EP0660475A1 - Elektroden für Zündkerzen oder Anzünder und diese enthaltende Zündkerzen oder Anzünder - Google Patents

Elektroden für Zündkerzen oder Anzünder und diese enthaltende Zündkerzen oder Anzünder Download PDF

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Publication number
EP0660475A1
EP0660475A1 EP94309728A EP94309728A EP0660475A1 EP 0660475 A1 EP0660475 A1 EP 0660475A1 EP 94309728 A EP94309728 A EP 94309728A EP 94309728 A EP94309728 A EP 94309728A EP 0660475 A1 EP0660475 A1 EP 0660475A1
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EP
European Patent Office
Prior art keywords
electrode
ruthenium
nickel
aluminium
intermetallic compound
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.)
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Application number
EP94309728A
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English (en)
French (fr)
Inventor
Hermanus De Villiers Steyn
Ira Mervyn Wolff
Rudolf Coetzee
Michael Bernard Cortie
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Mintek
Original Assignee
Mintek
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Filing date
Publication date
Application filed by Mintek filed Critical Mintek
Publication of EP0660475A1 publication Critical patent/EP0660475A1/de
Withdrawn legal-status Critical Current

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    • 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

Definitions

  • THIS INVENTION relates to spark plug or igniter electrodes, including both positive and negative electrodes, tips or inserts for such electrodes, and spark plugs and igniters embodying same.
  • the spark plugs may be of the general nature employed in internal combustion engines for effecting ignition thereof.
  • An igniter may be of the general type for use in turbine engines.
  • spark plugs in particular the electrodes thereof, is of increasing importance in view of the increased demands thereon.
  • This invention seeks to provide inserts or tips for spark plug electrodes, spark plug electrodes and spark plugs embodying same, in which the electrodes are able to stand up to the rigorous use made of them.
  • a spark plug or igniter electrode characterised in that the electrode, or a tip or insert mounted onto or into the electrode, is made at least predominantly of one or more intermetallic compounds having a melting point above 1400°C and wherein the intermetallic compound or compounds is or are chosen to exhibit adequate toughness, resistance to thermal shock, and electrical conductivity.
  • tip is to be interpreted as including a pad, layer, or any other separate element secured to an electrode.
  • a tip is preferably bonded, such as to a nickel or nickel alloy electrode part, by diffusion welding or the like.
  • Preferred features of the invention provide for the intermetallic compound or compounds to be selected from the groups comprising ruthenium and aluminium (herein referred to as ruthenium aluminide); ruthenium, aluminium and nickel; platinum and aluminium; ruthenium and titanium; nickel and aluminium; titanium and aluminium; ruthenium and zirconium; ruthenium and tantalum; iron and aluminium; niobium (columbium) and aluminium; molybdenum and silicon; iridium and niobium; iridium and hafnium; iridium and titanium; iridium and tantalum; and for the intermetallic material optionally to be dispersed in one or more other phases thereby forming a dual- or multi-phase material.
  • ruthenium aluminide ruthenium, aluminium and nickel
  • platinum and aluminium ruthenium and titanium
  • nickel and aluminium titanium and aluminium
  • the intermetallic compounds are solid-state intermediate phases in alloy systems, generally formed between chemically dissimilar metals. They often have relatively simple stoichiometric proportions and often have narrow composition ranges of homogeneity (or even a fixed composition).
  • the nature of atomic bonding may vary from metallic to ionic. They are often believed to have essentially nonmetallic properties such as poor electrical conductivity (S.H. Avner, Introduction to Physical Metallurgy , McGraw-Hill Second Edition, p.149). They have long been known to have high melting points and good oxidation resistance.
  • intermetallic compounds are well researched materials today, and have found a number of applications - however, they have not yet been implemented on the scale envisaged, particularly in high-temperature gas turbines. Care should accordingly be exercised in selecting the intermetallic compound or compounds to be used in implementing the invention.
  • ruthenium aluminide the presently preferred intermetallic compound
  • some other intermetallic compounds exhibit significant toughness at room temperature; have a high melting point; good oxidation resistance; and, outstanding corrosion resistance.
  • the thermo-dynamic stability that these materials exhibit at elevated temperatures and in an aggressive medium is therefore paramount. It has also been demonstrated that these compounds exhibit adequate electrical and thermal conductivity as well as adequate resistance to thermal fatigue.
  • dual or multi phase materials comprising ruthenium aluminide, in an excess of ruthenium; preferably containing between 80 and 99 mass percent Ru; and most preferably about 90 mass percent Ru.
