CA2053454A1 - Extended life ceramic igniters - Google Patents
Extended life ceramic ignitersInfo
- Publication number
- CA2053454A1 CA2053454A1 CA 2053454 CA2053454A CA2053454A1 CA 2053454 A1 CA2053454 A1 CA 2053454A1 CA 2053454 CA2053454 CA 2053454 CA 2053454 A CA2053454 A CA 2053454A CA 2053454 A1 CA2053454 A1 CA 2053454A1
- Authority
- CA
- Canada
- Prior art keywords
- ceramic
- igniter
- active metal
- braze
- solder
- 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.)
- Abandoned
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 55
- 229910000679 solder Inorganic materials 0.000 claims abstract description 32
- YXTPWUNVHCYOSP-UHFFFAOYSA-N bis($l^{2}-silanylidene)molybdenum Chemical compound [Si]=[Mo]=[Si] YXTPWUNVHCYOSP-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910021343 molybdenum disilicide Inorganic materials 0.000 claims abstract description 16
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 238000005476 soldering Methods 0.000 claims abstract description 7
- 229910052751 metal Inorganic materials 0.000 claims description 39
- 239000002184 metal Substances 0.000 claims description 39
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 17
- 229910052802 copper Inorganic materials 0.000 claims description 17
- 239000010949 copper Substances 0.000 claims description 17
- 229910052709 silver Inorganic materials 0.000 claims description 16
- 239000004332 silver Substances 0.000 claims description 16
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 14
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 150000004767 nitrides Chemical class 0.000 claims description 11
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 10
- 229910052725 zinc Inorganic materials 0.000 claims description 10
- 239000011701 zinc Substances 0.000 claims description 10
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 8
- 229910052793 cadmium Inorganic materials 0.000 claims description 8
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 8
- 229910052718 tin Inorganic materials 0.000 claims description 8
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- 239000010936 titanium Substances 0.000 claims description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 6
- 239000000945 filler Substances 0.000 claims description 6
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052738 indium Inorganic materials 0.000 claims description 6
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 5
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 5
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910010293 ceramic material Inorganic materials 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 239000010931 gold Substances 0.000 claims description 3
- 239000000155 melt Substances 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052763 palladium Inorganic materials 0.000 claims description 3
- 229910052582 BN Inorganic materials 0.000 claims description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 2
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 2
- 229910020968 MoSi2 Inorganic materials 0.000 claims 3
- 238000004519 manufacturing process Methods 0.000 claims 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 abstract description 10
- 229910010271 silicon carbide Inorganic materials 0.000 abstract description 9
- 238000002844 melting Methods 0.000 abstract description 2
- 230000008018 melting Effects 0.000 abstract description 2
- 150000002739 metals Chemical class 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- QFXZANXYUCUTQH-UHFFFAOYSA-N ethynol Chemical group OC#C QFXZANXYUCUTQH-UHFFFAOYSA-N 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000005219 brazing Methods 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010285 flame spraying Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 241001279686 Allium moly Species 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000012093 association test Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000003870 refractory metal Substances 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
- F23Q7/22—Details
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Resistance Heating (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Electrical connections are made to ceramic igniters which contain molybdenum disilicide, silicon carbide, and mixtures thereof as the conducting ceramic component of the igniter by forming a braze pad on the igniters and then soldering an elecrical wire to the braze pad with a solder having a melting temperature greater than 500 degrees C.
Electrical connections are made to ceramic igniters which contain molybdenum disilicide, silicon carbide, and mixtures thereof as the conducting ceramic component of the igniter by forming a braze pad on the igniters and then soldering an elecrical wire to the braze pad with a solder having a melting temperature greater than 500 degrees C.
Description
~53~5~
Docket: P-2450 EXTENDED LIFE CER~MIC IGNITERS
SCOTT R. AXELSON
187 Hudson St.
Northboro, MA 01532 BRADLEY J. MIT~FR
3906 Laurel Oak Drive MurrysYille, PA 15668 TECHNICAL FIELD
This invention relates to ceramic igniters and an improved method of ~aking necessary electrical connections thereto. More particularly, the invention re~ates to ceramic igniters which contain molybdenum disilicide, silicon carbide, and mixtures thereof as the conducting ceramic component of the igniter.
BACKGROUND OF THE INVENTION
Although ceramic igniters have been known for many yèars, c.f. U.S. Pat. Nos. 3,875,477, 3,928,910 and Re.
29,853, there has been a continual problem of making electrical contacts to the ceramic bodies wherein the connections neither cause premature failure of the igniter nor substantially increase in contact resistance over the projected life of the device.
~ O ~ 3 ~ ~ 4 The preparation of ceramic ignit~rs, which entail electrical conduction through a ceramic componenk, present substantially different problems than mere physical attachment to a ceramic body which is to be utiliz~d only as a physical support for electrical components, i.e. in which no electrical conduction through the ceramic is required.
Forming a conductive interface between a metal and a ceramic requires not only that the thermal expansion characteristics be made similar but also that an electrical path be formed lo which is sufficiently continuous to endure for many thousands of cycles of extreme temperature change.
Furthermore, the metal and ceramic also must not react during operation so as to form an interface that would be more resistive than either the metal or the ceramic. Any chemical interaction that is used in forming the combined mechanical and electrical connection must not also form a material composition that would degrade or change during continued cyclic operations. Mechanical failure or chemical deterioration, i.e. oxidation, must both be avoided since either could cause the interface to have an increase in resistance greater than that of the metal and ceramic. The necessity of producing a combination of adhesion and a stable electrical path presents a unique problem when extended cyclic operation as is required in the igniters of this invention.
