other features and advantages will be apparent from the following description, including the drawings, and from the claims.
DESCRIPTION OF THE DRAWING
Fig. 1 is a front view of a spark plug.
DESCRIPTION
Referring to Fig. 1, a spark plug 100 includes an insulator 105, an outer shell 110, a ground electrode 115 attached to outer shell 110, and a firing electrode 120 adjacent to ground electrode 115. A spark gap 125 is defined between ground electrode 115 and firing electrode 120. Ground electrode 115 and firing electrode 120 are made of a nickel, aluminum alloy (NiAl alloy) that includes nickel (Ni), aluminum (Al), titanium (Ti), silicon (Si), manganese (Mn), chromium (Cr), iron (Fe), and zirconium (Zr). Each element contributes to the properties of the NiAl alloy.
Aluminum is present in the NiAl alloy in a preferred range of 0.75 to 2.2 weight percent. A more preferred range is 1.5 to 2.1 weight percent. An even more preferred amount of aluminum in the alloy is about 1.8 weight percent. Aluminum is added to the NiAl alloy primarily because it forms a durable and stable oxide film in the form of aluminum oxide (Al2O3). On an atomic scale, the alloy is made of grains ordered in a grain arrangement. The oxide film is formed in the grain boundaries, where the alloy is likely to be attacked in the processes of oxidation and sulfidation during combustion. These processes corrode the electrodes by causing grains to drop out of the grain boundary. The formation of a durable aluminum oxide film restricts harmful oxidation and sulfidation and, thus, reduces corrosion.
Aluminum also contributes to faster work hardening than would occur during the normal plastic deformation associated with cold working of the alloy. During cold working, larger grains are broken into smaller grains. Because of energy level differences, the aluminum atoms migrate to the grain boundaries. The aluminum atoms are smaller than the nickel atoms they replace, which makes the material harder to work further and thereby improves work hardening. After cold
working, an alloy of nickel and aluminum generally is harder than the alloy without aluminum.
Silicon is present in the alloy in a preferred range of 1.1 to 1.75 weight percent. A more preferred amount of silicon in the alloy is in the range of 1.1 to 1.3 weight percent. An even more preferred amount of silicon in the alloy is about 1.2 weight percent. Silicon forms a durable oxide film similar to the film formed by aluminum. In particular, the silicon undergoes a reaction with oxygen attacking the alloy in the grain boundaries. The reaction produces the oxide, silicon oxide (SiO2), which, in turn, creates a compressive force on the surface to form a protective oxide scale.
Chromium is present in the alloy in a preferred range of 1.45 to 1.9 weight percent. A more preferred range is 1.45 to 1.8 weight percent. An even more preferred amount of chromium in the alloy is about 1.6 weight percent. Chromium is added because it reacts with oxygen to form a durable chromium oxide (Cr2O3) scale with properties similar to the aluminum and silicon oxides. However, the weight percentage of chromium is restricted because its presence reduces thermal and electrical conductivity, both of which must be maintained to ensure performance of the spark plug.
Manganese is present in the alloy in a preferred range of 0.3 to 0.6 weight percent. A more preferred range is 0.3 to 0.5 weight percent. An even more preferred amount of manganese in the alloy is about 0.4 weight percent. Manganese reacts with sulfur present in combustion gases in the combustion chamber more than it reacts with oxygen due to sulfur' s higher level of energy. The reaction produces manganese sulfide (MnS) as a film on the surface of the electrode. This film generates a compressive force on the surface similar to the compressive force produced by silicon oxide. The film and compressive force block additional sulfur and oxygen from passing through to the alloy below.
Iron occurs naturally in nickel and is present in a preferred amount less than 0.5 weight percent. A more preferred amount is less than 0.2 weight percent. An even more preferred amount of iron in the alloy is less than 0.1 weight percent.
Like chromium, the weight percentage of iron is limited because it affects thermal and electrical conductivity.
Titanium and zirconium are present in the alloy because they occur naturally in nickel as trace elements. Together with impurities, such as carbon, they are present in the NiAl alloy in an amount preferably less than 0.2 weight percent. A more preferred amount is less than 0.1 weight percent zirconium and less than 0.02 weight percent titanium. An even more preferred amount is less than 0.05 weight percent zirconium and less than 0.01 weight percent titanium. An even more preferred amount is less than 0.005 weight percent titanium. Referring specifically to carbon as an impurity, it should be present at a maximum of 0.05 weight percent. Titanium forms a durable oxide film that reduces corrosion. However, titanium is more expensive and more difficult to process than aluminum. Zirconium also forms a durable oxide film that reduces corrosion.