  • intermetallic compounds such as ruthenium aluminide are, however, difficult to manufacture by conventional techniques such as melting and casting, in view of their very high melting points (approximately 2050°C for ruthenium aluminide); the aggressive attack of ruthenium aluminide and other intermetallics on refractories in the molten state; and, the volatilisation of aluminium consequent on the high temperature.
  • the aluminium powder particle size range was between 22 and 72 ⁇ m and that of the precious metal was from 13 to 58 ⁇ m on average.
  • the preferred powder size was about 22 ⁇ m in the case of aluminium and about 13 ⁇ m in the case of the precious metal.
  • the compaction pressure is preferably chosen from the range between 415 and 750 MPa and preheating at a temperature of about 500°C is preferably carried out preparatory to sintering at a temperature of about 1600°C for a period of about 12 hours.
  • a number of other manufacturing processes can be used without deviating from the scope of this invention. These include, but are not limited to, a variety of melting processes, forming processes, and a variety of powder metallurgy processes such as sintering and metal spraying processes. Material may also be produced by any combination of the above processes without deviating from the scope hereof.
  • the invention also provides a spark plug or other igniter embodying one or more electrodes as defined above. Whilst usually both or all of the electrodes will be made according to the invention, it may be that only one, for example the central electrode, employs an intermetallic compound.
  • the spark plugs may be utilised in engines operating on leaded or unleaded fuels. Although ruthenium aluminide, with compositions close to 50 atomic per cent Ru, is attacked by leaded fuels, ruthenium-rich ruthenium aluminide may be utilised in engines operating on leaded fuels.
  • thermal conductivity of NiAl has been reported to be higher than that of some nickel-based superalloys. It is known that a correlation exists between thermal conductivities and electrical conductivities of metallic materials.
  • an experimental electrode insert 1 of 1mm in diameter for centre (negative) electrode 2 of a spark plug 3 was machined from the respective experimental material to the required geometry.
  • the electrode inserts were incorporated into standard spark plug configurations as centre electrodes only, whereby each experimental electrode insert was held within a nickel socket, and was contacted to the nickel by cold deforming.
  • the spark intensity of the experimental spark plugs was similar. Transfer of the spark took place from the experimental electrode material and not from the surrounding nickel jacket, confirming sufficient electrical conductivity of the ruthenium aluminide.
  • the lengths of the ruthenium aluminide electrode inserts were varied slightly for comparative purposes.
  • the spark plugs were mounted in a standard six-cylinder internal combustion engine, connected to a dynamometer capable of maintaining the engine at a constant speed, with parameters such as torque, power, engine coolant temperature, and fuel consumption being directly measurable.
  • the performance was subsequently determined under full- and partial axle loading at speeds up to 5000 revolutions per minute. Testing was carried out using leaded fuel consistent with an octane rating of 93.
  • the performance of the electrodes was further evaluated by microstructural analysis of the working tip. Wear characteristics were monitored by means of computerised profile scanning on a Mitutoyo Scanpak-3 V2.10.
  • Spark plugs containing these electrode inserts were tested in a dynamometer-mounted engine that was run on leaded fuel at engine speeds up to 5 000 r/min at full open throttle and full load.
  • the electrode configuration was similar to that of a standard commercial spark plug which has a gold-palladium electrode tip.
  • Spark plugs containing the experimental ruthenium aluminide centre electrodes were tested in two experiments (40 and 48 hours respectively) to compare erosion rates. The tests were conducted at full load and at engine speeds between 3500 and 5500 r/min.
  • Centre electrode inserts of arc-melted alloys containing 85, 90 and 95 mass per cent ruthenium were subjected to a limited (8-hour) test in an engine, running on unleaded fuel at 35000r/min and full load.
  • a standard commercial spark plug with a gold-palladium centre electrode was used as reference in this experiment to compare erosion results.
  • Spark plugs containing these inserts were tested in an engine that was run on unleaded fuel at full load at the engine speed where peak torque is delivered.
  • a standard spark plug with a nickel-base centre electrode of diameter 2,52 mm was fitted as a reference.
  • the face of the RuAl electrodes was therefore 0,79 mm2 compared to that of 4,99 mm2 of the reference nickel electrode.
  • the sparking surface of the reference nickel electrode was therefore more than six times larger than that of the ruthenium aluminide electrode inserts.
  • the average erosion rate over the face of the reference nickel electrode was 0,8 ⁇ m per hour, and at the centre it was 0,35 ⁇ m per hour.