Previous attempts at making electrical connections for ceramic igniters have been varied. U.S. Pat. No. 3,875,477 discloses so doing by (i) lightly sandblasting portions of a silicon carbide igniter in the areas where the electrical contacts are to be made, (ii) coating the sandblasted terminal ends with aluminum metal or an aluminum alloy either by dipping into molten metal or by flame spraying, and (iii) using a refractory, electrically insulating cament of the high alumina type. U.S. Pat. Nos. 3,928,910 and Re.
Docket: P-2450 EXTENDED LIFE CER~MIC IGNITERS
SCOTT R. AXELSON
187 Hudson St.
Northboro, MA 01532 BRADLEY J. MIT~FR
3906 Laurel Oak Drive MurrysYille, PA 15668 TECHNICAL FIELD
This invention relates to ceramic igniters and an improved method of ~aking necessary electrical connections thereto. More particularly, the invention re~ates to ceramic igniters which contain molybdenum disilicide, silicon carbide, and mixtures thereof as the conducting ceramic component of the igniter.
BACKGROUND OF THE INVENTION
Although ceramic igniters have been known for many yèars, c.f. U.S. Pat. Nos. 3,875,477, 3,928,910 and Re.
29,853, there has been a continual problem of making electrical contacts to the ceramic bodies wherein the connections neither cause premature failure of the igniter nor substantially increase in contact resistance over the projected life of the device.
~ O ~ 3 ~ ~ 4 The preparation of ceramic ignit~rs, which entail electrical conduction through a ceramic componenk, present substantially different problems than mere physical attachment to a ceramic body which is to be utiliz~d only as a physical support for electrical components, i.e. in which no electrical conduction through the ceramic is required.
Forming a conductive interface between a metal and a ceramic requires not only that the thermal expansion characteristics be made similar but also that an electrical path be formed lo which is sufficiently continuous to endure for many thousands of cycles of extreme temperature change.
Furthermore, the metal and ceramic also must not react during operation so as to form an interface that would be more resistive than either the metal or the ceramic. Any chemical interaction that is used in forming the combined mechanical and electrical connection must not also form a material composition that would degrade or change during continued cyclic operations. Mechanical failure or chemical deterioration, i.e. oxidation, must both be avoided since either could cause the interface to have an increase in resistance greater than that of the metal and ceramic. The necessity of producing a combination of adhesion and a stable electrical path presents a unique problem when extended cyclic operation as is required in the igniters of this invention.
Previous attempts at making electrical connections for ceramic igniters have been varied. U.S. Pat. No. 3,875,477 discloses so doing by (i) lightly sandblasting portions of a silicon carbide igniter in the areas where the electrical contacts are to be made, (ii) coating the sandblasted terminal ends with aluminum metal or an aluminum alloy either by dipping into molten metal or by flame spraying, and (iii) using a refractory, electrically insulating cament of the high alumina type. U.S. Pat. Nos. 3,928,910 and Re.
2~S3~
29,853 disclose gas igni~ers having elec~rical leads bonded into physical slots of a ceramic (SiC) body by high temperature flame or plasma spraying which is not only intended to secure the inserted leads into their respective slots but also to fully and continuously encase the terminal parts of the igniter. Co-owned U.S. Appln. Ser. No. 2S8,307 discloses molybdenum disilicide containing ceramic igniters in which a simple machine screw and nut assembly is placed through machined holes in the ceramic body~
Each of the above connection means has suffered from the problem of either substantially increased resistance with extended use, i.e. the resistance increases by 5, 10 or more percent after cycling through 100,000 on/off cycles, or failing to be commercially reproducible. Such larye increases in rPsistance are a problem to the iyniter industry because an igniter mus~ be capable of igniting ~uel gases throughout an extended lifetime of the appliance, at voltages which at times are as low as 85% of the standard operating voltage (20.4 instead of ~.0 v) which often occur during "brownouts" or peak el~ctrical demand periods.
Natural gas ignites at about 1050C. and propane gas ignites at about 960C. When the available voltage decreases, i.e.
to 85% of the nominal voltage, an igniter temperature below that required for gas ignition could occur, particularly in older igniters in which the electrical contact has experienced severe deterioration. Thus, there is a need for an igniter which, after 100,000 cycles, does not exhibit any substantial increase in its resistance due to the electrical contact, and preferably has a low increase in total resistance, i.e. that due to both the igniter itself and the electrical connection.
U.S. Pat. No. 4,512,871 discloses an oxygen sensor with a heater in which a non-electrically conducting ceramic body 2 ~ ~i 3 ~ -.e, is screen prinked with an electrically conductive circuit which terminates in a pair of pads to which electrical contacts are made by brazing. The ceramic body is an insulator and merely functions as a physical support. Thus 5 the problem of forming an improved electrically conductive connection is not ~aced by the patent.
Accordingly, it is an object of the present invention to produce an improved ceramic igniter which will have less than about a 2~ change in contact resistance of the contacts lo after 100,000 on/off cycles and which can be reproducibly manufactured.
It is a further object to produce such an igniter having less than a about 2.5% change in contact resistance after being continuously powered at operating temperature for 2000 hours.