Nickel comprises the remainder of the composition of the alloy. Nickel has the beneficial property of high temperature integrity.
The percentages of the elements in the alloy, although reported here as weight percentages, are based on atomic percentages. Table 1 illustrates the weight percentages and atomic percentage of one composition of the alloy. The composition was developed based on the atomic percentages of aluminum, silicon, and chromium necessary to form a durable oxide scale with similar proportions of each oxide. For instance, to have similar proportions of silicon oxide, aluminum oxide, and chromium oxide, the atomic percentages of the elements are one silicon atom for every two aluminum atoms and chromium atoms. From this ratio, the atomic percentages and weight percentages can be calculated. Constraints on the compositions generated by this method are the availability of alloys designed according to this method and manufacturability of the alloy into electrodes.
Table 1
To test the NiAl alloy, ground and firing electrodes were fabricated from the alloy using a composition specified to be within the weight percentage ranges described above. Spark plugs then were fabricated using the electrodes and the spark plugs mounted in combustion engines. Ground and firing electrodes also were made using Champion Alloy 522, and finished spark plugs were installed in internal combustion engines. The engines were operated using leaded fuel . Periodically, the spark gaps were examined for spark gap growth (i.e., the increase in gap distance between the ground and firing electrodes caused by erosion of the electrodes) . After 180 hours of operation, the ground electrode fabricated from Champion Alloy 522 had eroded almost completely. After 200 hours of operation, the ground electrode fabricated from the NiAl alloy showed little erosion of either the ground or firing electrode. An analysis of the results showed a 30-40% increase in performance of the electrode material as measured by reduced gap growth. Results also indicate that the NiAl alloy electrodes provide increased performance when used to combust unleaded fuel .
Other embodiments are within the scope of the following claims.
Claims
1. A nickel, aluminum-based electrode alloy comprising, by weight:
(i) between 0.75 and 2.2 % aluminum; (ii) between 1.1 and 1.75 % silicon;
(iii) between 1.45 and 1.9 % chromium; (iv) less than 0.6 % manganese; (v) less than 0.5 % iron; (vi) less than 0.05 % carbon; (vii) less than 0.2 % of the combination of titanium, zirconium, and impurities; and (viii) the remainder nickel.
2. The nickel, aluminum-based electrode alloy of claim 1, comprising, by weight: (i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.75 % silicon;
(iii) between 1.45 and 1.8 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron; (vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and
(viii) the remainder nickel and impurities.
3. The nickel, aluminum-based electrode alloy of claim 2, comprising, by weight: (i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.75 % silicon;
(iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron; (vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and
(viii) the remainder nickel and impurities.
4. The nickel, aluminum-based elecfrode alloy of claim 3, comprising, by weight:
(i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.3 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
5. The nickel, aluminum-based elecfrode alloy of claim 4, comprising, by weight:
(i) between 1.5 and 2.1 % aluminum;
(ii) approximately 1.2 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
6. The nickel, aluminum-based elecfrode alloy of claim 5, comprising, by weight:
(i) approximately 1.8 % aluminum;
(ii) approximately 1.2 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
7. A nickel, aluminum-based elecfrode alloy comprising, by weight: (i) between 1.5 and 2.1 % aluminum; (ii) between 1.1 and 1.3 % silicon; (iii) between 1.45 and 1.9 % chromium; (iv) less than 0.6 % manganese;
(v) less than 0.1 % iron; (vi) less than 0.01 % titanium; (vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
8. The nickel, aluminum-based electrode alloy of claim 7, comprising, by weight:
(i) between 1.5 and 2.1 % aluminum;
(ii) between 1.1 and 1.3 % silicon;
(iii) approximately 1.6 % chromium; (iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and
(viii) the remainder nickel and impurities.
9. The nickel, aluminum-based electrode alloy of claim 7, comprising, by weight:
(i) between 1.5 and 2.1 % aluminum;
(ii) approximately 1.2 % silicon;
(iii) approximately 1.6 % chromium; (iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and
(viii) the remainder nickel and impurities.
10. The nickel, aluminum-based electrode alloy of claim 7, comprising, by weight:
(i) approximately 1.8 % aluminum;
(ii) approximately 1.2 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
11. A spark plug including a firing electrode and a ground electrode, wherein at least one electrode is comprised of a nickel, aluminum-based alloy comprising, by weight:
(i) between 0.75 and 2.2 % aluminum; (ii) between 1.1 and 1.75 % silicon;
(iii) between 1.45 and 1.9 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.5 % iron;
(vi) less than 0.05 % carbon; (vii) less than 0.2 % of the combination of titanium, zirconium, and impurities; and
(viii) the remainder nickel.