  • Electrode erosion was again measured after 144 and 216 cumulative test hours. Erosion measured over the face of the reference electrode was misleading, because sparking also occurred from the side of the centre electrode facing the positive electrode. This led to low erosion rates measured at the electrode centre and over the electrode face of the reference spark plug.
  • the average erosion rate over the face of the reference nickel-alloy electrode was similar after 72, 144 and 216 hours. It was evident that a limited amount of sparking occurred from the nickel base supporting the insert, while sever erosion was measured at the corresponding. edge of the reference electrode. Table 4 shows the results obtained. TABLE 4 Erosion rates after an additional 144 hours endurance testing AREAS WHERE EROSION WAS MEASURED EROSION RATE ( ⁇ m/h) 72 hours 144 hours 216 hours Ni BASED REFERENCE ELECTRODE Spark Face 0,80 0,70 0,77 Electrode Centre 0,35 0,40 0,41 Side Facing Pos.
  • the erosion resistance of the ruthenium aluminide alloys were comparable to that of the reference nickel-alloy electrodes irrespective of the fact that the reference nickel electrode had a sparking surface more than 6 times larger than that of the experimental ruthenium aluminide electrodes.
  • the reference nickel-alloy electrodes showed very stable erosion on the sparking surface of the centre electrode end.
  • the 63 atomic per cent Ru alloy apparently showed a sharp increase in erosion after 72 hours testing. This observation is based on one sample only.
  • the 68 atomic per cent ruthenium alloy compared exceptionally well with the reference nickel-alloy electrodes of some 6 times the size (effective area).
  • nickel can be added to the RuAl phase in such a way that part of the ruthenium is substituted with the cheaper nickel, without deleteriously affecting the desirable properties of the RuAl-base phase.
  • This type of substitution is considered possible because both Ru and Ni form B2 (body centred cubic) aluminide compounds with aluminium, and the atomic radii and electronegativities of Ru and Ni are sufficiently close to allow the substitution of one for the other in the crystal lattice of RuAl.
  • the metallic atomic radius of Ru is 0,133 nm while that of Ni is 0,124 nm, and the electronegativities are 2,2 and 1,8 respectively).
  • the alloys were then examined using metallography, X-ray diffraction and hardness testing. It was found that the addition of Ni to RuAl, or Ru to NiAl, raised the hardness of the material considerably.
  • Ni-Al-Ru ternary system compounds with the general formula Ni x Ru 1-x Al have the same B2 structure and Ni can substitute at least partially for Ru. Ni can also substitute for Ru in other parts of the Ru-Al phase system e.g. in the Ru-rich sections where high durability of electrode inserts has been proven experimentally. Ni-Al-Ru alloys with a combined Ru+Ni content of 42 or more atomic per cent, are suitable to be used in spark plug electrodes.
  • Ni atoms can substitute for Ru atoms explains the diffusion bonding that was observed to have taken place during engine operation.
  • Diffusion bonding as well as other welding techniques such as (but not limited to) electrical resistance welding can be harnessed as a production technique, in particular to bond tips, of or containing, intermetallic compounds to a nickel or nickel alloy electrode.
  • compositions may deviate from stoichiometric intermetallic compositions and may therefore include multi-phase structures without departing from the scope hereof.
  • Intermetallic compounds with melting points above 1400°C in a matrix of other metals may according to this invention be produced in any ratio by means of any suitable process.
  • powdered or sub-divided intermetallic material may be embodied in a ductile metallic phase thus yielding a composite material embodying good arc erosion resistance and good workability.
  • a dispersion of intermetallic phases with melting points above 1400°C may also be used to restrict grain growth of a ductile metallic phase of a multi-phase or composite material at elevated temperatures.
  • the ductile metallic phase could include metals such as Ni, Pt, Au, Pd, Ag, or any other suitable metal or any combination of such metals.
  • intermetallic material may be sintered into the ceramic insulator body to form a centre electrode.
  • the intermetallic material may be manufactured by a number of different processes without departing from the scope hereof. These include a variety of powder metallurgical processes, a variety of metal-spraying processes and a number of melting techniques.
  • Spark plugs and igniters typically also contain ceramic components such as alumina insulators. Ceramic materials are also increasingly considered for the manufacture automotive components.
  • the intermetallic compounds according to this invention lend themselves to sintering processes compatible with ceramic materials. It is possible to sinter ceramic components and intermetallic compounds according to this invention in one production step. Should a specific shrinkage during sintering be required, this could be achieved by mixing specific amounts of pre-reacted intermetallic powders with elemental metal powders.