It is a further object to produce such an igniter from a ceramic composition comprising molybdenum disilicide, silicon carbide, or mixtures thereof as ~he conducting ceramic.
These and still further objects will be apparent from the ensuing detailed description of the invention.
SUMMARY OF THE INVENTION
Ceramic igniters are prepared by (i) forming a ceramic igniter body having a molybdenum disilicide content of at least about 20 volume percent at the points at which the electrical contacts are to be made, (ii) forming two pads of an active metal braze on the body at those points, and (iii) soldering electrical leads to said pads by means of a solder which melts at a temperature of greater than about 500C.
20ri~r,~
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a top view of a preferred igniter body with connecting leads soldered to braze pads in accordance with this invention.
S DESCRIPTION OF THE PgEFERRED EMBODIMENTS
The ceramic igniters of the present invention comprise a non-conductive ceramic in combination with an electrically conductive ceramic. The improved electrical connections to the ceramic igniters are produced by forming a braze pad on the igniters and then soldering an elec~rical wire to the braze pad. The igniters prepared with ~wo such electrical connections may be reproducibly produced commercially and furthermore exhibit less than about a 2% change in contact resistance after being subjected to 100,000 on/off cycles.
Also, the igniters exhibit less than about a 2.5% change in contact resistance after being continuously powered at 26.4 volts at elevated temperature (1275 - 1500C.) for 2000 hours. The conductive component of the ceramic is preferably comprised of molybdenum disilicide, silicon carbide, or a mixture thereof. More preferably a mixture of molybdenum disilicide (MoSi2) and silicon carbide (SiC), as disclosed in U.S. Pat. Appln. Ser. No. 258,307 o~ Washburn, filed October 14, 1988, is used. The disclosure and subject matter of Washburn is incorporated herein by reference.
The igniter preferably comprises about 40 to 70 volume percent of a nitride ceramic and about 30 to 60 volume percent MoSi2 and SiC in a volume ratio of from about 1:3 to 3:1. A more preferred igniter has a varying composition as described by Washburn and as indicated in Fisure 1 hereof.
In this case, the chemical composition of the igniter 10 is varied from a high resistive portion 12 through an intermediate portion 14 to a highly conductive portion 16.
Alternatively and even more preferably the intermediate ~ ~ r~
portion 14 i5 omitted (for ease of manufacturiny). The conductive portion is provided with the two active metal braze pads 18 and 18~ to w~ich electrical leads 20 and 20' are respec~ively soldered in accordance with this invention.
The highly resistive portion 12 of the igniter 10 is preferably comprised of about 50 to 70 volume percent nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ratio of about 1.~. The intermediake portion 14, when present, is preferably comprised of about 50 to 70 volume percent nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ratio of about 1:1.
The highly conductive portion 16 is preferably comprised of about 45 to 55 volume percent nitride ceramic and about 45 to 55 volume percent MoSi2 and SiC in a volume ratio of from about 1:1 to about 3:2~ By ~highly resistive" is meant that the section has a resistivity in the temperature range of 1000 to 1600C. of at least about o.04 ohm-cm, preferably at least about 0.07 ohm-cm. By ~highly conductive" is meant that the section has a resistivity in the temperature range of 100 to 800C. of less than about 0.005 ohm-cm, preferably less than about 0.003 ohm-cm, and most prefer~bly less than about 0.001 ohm-cm.
Suitable nitrides for use as the resistive component of the ceramic igniter include silicon nitride, aluminum nitride, boron nitride, and mixtures thereof. Preferably the nitride is aluminum nitride.
The first step to forming the electrical connections of the present invention is to produce a braze pad or area on opposite ends of the highly conductive portions of the ceramic igniter. To obtain the high degree of adhesion to the ceramic which is required, a braze which contains an active metal is utilized. A metal is considered "active"
~3~
herein if it has the ability to wet and react with the ceramic materials suf~iciently to provide a~herence thereto by iller metals contained in the braze. Examples of specific active metals include titanium, zirconium, niobium, nickel, palladium, and gold. Preferably the active metal is titanium or zirconium. In addition to the active metal, the braze contains one or more filler metals such as silver, copper, indium, tin, zincl lead, cadmium, and phosphorous.
Preferably a mixture of filler metals is used. Most preferably, the braze will comprise titaniu~ as the active metal and a mixture of copper and silver as the filler metal.
Generally, the braze will contain in weight percent about 0.1 to about 5 weight percent active metal and about 99.9 to about 95 weight percent filler metal. Suitable such brazes are commercially available under the trade name Lucanex from ~ucasMilhaupt, Inc. and Cusil from GTE Products Corporation. Specific brazes found useful herein include:
Lucanex 721 and Cusil Braze, each of which nominally contain 70.5% silver, 27.5~ copper, and 2% titanium.
- Electrical wire leads are then connected to the braze pads by a solder. The solder must be able to withstand temperatures of about 450C. during use of the igniter without degradation and also must have a low resistivity.
Generally, a solder having a melting point of greater than about 500C., preferably greater than about 600C. Suitable such solders are those which contain in weight percent about 1 to about 90% silver, about 5 to about 80% copper, about 5 to about 40% zinc, and up to about 40% of one or more metals selected from aluminum, tin, indium, phosphorous, cadmium, and nickel. Preferably, the solder will contain about 10 to 70% silver, about 10 to 70% copper, about 10 to 35~ zinc, and up to 30% of the other metals. Most preferably, the ~53~
solder will contain about 15 to 60~ silver, about 10 to 60%
copper, about 12 to 30% zinc, and up to about 30% o~ the other metals.