12. The spark plug of claim 11, wherein the ground electrode is comprised of the nickel, aluminum-based alloy.
13. The spark plug of claim 11, wherein the firing elecfrode is comprised of the nickel, aluminum-based alloy.
14. The spark plug of claim 11, wherein the ground elecfrode and the firing elecfrode are comprised of the nickel, aluminum-based alloy.
15. The spark plug of claim 11, wherein the nickel, aluminum-based alloy comprises, by weight:
(i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.75 % silicon; (iii) between 1.45 and 1.8 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
16. The spark plug of claim 15 wherein the nickel, aluminum-based alloy comprises, by weight:
(i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.75 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
17. The spark plug of claim 16 wherein the nickel, aluminum-based alloy comprises, by weight:
(i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.3 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
18. The spark plug of claim 17, wherein the nickel, aluminum-based alloy comprises, by weight:
(i) between 0.75 and 2.2 % aluminum;
(ii) between 1.1 and 1.3 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
19. The spark plug of claim 18, wherein the nickel, aluminum-based alloy comprises, by weight:
(i) between 1.5 and 2.1 % aluminum;
(ii) approximately 1.2 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
20. The spark plug of claim 19, wherein the nickel, aluminum-based alloy comprises, by weight:
(i) approximately 1.8 % aluminum;
(ii) approximately 1.2 % silicon; (iii) approximately 1.6 % chromium;
(iv) less than 0.6 % manganese;
(v) less than 0.1 % iron;
(vi) less than 0.01 % titanium;
(vii) less than 0.02 % zirconium; and (viii) the remainder nickel and impurities.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US107122 | 1979-12-26 | ||
| US10712298A | 1998-06-30 | 1998-06-30 | |
| PCT/US1999/013891 WO2000000652A1 (en) | 1998-06-30 | 1999-06-22 | Spark plug electrode alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1090155A1 true EP1090155A1 (en) | 2001-04-11 |
Family
ID=22314971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99930453A Withdrawn EP1090155A1 (en) | 1998-06-30 | 1999-06-22 | Spark plug electrode alloy |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP1090155A1 (en) |
| WO (1) | WO2000000652A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ297483B6 (en) * | 2001-11-29 | 2006-12-13 | BRISK Tábor a. s. | Spark plug |
| JP4769070B2 (en) | 2005-01-31 | 2011-09-07 | 日本特殊陶業株式会社 | Spark plug for internal combustion engine |
| DE102006023374A1 (en) * | 2006-05-16 | 2007-11-22 | Beru Ag | Nickel-based alloy containing Si Al Si, Mn, and Ti and Zr where the Zr can be replaced completely or partially by Hf useful for production of sparking plug electrodes has decreased burning off liability |
| DE102006035111B4 (en) * | 2006-07-29 | 2010-01-14 | Thyssenkrupp Vdm Gmbh | Nickel-based alloy |
| DE102013004365B4 (en) * | 2013-03-14 | 2015-09-24 | VDM Metals GmbH | Nickel-based alloy with silicon, aluminum and chrome |
| JP6164736B2 (en) * | 2013-08-27 | 2017-07-19 | 日立金属Ｍｍｃスーパーアロイ株式会社 | Ni-base alloy excellent in hot forgeability, high-temperature oxidation resistance and high-temperature halogen gas corrosion resistance, and member using this Ni-base alloy |
| JP7429725B2 (en) * | 2022-02-18 | 2024-02-08 | 日本特殊陶業株式会社 | Spark plug main metal fittings and spark plugs |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6043897B2 (en) * | 1978-09-07 | 1985-10-01 | 日本特殊陶業株式会社 | Nickel alloy for spark plug electrodes |
| JPH02163335A (en) * | 1988-12-15 | 1990-06-22 | Toshiba Corp | Electrode for spark plug |
| JPH08232030A (en) * | 1995-02-23 | 1996-09-10 | Sumitomo Electric Ind Ltd | Electrode material for spark plug |
-
1999
- 1999-06-22 EP EP99930453A patent/EP1090155A1/en not_active Withdrawn
- 1999-06-22 WO PCT/US1999/013891 patent/WO2000000652A1/en not_active Ceased
Non-Patent Citations (1)
| Title |
|---|
| See references of WO0000652A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2000000652A1 (en) | 2000-01-06 |
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