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  • Spark Plugs (AREA)
EP94309728A 1993-12-23 1994-12-22 Elektroden für Zündkerzen oder Anzünder und diese enthaltende Zündkerzen oder Anzünder Withdrawn EP0660475A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA937335 1993-12-23
ZA937335 1993-12-23

Publications (1)

Publication Number Publication Date
EP0660475A1 true EP0660475A1 (de) 1995-06-28

Family

ID=25583284

Family Applications (1)

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EP94309728A Withdrawn EP0660475A1 (de) 1993-12-23 1994-12-22 Elektroden für Zündkerzen oder Anzünder und diese enthaltende Zündkerzen oder Anzünder

Country Status (11)

Country Link
EP (1) EP0660475A1 (de)
JP (1) JPH07235364A (de)
KR (1) KR950021926A (de)
CN (1) CN1110022A (de)
AU (1) AU675023B2 (de)
BR (1) BR9405233A (de)
CA (1) CA2138732A1 (de)
NZ (1) NZ270219A (de)
RU (1) RU94044329A (de)
TW (1) TW326593B (de)
ZA (1) ZA9410180B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19939319A1 (de) * 1999-07-29 2001-02-08 Bosch Gmbh Robert Zündkerze für eine Brennkraftmaschine
FR2869163A1 (fr) * 2004-04-20 2005-10-21 Bosch Gmbh Robert Procede de fabrication de l'electrode centrale d'une bougie d'allumage
WO2007112936A2 (de) * 2006-03-30 2007-10-11 W. C. Heraeus Gmbh Verbund aus intermetallischen phasen und metall
WO2008093922A1 (en) 2007-01-31 2008-08-07 Yura Tech Co., Ltd. Ignition plug
US10815896B2 (en) 2017-12-05 2020-10-27 General Electric Company Igniter with protective alumina coating for turbine engines