Suitable such solders are commercially available under the trade names Easy-Flo from Handy ~ Harmon Co. and Safety-Silv from J.W. Harris Co., Inc. A specific solder found useful herein is Easy-Flo 45 which nominally contains 45% silver, 15% copper, 16% xinc and 24% cadmium. Other specific solders which may be used include Safety-Sil~ 1200 10which nominally contains 56% silver, 22% copper, 17% zinc, and 5% tin, and Safe~y-Silv 1577 which nominally contains 25% silver, 52%.5 copper, and Z2.5 zinc.
To perfoxm the soldering of the wires to the braze pads, it has been found advantageous to apply the solder first to the metal wire. When the wire is placed on the braze pad on the igniter and then heated ~o attach it, the solder can flow from the wire to the brazed region to make the connection. This method minimizes the amount of time during which the braze is heated to above 500C, which will minimize/prevent oxidation of the braze pad by the air before it becomes coated with the solder. Oxidation is detrimental since it could prevent a solid chemical bond from forming and could result in mechanical failure and/or an electrical interface having a resistance higher than that of either the metal wire or ceramic igniter.
The practice of the present invention can be further appreciated from the following non-limiting examples and comparative examples in which all parts and percents are by weight unless otherwise specified.
30Exam~le 1 A double-legged triple composition hairpin or U-shaped ~3~
ceramic igniter as shown in Fig. 1 is prepared from ~luminum nitride, silicon carbide, an~ molybdenum disilicide in accordance with the teachinys of U.S.S.N. 258,307, Washburn.
By volume percents, the conductive portion contains 50%
aluminum ni~ride, 30% moly~den~m disilicide, and Z0% silicon carbide; the intermediate portion contains 60~ aluminum nitride, 20% molybdenum disilicide, and 20~ silicon carbide;
and the resistive portion contains 60% aluminum nitride, 13%
molybdenum disilicide, and 27~ silicon carbide.
To form a braze pad on each of the legs of the igniter, an active metal brazing paste, Lucenex 721, is brushed onto - a 0.06" x 0.25" area of each of the legs. The paste is heated by means of a refractory metal furnace under a high vacuum to a temperature of 875C. for 10 minutes to form the pads.
To adhere a conventional copper electrical wire to each of the braze pads, Easy-Flo 45 Solder (45% silver, 15%
copper, 16% zinc, and 24~ cadmium) is used. The soldering is performed using an oxy-acetylene torch as a heat-source.
A standard silver solder flux is first brushed onto the braze pad to clean the surface. Then the wire is heated and the solder introduced to the heated wire. The molten solder flows onto the wire in less than about 5 seconds. The solder-containing end of the wire is placed on the pre-fluxed, braze pad of the igniter and heated with the oxy-acetylene torch, allowing the silver solder to melt and flow onto the braze pad for about less than 5 seconds and then removed. The wire is held in place for an additional 5 seconds until the solder hardens by cooling.
To evaluate the performance of the resultant electrical connection, the igniter is subjected to the standard American Gas Association test for evaluation of 2~3~ 3~
thermoelectric devices, ANSI Test Procedure Z 21.20, 1g89, pp.lZ-13. The test entails cycling the igniter through 100,000 on/off sequences and determining the percent resistance changes of the total device and of the igniter body. The resistance chang~ due to the electrical contact is then calculated by diference.
~ he results from duplicate samples prepared as above and having a~erage initial igniter temperatures o~ 12~5 and 1293~C. respectively are:
Resistance Chanqes. %
Sample ?otal Ianiter Only contact Only A 26.8 25.6 1.2 B 21.5 20.8 0.7 The procedure of Example 1 is repeated except that the Lucanex 721 Braze is replaced with Cusil Braze which has the same nominal composition. The results from duplicate samples ha~ing average initial igniter temperatures of 1283 and 1282C. are:
Resistance Chanaes, %
Sample Total Ianiter OnlY Contact OnlY
C 20.0 18.8 1.2 D 21.0 19.5 1.5 Com~arative ~xamPle A
The procedure of Example 1 is repeated with a different solder, Realistic Electrical Solder which contains 60% tin and 40~ lead. Attempts to solder the wires to the braze pads using an oxyacetylene torch, a propane torch, and an electrically heated soldering iron were unsuccessful. The solder did not bond the wires to the braze.
~3~
Example 3 The prGcedure o~ Example 1 is repeated except that the intermediate portion o~ the ceramic i~niter is omi~ted and the igniter is evaluated in a constant~on test at 24.0 V for 2,350 hours. Four such samples are evaluated and are found to hav~ a percent contact resistance at the end of the test of 0.82%, 0 4 ~3%, 0.95% and 0~.
ExamPle 4 The procedure of Example 3 is repeated except that the solder is Safety-Silv 1577. The percentage change in contact resistance after the specified number of hours during a constant-on test for multiple samples is Resistance Chanaes~_~
Sample o 840 1800 2472 1 o 1.4 1.4 0.7 2 0 1.4 2.1 . 0.7 3 0 1.4 2.3 0.8 4 0 1.4 2.1 0.7 0 2Ø 2.1 0.7 6 0 1.4 2.2 1.5 Example 5 The procedure of Example 4 is repeated except that the solder is Safety-Silv 1200. The percentage change in contact resistance after the specified number of hours during a constant-on test for mul~iple samples is:
Resistance ChangLes %~
SamPle 0 768 153~2328 3000 1 0 0.6 0 2.1 0 2 0 0 1.42.2 0 3 0 0.6 1.42.0 0.7 4 o 0.6 1.32.1 2.2 0 0.6 0 2.1 0.7
29,853 disclose gas igni~ers having elec~rical leads bonded into physical slots of a ceramic (SiC) body by high temperature flame or plasma spraying which is not only intended to secure the inserted leads into their respective slots but also to fully and continuously encase the terminal parts of the igniter. Co-owned U.S. Appln. Ser. No. 2S8,307 discloses molybdenum disilicide containing ceramic igniters in which a simple machine screw and nut assembly is placed through machined holes in the ceramic body~
Each of the above connection means has suffered from the problem of either substantially increased resistance with extended use, i.e. the resistance increases by 5, 10 or more percent after cycling through 100,000 on/off cycles, or failing to be commercially reproducible. Such larye increases in rPsistance are a problem to the iyniter industry because an igniter mus~ be capable of igniting ~uel gases throughout an extended lifetime of the appliance, at voltages which at times are as low as 85% of the standard operating voltage (20.4 instead of ~.0 v) which often occur during "brownouts" or peak el~ctrical demand periods.
Natural gas ignites at about 1050C. and propane gas ignites at about 960C. When the available voltage decreases, i.e.
to 85% of the nominal voltage, an igniter temperature below that required for gas ignition could occur, particularly in older igniters in which the electrical contact has experienced severe deterioration. Thus, there is a need for an igniter which, after 100,000 cycles, does not exhibit any substantial increase in its resistance due to the electrical contact, and preferably has a low increase in total resistance, i.e. that due to both the igniter itself and the electrical connection.
U.S. Pat. No. 4,512,871 discloses an oxygen sensor with a heater in which a non-electrically conducting ceramic body 2 ~ ~i 3 ~ -.e, is screen prinked with an electrically conductive circuit which terminates in a pair of pads to which electrical contacts are made by brazing. The ceramic body is an insulator and merely functions as a physical support. Thus 5 the problem of forming an improved electrically conductive connection is not ~aced by the patent.
Accordingly, it is an object of the present invention to produce an improved ceramic igniter which will have less than about a 2~ change in contact resistance of the contacts lo after 100,000 on/off cycles and which can be reproducibly manufactured.
It is a further object to produce such an igniter having less than a about 2.5% change in contact resistance after being continuously powered at operating temperature for 2000 hours.
It is a further object to produce such an igniter from a ceramic composition comprising molybdenum disilicide, silicon carbide, or mixtures thereof as ~he conducting ceramic.
These and still further objects will be apparent from the ensuing detailed description of the invention.
SUMMARY OF THE INVENTION
Ceramic igniters are prepared by (i) forming a ceramic igniter body having a molybdenum disilicide content of at least about 20 volume percent at the points at which the electrical contacts are to be made, (ii) forming two pads of an active metal braze on the body at those points, and (iii) soldering electrical leads to said pads by means of a solder which melts at a temperature of greater than about 500C.
20ri~r,~
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a top view of a preferred igniter body with connecting leads soldered to braze pads in accordance with this invention.
S DESCRIPTION OF THE PgEFERRED EMBODIMENTS
The ceramic igniters of the present invention comprise a non-conductive ceramic in combination with an electrically conductive ceramic. The improved electrical connections to the ceramic igniters are produced by forming a braze pad on the igniters and then soldering an elec~rical wire to the braze pad. The igniters prepared with ~wo such electrical connections may be reproducibly produced commercially and furthermore exhibit less than about a 2% change in contact resistance after being subjected to 100,000 on/off cycles.
Also, the igniters exhibit less than about a 2.5% change in contact resistance after being continuously powered at 26.4 volts at elevated temperature (1275 - 1500C.) for 2000 hours. The conductive component of the ceramic is preferably comprised of molybdenum disilicide, silicon carbide, or a mixture thereof. More preferably a mixture of molybdenum disilicide (MoSi2) and silicon carbide (SiC), as disclosed in U.S. Pat. Appln. Ser. No. 258,307 o~ Washburn, filed October 14, 1988, is used. The disclosure and subject matter of Washburn is incorporated herein by reference.
The igniter preferably comprises about 40 to 70 volume percent of a nitride ceramic and about 30 to 60 volume percent MoSi2 and SiC in a volume ratio of from about 1:3 to 3:1. A more preferred igniter has a varying composition as described by Washburn and as indicated in Fisure 1 hereof.
In this case, the chemical composition of the igniter 10 is varied from a high resistive portion 12 through an intermediate portion 14 to a highly conductive portion 16.
Alternatively and even more preferably the intermediate ~ ~ r~
portion 14 i5 omitted (for ease of manufacturiny). The conductive portion is provided with the two active metal braze pads 18 and 18~ to w~ich electrical leads 20 and 20' are respec~ively soldered in accordance with this invention.
The highly resistive portion 12 of the igniter 10 is preferably comprised of about 50 to 70 volume percent nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ratio of about 1.~. The intermediake portion 14, when present, is preferably comprised of about 50 to 70 volume percent nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ratio of about 1:1.