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7969078B2 (en) * 2008-05-19 2011-06-28 Federal Mogul Ignition Company Spark ignition device for an internal combustion engine and sparking tip therefor
WO2011066425A2 (en) * 2009-11-24 2011-06-03 Federal-Mogul Ignition Company Spark plug with platinum-based electrode material
US8334642B2 (en) * 2010-05-11 2012-12-18 Caterpillar Inc. Spark plug
CN103229372A (zh) * 2010-07-29 2013-07-31 美国辉门（菲德尔莫古）点火系统有限公司 用于与火花塞一起使用的电极材料
US20130216846A1 (en) * 2010-09-09 2013-08-22 Zebin Bao Alloy material for high temperature having excellent oxidation resistant properties and method for producing the same
JP6035177B2 (ja) 2012-08-20 2016-11-30 株式会社デンソー 内燃機関用のスパークプラグ
JP6038698B2 (ja) * 2013-03-22 2016-12-07 日本碍子株式会社 セラミックス部材及び半導体製造装置用部材

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2005649A (en) * 1977-09-22 1979-04-25 Johnson Matthey Co Ltd Electrodes
WO1992010868A1 (de) * 1990-12-13 1992-06-25 Robert Bosch Gmbh Elektrode und verfahren zu ihrer herstellung

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE870559A (fr) * 1977-09-22 1979-01-15 Johnson Matthey Co Ltd Electrodes
JPS5581477A (en) * 1978-12-15 1980-06-19 Nippon Soken Ignition plug
JPS61135082A (ja) * 1984-12-06 1986-06-23 日本特殊陶業株式会社 スパ−クプラグ
JPH0828312B2 (ja) * 1987-11-09 1996-03-21 ニチコン株式会社 電解コンデンサ用アルミニウム合金電極
JP2738766B2 (ja) * 1990-02-21 1998-04-08 日本タングステン株式会社 化合物焼結体の製造方法
JP2858910B2 (ja) * 1990-09-14 1999-02-17 昭和アルミニウム株式会社 電解コンデンサ電極用アルミニウム箔

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2005649A (en) * 1977-09-22 1979-04-25 Johnson Matthey Co Ltd Electrodes
WO1992010868A1 (de) * 1990-12-13 1992-06-25 Robert Bosch Gmbh Elektrode und verfahren zu ihrer herstellung

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19939319A1 (de) * 1999-07-29 2001-02-08 Bosch Gmbh Robert Zündkerze für eine Brennkraftmaschine
DE19939319B4 (de) * 1999-07-29 2004-05-06 Robert Bosch Gmbh Zündkerze für eine Brennkraftmaschine
FR2869163A1 (fr) * 2004-04-20 2005-10-21 Bosch Gmbh Robert Procede de fabrication de l'electrode centrale d'une bougie d'allumage
DE102004018933B4 (de) * 2004-04-20 2014-10-09 Robert Bosch Gmbh Verfahren zur Herstellung einer Mittelelektrode einer Zündkerze
WO2007112936A2 (de) * 2006-03-30 2007-10-11 W. C. Heraeus Gmbh Verbund aus intermetallischen phasen und metall
WO2007112936A3 (de) * 2006-03-30 2008-06-19 Heraeus Gmbh W C Verbund aus intermetallischen phasen und metall
WO2008093922A1 (en) 2007-01-31 2008-08-07 Yura Tech Co., Ltd. Ignition plug
EP2122156A4 (de) * 2007-01-31 2012-01-04 Yura Tech Co Ltd Zündkerze
US10815896B2 (en) 2017-12-05 2020-10-27 General Electric Company Igniter with protective alumina coating for turbine engines

Also Published As

Publication number Publication date
TW326593B (en) 1998-02-11
RU94044329A (ru) 1996-10-27
ZA9410180B (en) 1995-08-29
KR950021926A (ko) 1995-07-26
NZ270219A (en) 1997-03-24
CA2138732A1 (en) 1995-06-24
AU8169794A (en) 1995-07-13
BR9405233A (pt) 1995-08-01
CN1110022A (zh) 1995-10-11
JPH07235364A (ja) 1995-09-05
AU675023B2 (en) 1997-01-16

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