The highly conductive portion 16 is preferably comprised of about 45 to 55 volume percent nitride ceramic and about 45 to 55 volume percent MoSi2 and SiC in a volume ratio of from about 1:1 to about 3:2~ By ~highly resistive" is meant that the section has a resistivity in the temperature range of 1000 to 1600C. of at least about o.04 ohm-cm, preferably at least about 0.07 ohm-cm. By ~highly conductive" is meant that the section has a resistivity in the temperature range of 100 to 800C. of less than about 0.005 ohm-cm, preferably less than about 0.003 ohm-cm, and most prefer~bly less than about 0.001 ohm-cm.
Suitable nitrides for use as the resistive component of the ceramic igniter include silicon nitride, aluminum nitride, boron nitride, and mixtures thereof. Preferably the nitride is aluminum nitride.
The first step to forming the electrical connections of the present invention is to produce a braze pad or area on opposite ends of the highly conductive portions of the ceramic igniter. To obtain the high degree of adhesion to the ceramic which is required, a braze which contains an active metal is utilized. A metal is considered "active"
~3~
herein if it has the ability to wet and react with the ceramic materials suf~iciently to provide a~herence thereto by iller metals contained in the braze. Examples of specific active metals include titanium, zirconium, niobium, nickel, palladium, and gold. Preferably the active metal is titanium or zirconium. In addition to the active metal, the braze contains one or more filler metals such as silver, copper, indium, tin, zincl lead, cadmium, and phosphorous.
Preferably a mixture of filler metals is used. Most preferably, the braze will comprise titaniu~ as the active metal and a mixture of copper and silver as the filler metal.
Generally, the braze will contain in weight percent about 0.1 to about 5 weight percent active metal and about 99.9 to about 95 weight percent filler metal. Suitable such brazes are commercially available under the trade name Lucanex from ~ucasMilhaupt, Inc. and Cusil from GTE Products Corporation. Specific brazes found useful herein include:
Lucanex 721 and Cusil Braze, each of which nominally contain 70.5% silver, 27.5~ copper, and 2% titanium.
- Electrical wire leads are then connected to the braze pads by a solder. The solder must be able to withstand temperatures of about 450C. during use of the igniter without degradation and also must have a low resistivity.
Generally, a solder having a melting point of greater than about 500C., preferably greater than about 600C. Suitable such solders are those which contain in weight percent about 1 to about 90% silver, about 5 to about 80% copper, about 5 to about 40% zinc, and up to about 40% of one or more metals selected from aluminum, tin, indium, phosphorous, cadmium, and nickel. Preferably, the solder will contain about 10 to 70% silver, about 10 to 70% copper, about 10 to 35~ zinc, and up to 30% of the other metals. Most preferably, the ~53~
solder will contain about 15 to 60~ silver, about 10 to 60%
copper, about 12 to 30% zinc, and up to about 30% o~ the other metals.
Suitable such solders are commercially available under the trade names Easy-Flo from Handy ~ Harmon Co. and Safety-Silv from J.W. Harris Co., Inc. A specific solder found useful herein is Easy-Flo 45 which nominally contains 45% silver, 15% copper, 16% xinc and 24% cadmium. Other specific solders which may be used include Safety-Sil~ 1200 10which nominally contains 56% silver, 22% copper, 17% zinc, and 5% tin, and Safe~y-Silv 1577 which nominally contains 25% silver, 52%.5 copper, and Z2.5 zinc.
To perfoxm the soldering of the wires to the braze pads, it has been found advantageous to apply the solder first to the metal wire. When the wire is placed on the braze pad on the igniter and then heated ~o attach it, the solder can flow from the wire to the brazed region to make the connection. This method minimizes the amount of time during which the braze is heated to above 500C, which will minimize/prevent oxidation of the braze pad by the air before it becomes coated with the solder. Oxidation is detrimental since it could prevent a solid chemical bond from forming and could result in mechanical failure and/or an electrical interface having a resistance higher than that of either the metal wire or ceramic igniter.
The practice of the present invention can be further appreciated from the following non-limiting examples and comparative examples in which all parts and percents are by weight unless otherwise specified.
30Exam~le 1 A double-legged triple composition hairpin or U-shaped ~3~
ceramic igniter as shown in Fig. 1 is prepared from ~luminum nitride, silicon carbide, an~ molybdenum disilicide in accordance with the teachinys of U.S.S.N. 258,307, Washburn.
By volume percents, the conductive portion contains 50%
aluminum ni~ride, 30% moly~den~m disilicide, and Z0% silicon carbide; the intermediate portion contains 60~ aluminum nitride, 20% molybdenum disilicide, and 20~ silicon carbide;
and the resistive portion contains 60% aluminum nitride, 13%
molybdenum disilicide, and 27~ silicon carbide.
To form a braze pad on each of the legs of the igniter, an active metal brazing paste, Lucenex 721, is brushed onto - a 0.06" x 0.25" area of each of the legs. The paste is heated by means of a refractory metal furnace under a high vacuum to a temperature of 875C. for 10 minutes to form the pads.
To adhere a conventional copper electrical wire to each of the braze pads, Easy-Flo 45 Solder (45% silver, 15%
copper, 16% zinc, and 24~ cadmium) is used. The soldering is performed using an oxy-acetylene torch as a heat-source.
A standard silver solder flux is first brushed onto the braze pad to clean the surface. Then the wire is heated and the solder introduced to the heated wire. The molten solder flows onto the wire in less than about 5 seconds. The solder-containing end of the wire is placed on the pre-fluxed, braze pad of the igniter and heated with the oxy-acetylene torch, allowing the silver solder to melt and flow onto the braze pad for about less than 5 seconds and then removed. The wire is held in place for an additional 5 seconds until the solder hardens by cooling.
To evaluate the performance of the resultant electrical connection, the igniter is subjected to the standard American Gas Association test for evaluation of 2~3~ 3~
thermoelectric devices, ANSI Test Procedure Z 21.20, 1g89, pp.lZ-13. The test entails cycling the igniter through 100,000 on/off sequences and determining the percent resistance changes of the total device and of the igniter body. The resistance chang~ due to the electrical contact is then calculated by diference.
~ he results from duplicate samples prepared as above and having a~erage initial igniter temperatures o~ 12~5 and 1293~C. respectively are:
Resistance Chanqes. %
Sample ?otal Ianiter Only contact Only A 26.8 25.6 1.2 B 21.5 20.8 0.7 The procedure of Example 1 is repeated except that the Lucanex 721 Braze is replaced with Cusil Braze which has the same nominal composition. The results from duplicate samples ha~ing average initial igniter temperatures of 1283 and 1282C. are:
Resistance Chanaes, %
Sample Total Ianiter OnlY Contact OnlY
C 20.0 18.8 1.2 D 21.0 19.5 1.5 Com~arative ~xamPle A
The procedure of Example 1 is repeated with a different solder, Realistic Electrical Solder which contains 60% tin and 40~ lead. Attempts to solder the wires to the braze pads using an oxyacetylene torch, a propane torch, and an electrically heated soldering iron were unsuccessful. The solder did not bond the wires to the braze.
~3~
Example 3 The prGcedure o~ Example 1 is repeated except that the intermediate portion o~ the ceramic i~niter is omi~ted and the igniter is evaluated in a constant~on test at 24.0 V for 2,350 hours. Four such samples are evaluated and are found to hav~ a percent contact resistance at the end of the test of 0.82%, 0 4 ~3%, 0.95% and 0~.
ExamPle 4 The procedure of Example 3 is repeated except that the solder is Safety-Silv 1577. The percentage change in contact resistance after the specified number of hours during a constant-on test for multiple samples is Resistance Chanaes~_~
Sample o 840 1800 2472 1 o 1.4 1.4 0.7 2 0 1.4 2.1 . 0.7 3 0 1.4 2.3 0.8 4 0 1.4 2.1 0.7 0 2Ø 2.1 0.7 6 0 1.4 2.2 1.5 Example 5 The procedure of Example 4 is repeated except that the solder is Safety-Silv 1200. The percentage change in contact resistance after the specified number of hours during a constant-on test for mul~iple samples is:
Resistance ChangLes %~
SamPle 0 768 153~2328 3000 1 0 0.6 0 2.1 0 2 0 0 1.42.2 0 3 0 0.6 1.42.0 0.7 4 o 0.6 1.32.1 2.2 0 0.6 0 2.1 0.7
Claims (15)
1. A ceramic igniter, comprising:
(i) a ceramic igniter body having a molybdenum disilicide content of at least about 20 volume percent at two points at which electrical contacts are to be made;
(ii) active metal braze pads on the body at each of the two electrical contact points, and (iii) electrical leads attached to said braze pads by means of a solder which melts at a temperature of greater than about 500°C.
(i) a ceramic igniter body having a molybdenum disilicide content of at least about 20 volume percent at two points at which electrical contacts are to be made;
(ii) active metal braze pads on the body at each of the two electrical contact points, and (iii) electrical leads attached to said braze pads by means of a solder which melts at a temperature of greater than about 500°C.
2. The ceramic igniter of Claim 1 wherein the igniter body comprises about 40 to 70 volume percent of a nitride ceramic and about 30 to 60 volume percent of a combination of MoSi2 and SiC in a volume ration of from about 1:3 to 3:1.
3. The ceramic igniter of Claim 1 wherein the igniter body comprises (i) a highly resistive portion containing about 50 to 70 volume percent of a nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ration of about 1:2 and (ii) a highly conductive portion containing about 50 to 70 volume percent of a nitride ceramic and about 30 to 50 volume percent MoSi2 and SiC in a volume ratio of about 1:1.
4. The ceramic igniter of Claim 2 wherein the nitride ceramic is selected from the group consisting of silicon nitride, aluminum nitride, boron nitride, and mixtures thereof.
5. The ceramic igniter of Claim 1 wherein the active metal braze pads comprise an active metal selected from the group consisting of titanium, zirconium, niobium, nickel, palladium, and gold.
6. The ceramic igniter of Claim 5 wherein the active metal braze pads further comprise at least one filler metal selected from the group consisting of silver, copper, indium, tin, zinc, lead, cadmium, and phosphorous.
7. The ceramic igniter of Claim 1 wherein the active metal braze pads comprise titanium, copper, and silver.
8. The ceramic igniter of Claim 1 wherein the solder comprises about 1 to 90% silver, about 5 to 80% copper, about 5 to 40% zinc, and up to about 40% of at least one metal selected from the group consisting of aluminum, tin, indium, phosphorous, cadmium, and nickel.
9. A method of making an electrical contact to an electrically conducting ceramic material for use at a design operating temperature which comprises (i) forming a pad of an active metal braze on the electrically conductive ceramic material and (ii) soldering an electrical lead to said braze pad by means of a solder which melts at a temperature of at least about 50°C. higher than the maximum design operating temperature of the contact.
10. The method of Claim 9 wherein the active metal braze pads comprise an active metal selected from the group consisting of titanium, zirconium, niobium, nickel, palladium, and gold.
11. The method of Claim 10 wherein the active metal braze pads further comprise at least one filler metal selected from the group consisting of silver, copper, indium, tin, zinc, lead, cadmium, and phosphorous.
12. The method of Claim 9 wherein the active metal braze pads comprise titanium, copper, and silver.
13. The method of Claim 9 wherein the design operating temperature is at least about 450°C.
14. The method of Claim 9 wherein the solder comprises about 1 to 90% silver, about 5 to 80% copper, about 5 to 40%
zinc, and up to about 40% of at least one metal selected from the group consisting of aluminum, tin, indium, phosphorous, cadmium, and nickel.
zinc, and up to about 40% of at least one metal selected from the group consisting of aluminum, tin, indium, phosphorous, cadmium, and nickel.
15. The method of Claim 9 wherein the solder is placed on the electrical lead which is then placed on the braze pad and heated.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61294790A | 1990-11-13 | 1990-11-13 | |
| US612,947 | 1990-11-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2053454A1 true CA2053454A1 (en) | 1992-05-14 |
Family
ID=24455252
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2053454 Abandoned CA2053454A1 (en) | 1990-11-13 | 1991-10-15 | Extended life ceramic igniters |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0486009A1 (en) |
| JP (1) | JPH04268111A (en) |
| CA (1) | CA2053454A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0570914A3 (en) * | 1992-05-18 | 1995-09-13 | Norton Co | Ceramic igniters and process for making same |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4325606A1 (en) * | 1993-07-30 | 1995-02-09 | Bach Wolfdietrich | Ceramic heating element and method for producing such a heating element |
| US5705261A (en) * | 1993-10-28 | 1998-01-06 | Saint-Gobain/Norton Industrial Ceramics Corporation | Active metal metallization of mini-igniters by silk screening |
| JP3230793B2 (en) * | 1995-01-24 | 2001-11-19 | 富士電機株式会社 | Ceramic heating element |
| US5804092A (en) * | 1995-05-31 | 1998-09-08 | Saint-Gobain/Norton Industrial Ceramics Corporation | Modular ceramic igniter with metallized coatings on the end portions thereof and associated terminal socket |
| US6078028A (en) | 1999-02-19 | 2000-06-20 | Saint-Gobain Industrial Ceramics, Inc. | Solderless ceramic igniter having a leadframe attachment |
| JP4733117B2 (en) * | 2004-05-28 | 2011-07-27 | サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド | Ignition system |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2992959A (en) * | 1958-02-20 | 1961-07-18 | Kanthal Ab | Production of shaped bodies from heat resistant oxidation proof materials |
| US3875476A (en) * | 1974-01-10 | 1975-04-01 | Honeywell Inc | Igniter element |
| US4486651A (en) * | 1982-01-27 | 1984-12-04 | Nippon Soken, Inc. | Ceramic heater |
| JPS6029518A (en) * | 1983-07-27 | 1985-02-14 | Hitachi Ltd | Heater for glow plug |
| JPH0311575Y2 (en) * | 1986-04-11 | 1991-03-20 |
-
1991
- 1991-10-15 CA CA 2053454 patent/CA2053454A1/en not_active Abandoned
- 1991-11-12 JP JP29594791A patent/JPH04268111A/en active Pending
- 1991-11-13 EP EP91119390A patent/EP0486009A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0570914A3 (en) * | 1992-05-18 | 1995-09-13 | Norton Co | Ceramic igniters and process for making same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04268111A (en) | 1992-09-24 |
| EP0486009A1 (en) | 1992-05-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101228396B (en) | Brazed structure, ceramic heater, and glow plug | |
| US5705261A (en) | Active metal metallization of mini-igniters by silk screening | |
| KR100326850B1 (en) | Ceramic glow plug | |
| EP0843131B1 (en) | Ceramic glow plug | |
| KR100421760B1 (en) | Solderless ceramic igniter having a leadframe attachment | |
| CZ9902645A3 (en) | Ceramic spark plug with compound head and process of glowing thereof | |
| CA2053454A1 (en) | Extended life ceramic igniters | |
| CN1185828A (en) | Modular Ceramic Igniter | |
| US5218751A (en) | Method of making a resistance ignitor for igniting gaseous fuel | |
| JP3588227B2 (en) | Ceramic heater | |
| JP3594660B2 (en) | Ceramic heater | |
| JPS5895122A (en) | Glow plug for high temperature | |
| JP2735725B2 (en) | Ceramic heating element | |
| JP2735721B2 (en) | Ceramic heating element | |
| JP3004134B2 (en) | Ceramic heating element | |
| JP3762103B2 (en) | Ceramic heater | |
| EP0007198B1 (en) | Igniter | |
| JPH07158853A (en) | Electric resistance ignition device and production thereof | |
| KR20070032668A (en) | Igniter system | |
| JPH06196252A (en) | Ceramic heating element | |
| JPH04174991A (en) | Ceramic heater | |
| MXPA01008410A (en) | Solderless ceramic igniter having a leadframe attachment | |
| JPH038074B2 (en) | ||
| JPH06241452A (en) | Ceramic heating element |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |