CA1043587A - Electrical resistor glaze composition and resistor - Google Patents
Electrical resistor glaze composition and resistorInfo
- Publication number
- CA1043587A CA1043587A CA215,683A CA215683A CA1043587A CA 1043587 A CA1043587 A CA 1043587A CA 215683 A CA215683 A CA 215683A CA 1043587 A CA1043587 A CA 1043587A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/14—Conductive material dispersed in non-conductive inorganic material
- H01B1/16—Conductive material dispersed in non-conductive inorganic material the conductive material comprising metals or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
- H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
- H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits
- H01C17/06513—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component
- H01C17/06526—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component composed of metals
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- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Non-Adjustable Resistors (AREA)
- Thermistors And Varistors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a vitreous enamel resistance material and resistors made therefrom, particu-larly to a vitreous enamel resistance material having a relatively low resistivity and low temperature coefficient of resistance and which has good antiflammability character-istics. A prior resistance material uses a mixture of a glass frit and fine particles of a conductive material. The conductive material generally includes a nobel metal which is expensive. The present invention provides an economical vitreous enamel resistance material which can be made with a low resistivity and low temperature coefficient of resistance and has good antiflammability characteristics. The vitreous enamel resistance material includes a mixture of a vitreous glass frit and fine particles of a conductor which is an alloy of nickel and chromium The conductor particles are present in the amount of 28% to 80% by weight. Up to 3% by weight of titanium and/or titanium nitride may be included in the resistance material to adjust the temperature co-efficient of resistance of the material.
The present invention relates to a vitreous enamel resistance material and resistors made therefrom, particu-larly to a vitreous enamel resistance material having a relatively low resistivity and low temperature coefficient of resistance and which has good antiflammability character-istics. A prior resistance material uses a mixture of a glass frit and fine particles of a conductive material. The conductive material generally includes a nobel metal which is expensive. The present invention provides an economical vitreous enamel resistance material which can be made with a low resistivity and low temperature coefficient of resistance and has good antiflammability characteristics. The vitreous enamel resistance material includes a mixture of a vitreous glass frit and fine particles of a conductor which is an alloy of nickel and chromium The conductor particles are present in the amount of 28% to 80% by weight. Up to 3% by weight of titanium and/or titanium nitride may be included in the resistance material to adjust the temperature co-efficient of resistance of the material.
Description
The present invention relates to a vltreous enamel re~istance material and resistors made thererrom. More particularly, the present invention relates to a vitreous enamel resistance material whlch can be made to have a rela-tively low resistivity and low temperature coefflcient of resistance and which has good antiflammability character-istics.
A type of resistance material which has come into substantial use is a vitreous enamel resistance material which comprlses a mixture of a glass frit and fine parti-cles of a conductive material. For many uses of this type of resistance material it is desirable to have such a re-sistance material which can have a low resistivity, e.g., between 2 and 20 ohms per square, and a low temperature co-efficient of reslstance, e.g., less than 50 parts per mill-ion per C (PPM/C). Although vitreous enamel resistance materials having these characteristics have been made, theg generally include a noble metal, such as gold, palladium, silver, etc., as the conductive material. Thus, such materials are relatively expensive. Therefore, it would be desirable to have a vitreous enamel resistance material which can be made with these characteristics but which does not include a noble metal so as to be less expensive. Also, another characteristic often desired for such resistance materials is good antiflammability, i.e., it will not readily burn when sub~ected to an overload.
It is therefore an obJect of the present invention to provide a novel vitreous enamel resistance material which can be made with a low resistivity and low temperature co-efficient of resistance and has good antiflammabllitycharacteristics.
It is another object of the present invention to provide a vitreous enamel resistance material which includes ~ ?
a mlxture Or a glass rrlt and ~lne particles o~ an alloy o~ nickel and chrom~um.
It iB Btill another obJect Or th~ present lnvention to provlde a vitreou~ enamel reslstance materlal Whlch include8 a mlxture Or a glaB8 rrit and rine partlcle~ Or an alloy o~ nlckel and chromium to whlch 18 added a ~mall amount Or tltanium and/or tltaniu~ nltride to adJu~t the temperature coerrlclent o~ re 9 i8 tance o~ the res i8 tance materlal.
Other obJect3 ~ill appear herelnarter.
The lnvention accordlngly comprl8e9 a oompositlon of matter possesslng the characteristlcs, propertiesJ and the relatlon of constltuent8 whlch ~111 be exempll~led ln the composltion herelnarter de8cribed, and the BCOpe Or the ln~entlon ~111 be lndlcat~d ln tho clalm~.
More particularly, there is provided a vitreous enamel resistor composition adapted to ~e applted to and fired on a ceramic body to form electrical resistors comprising a mixture of a glass frit and finely divided particles of an alloy of nickel and chromium, the particles of the alloy being present in the mixture in the amount of approximately 28 to 80% by weight, and said alloy containing approximately 75 to 80~ by weight of nickel and approx-imately 20~ by weight of chromium.
There is also provided an electrical resistor having a resistivity in the range of approximately 2 to 20 ohms per square, comprising a nonconductive ceramic body, a resistive film of glass on a surface of the body, and fine particles of an alloy containing approximately 75 to 80%
by weight of nickel and approximately 20% by weight of chromium embedded within and dispersed throughout the glass film, the alloy being present in the resistive film in the amount of approximately 28 to 80% by weight.
Il ~ ~ -2-B`
l(J4 ~rD~7 The dra~lng lo a oros~-sectlonal vle~, on a hlghly exaggerated s¢ale, Or a reslstor produced ~Ith the resls-tance materlal Or tbe present lnvontlon.
In ~eneral, the ~itroou~ enamel reslstance materlal Or the present inventlon oompri~es a mixture o~ glass rrlt and rlne particles Or an alloy Or nlckel and chromium. A
prererred alloy iB 75% ntckel, 20% chromium, 2.5% copper and 2.5% alumlnum, although other allo~ o~ nick~l snd ¢hro-mlum are usable. me cond~ctlve partlcles Or the alloy are present inth~ ml~ture ln the amount o~ 28% to 80% by ~eight.
In additlon, thc reststanoo materlai may ~nclude up to 3~
by ~eight Or rlne partlcle~ 20 Or tltanlum and/or tltanlum nltride tD adJust the temperature ¢oerrlcl~nt Or res~stance o~ the materla~. ffle add~tlon Or tltanlum to the ml~ture shl~t~ tho temperatur~ coerrlcient o~ resl~tance negatlve ~hile the addltlon o~ tltanium nltrld~ shirto the tempera-turo coerrlclent Or recl~tance po~ltive.
me gla~ rrlt used in the re~i~tance materlal Or , .
~, ' -2a-,r ~ .
the present lnvention may be o~ any well known compositlon which ha~ a softening temperature below the meltlng temper-ature of the conductive particles. The glass frits most preferably used are the borosillcate frits, such as lead borosilicate ~rit, bismuth, cadmium, barium, calcium or other alkaline earth borosilicate frlts. The preparatlon of such glass frits is well known and consists, for example, in melting together the constituents of the glas~ ln the form of the oxides of the constituents, and pouring such molten composition into water to form the frit. The batch in-gredients may, of course, be any compound that wlll yleld the desired oxides under the usual conditlons of frit pro-duction. For example, boric oxide will be obtained from boric acid, silicon dloxide will be produced from flint, barium oxide will be produced from barium carbonate, etc.
The glass is preferably milled in a ball-mill with water to reduce the particle size of the frit and to obtain a frit with particles of substantially uniform size.
The particles of the alloy of nickel and chromlum c~n be made by atomizing molten alloy into -325 mesh powder.
The titanium and titanium nitride particles used to ad~ust the temperature coefficient of reslstance are also -325 mesh powder of these materials.
To make the resistance material of the present in-vention, a mixture of 70~ to 80% of the conductlve parti-cles and 20~ to 30~ of the glass ~rit are ball milled together to reduce the particles siæe of the conductive partlcles to a Fisher Sub Sieve number (~SS) of about 1.
The ball milling may be done wet or dry, but lt is prefer-able to do it wet with butyl carbitol acetate. Ball mill-lng the conductive particles with some glass frit increases the grinding rate and reduces contamination. Additional glass frit is then added to the ball milled mixture to achieve the desired proportions of the conductlve parti-oles and gla~ frit. The mixture is then wet milled with butyl carbitol acetate at a viscosity which is preferably of 1-3 poise to achieve a uniform mixture. The mixture i8 then ad~usted to the proper viscosity for the desired manner of applying the resistance materlal to a substrate by either adding or removing the llquid medlum of the mater-ial. For example, to apply the resistance materlal by dlpping, the material is preferably adjusted to a viscoslty of 1-2 poise. However, to apply the reslstance materlal by screen printlng, the milling vehicle is evaporated, and the mixture is mixed with a suitable organic binder on a roll mill.
To make a resistor with the resistance material of the present invention, the reslstance material is applied to a uniform thickness on the surface of a substrate. The substrate may be a body of any material which can withstand the firing temperature of the resistance material composi-tion. The substrate is generally a body of a ceramic, such as glass, p~rcelain, refractory, barium titinate, or the like. The resistance material may be applied on the sub-strate by brushing, dlpplng, spraying or screen stencil application. The substrate with the resistance material ¢oatlng ls then fired in a conventional furnace at a tem-perature at whlch the glass frit becomes molten, typically between 800C and 1100C. For resistance materials of the present invention, it has been found preferable to fire the coated substrate in an ln~rt atmosphere, such as argon, helium, nitrogen to achleve a reslstor of better stablllty.
30- When the coated substrate is cooled, the vitreous enamel hardens to bond the resistance material to the substrate.
As shown ln the drawlng, the resultant resistor of the present invention is generally designated as 10. Re-sistor 10 compri~es the ceramio sub8trate 12 havlng a layer14 of the resistance material of the present inventlon coated and ~lxed thereon. The resistance material layer 14 comprlses the glass 16 and the finely divlded partlcles 18 of the alloy of nickel and chromium embedded within and dispersed throughout the glass 16. Particles 20 of tltanium and/or titanium nltride, may also be embedded wlthin and dispersed throughout the glass 16.
The following examples are given to illustrate certain preferred details of the invention, it being under-stood that the detalls o~ the examples are not to be taken as in any way limiting the lnvention thereto.
EXAMPLE I
A resiætance materlal of the present invention was made by ball milling together a mixture of 79~ by weight of an alloy of 75~ nickel, 20% chromium, 2.5~ copper and 2~5~
aluminum of a particle size of -325 mesh, and 21% by welght of an alkaline earth borosilicate (52~ barium oxide, 20 baron oxide, 20% silicon dioxide, 4~ aluminum oxide and 4 titanium oxide) frit with 26 parts by weight of butyl car-bitol acetate to reduce the particle size of the mixture to l-2FSS. Additional amounts of the glass ~rit were added to various portions of the mixture to form resistance mater-ials having the compositions shown in Table I, and butyl carbitol acetate was added to each of the compositions to provide a milling viscosity of 0.5 to 2 poise. The compo-sitions were ea¢h ball milled for 72 hours and then ad~usted to a 1 to 2 poise dipplng viscosity.
Alumina rods 0.095 inches in diameter were dipped in each of the compositions, dried and fired at 1000C in nitrogen on a 30 minute cycle. The fired rods were sec-tioned into 0.35 inch long pieces. A silver coating was applied to both end~ of each section and a capped lead forced over the silver ooating. The resistanoe values and temperature coefflolent o~ resistance of these reslstors are shown in Table I.
TABLE I
.
l 2 ~ 4 5 ~ 7 Gla~s ~rit (wt. %) 71.6 63.6 56.6 50.2 38.4 28.6 22.8 Alloy partlcles (wt. ~ 27.7 35.2 42.1 48.4 59.5 69.o 76.6 Mill contaminates (wt. %) 0.8 l.0 1.2 1.5 2.1 2.4 0.7 10 Resistance (ohms/square) 17.0 7.4 4.8 2.2 1.8 2.4 3.o Temperature coeff.
of Re~istance(ppM/oc) +25C to ~150C 98 91 88 80 80 71 49 +25c to -55c 93 90 92 88 85 77 42 EXAMPLE II
A reslstance material was made ln the same manner as described in Example I with the resistance material having a final composition of 50.2% by weight of the alloy, 48.4%
by welght of the glass frit and 1.5~ by weight of mill con-taminates. Reslstors were made with this composition and in the same manner as described in Example I, except that different groups o~ the resistors were fired at dif~erent temperatures as shown in Table II. The resistance values and temperature coe~icient of resistance o~ these re~is-tors are shown in Table II. Thls shows thee~fect of the firing temperature on the resistance value and temperature coef~.cient of resistance achieved.
TABLE II
_ . . .
Flring temperature (C) 825 950 1000 1100 cycle time (Hrs ) l.0 1.0 0.5 0.5 `f TABLE II (Con't) Reslstance (ohms/square) 23 16 2.2 3.2 Temperature Coe~ficient o~ Resistance (PPM/C
+25C to +150C 73 102 80 72 +25c to -55C 45 105 88 62 EXAMPLE III
Resista~ce materials were made in the manner descrlbed in Example I except that titanium and/or titanium nitride were added to the varlous compositions in the amounts shown in Table III. Resistoræ were made from the~e compo-sitlons in the manner deæcribed in Example I. me resis-tance valueæ and temperature coefficientæ of reæistance of theæe reælstors are shown ln Table III. Thls shows the effect of adding the tltanlum and/or titanium nitride.
TABLE III
-Glass frit (wt, O 57 56.1 55.5 54.5 49.3 49.1 49.0 20 Alloy partlcles wt. %) 42 40.0 40.1 37.9 43.4 43.3 43.1 Titanium (wt. %) 0 1.2 1.4 2.9 2.7 2.0 o Titanium nitride (wt. %) - 0 0 0 0 0 o.8 3.2 Mill contaminates (wt. O 1 2.6 2.8 4.7 4.7 4.8 4.7 Resistance (ohm/square~ 5.0: ll .o 8.o 6.o lo .o 5.0 lo .o Temperature coe~f.
o~ Resistance (PPM/C) +25c to +150C 88 26 9 -106 -217 29 203 +25C to -55c 92 17 11 -146 -217 32 201 p ~ 4d EXAMPLE IV
Resistance materials were made in the manner de-scribed in Example I except that the alkaline earth ~rit shown in Table IV was u~ed and titanium was added to the glaze composition which is shown in Table V. A group of reslstors made wlth this resistance material was tested for flammability in the following manner: The resistors each of which had a resistance of 39 ohms and a rating of 3 watts, were sub~ected respectively to 4x, 8x, 16x and 32x rated power. A resistor was acceptable if it opened with-out flaming or i~ it flamed with a flame having a maximum height of one inch, and lasting less than one second, and did not eJect material capable of startlng a fire. Each of the resistors tested passed the flammability test with-~; out producing a flame.
TABIE IV
Weight Percentage Magnesium oxide (MgO) 10 Calclum floride (CaF2) Calcium oxide (CaO) 2 Baron oxide (B203) 28 Aluminum oxide (A12Q3) 14 - Sillcon dioxide (Sio2i 42 TABLE V
Glass frit ~wt. %) 41 Alloy particles (wt. ~) 59 Titanium (wt. ~) 0.2 Resistance 30 (Ohm/square) 2.5 Temperature coe~f.
of Resistance (PPM/C) +25C to +105C ~18 +25C to -55C +25 EXAMPIE V
- - -A resistance material was made in the same manner as described in Example I except that the alloy was 80%
nickel and 20~ chromium and had a final composition of 50%
by weight o~ the alloy and 50% by weight of the glasa frit.
Resistors were made with this composition in the same manner as descrlbed in Example I except that the resistors were fired at 1025C on a 30 minute cycle. The resistors had a resistance value of 1.2 ohms per square and temperature co-efficient of resistance values of 98 PPM/C for from ~25Cto ~150C and 95 PPM/C for from ~25C to -55C.
The present invention may be embodied in other specific forms without departing from the spirit or essen-tial attributes thereof, and, accordingly, reference should be made to the appending claims, rather than to the fore-going specifications as indicating the scope of the inven-tion.
_g_
A type of resistance material which has come into substantial use is a vitreous enamel resistance material which comprlses a mixture of a glass frit and fine parti-cles of a conductive material. For many uses of this type of resistance material it is desirable to have such a re-sistance material which can have a low resistivity, e.g., between 2 and 20 ohms per square, and a low temperature co-efficient of reslstance, e.g., less than 50 parts per mill-ion per C (PPM/C). Although vitreous enamel resistance materials having these characteristics have been made, theg generally include a noble metal, such as gold, palladium, silver, etc., as the conductive material. Thus, such materials are relatively expensive. Therefore, it would be desirable to have a vitreous enamel resistance material which can be made with these characteristics but which does not include a noble metal so as to be less expensive. Also, another characteristic often desired for such resistance materials is good antiflammability, i.e., it will not readily burn when sub~ected to an overload.
It is therefore an obJect of the present invention to provide a novel vitreous enamel resistance material which can be made with a low resistivity and low temperature co-efficient of resistance and has good antiflammabllitycharacteristics.
It is another object of the present invention to provide a vitreous enamel resistance material which includes ~ ?
a mlxture Or a glass rrlt and ~lne particles o~ an alloy o~ nickel and chrom~um.
It iB Btill another obJect Or th~ present lnvention to provlde a vitreou~ enamel reslstance materlal Whlch include8 a mlxture Or a glaB8 rrit and rine partlcle~ Or an alloy o~ nlckel and chromium to whlch 18 added a ~mall amount Or tltanium and/or tltaniu~ nltride to adJu~t the temperature coerrlclent o~ re 9 i8 tance o~ the res i8 tance materlal.
Other obJect3 ~ill appear herelnarter.
The lnvention accordlngly comprl8e9 a oompositlon of matter possesslng the characteristlcs, propertiesJ and the relatlon of constltuent8 whlch ~111 be exempll~led ln the composltion herelnarter de8cribed, and the BCOpe Or the ln~entlon ~111 be lndlcat~d ln tho clalm~.
More particularly, there is provided a vitreous enamel resistor composition adapted to ~e applted to and fired on a ceramic body to form electrical resistors comprising a mixture of a glass frit and finely divided particles of an alloy of nickel and chromium, the particles of the alloy being present in the mixture in the amount of approximately 28 to 80% by weight, and said alloy containing approximately 75 to 80~ by weight of nickel and approx-imately 20~ by weight of chromium.
There is also provided an electrical resistor having a resistivity in the range of approximately 2 to 20 ohms per square, comprising a nonconductive ceramic body, a resistive film of glass on a surface of the body, and fine particles of an alloy containing approximately 75 to 80%
by weight of nickel and approximately 20% by weight of chromium embedded within and dispersed throughout the glass film, the alloy being present in the resistive film in the amount of approximately 28 to 80% by weight.
Il ~ ~ -2-B`
l(J4 ~rD~7 The dra~lng lo a oros~-sectlonal vle~, on a hlghly exaggerated s¢ale, Or a reslstor produced ~Ith the resls-tance materlal Or tbe present lnvontlon.
In ~eneral, the ~itroou~ enamel reslstance materlal Or the present inventlon oompri~es a mixture o~ glass rrlt and rlne particles Or an alloy Or nlckel and chromium. A
prererred alloy iB 75% ntckel, 20% chromium, 2.5% copper and 2.5% alumlnum, although other allo~ o~ nick~l snd ¢hro-mlum are usable. me cond~ctlve partlcles Or the alloy are present inth~ ml~ture ln the amount o~ 28% to 80% by ~eight.
In additlon, thc reststanoo materlai may ~nclude up to 3~
by ~eight Or rlne partlcle~ 20 Or tltanlum and/or tltanlum nltride tD adJust the temperature ¢oerrlcl~nt Or res~stance o~ the materla~. ffle add~tlon Or tltanlum to the ml~ture shl~t~ tho temperatur~ coerrlcient o~ resl~tance negatlve ~hile the addltlon o~ tltanium nltrld~ shirto the tempera-turo coerrlclent Or recl~tance po~ltive.
me gla~ rrlt used in the re~i~tance materlal Or , .
~, ' -2a-,r ~ .
the present lnvention may be o~ any well known compositlon which ha~ a softening temperature below the meltlng temper-ature of the conductive particles. The glass frits most preferably used are the borosillcate frits, such as lead borosilicate ~rit, bismuth, cadmium, barium, calcium or other alkaline earth borosilicate frlts. The preparatlon of such glass frits is well known and consists, for example, in melting together the constituents of the glas~ ln the form of the oxides of the constituents, and pouring such molten composition into water to form the frit. The batch in-gredients may, of course, be any compound that wlll yleld the desired oxides under the usual conditlons of frit pro-duction. For example, boric oxide will be obtained from boric acid, silicon dloxide will be produced from flint, barium oxide will be produced from barium carbonate, etc.
The glass is preferably milled in a ball-mill with water to reduce the particle size of the frit and to obtain a frit with particles of substantially uniform size.
The particles of the alloy of nickel and chromlum c~n be made by atomizing molten alloy into -325 mesh powder.
The titanium and titanium nitride particles used to ad~ust the temperature coefficient of reslstance are also -325 mesh powder of these materials.
To make the resistance material of the present in-vention, a mixture of 70~ to 80% of the conductlve parti-cles and 20~ to 30~ of the glass ~rit are ball milled together to reduce the particles siæe of the conductive partlcles to a Fisher Sub Sieve number (~SS) of about 1.
The ball milling may be done wet or dry, but lt is prefer-able to do it wet with butyl carbitol acetate. Ball mill-lng the conductive particles with some glass frit increases the grinding rate and reduces contamination. Additional glass frit is then added to the ball milled mixture to achieve the desired proportions of the conductlve parti-oles and gla~ frit. The mixture is then wet milled with butyl carbitol acetate at a viscosity which is preferably of 1-3 poise to achieve a uniform mixture. The mixture i8 then ad~usted to the proper viscosity for the desired manner of applying the resistance materlal to a substrate by either adding or removing the llquid medlum of the mater-ial. For example, to apply the resistance materlal by dlpping, the material is preferably adjusted to a viscoslty of 1-2 poise. However, to apply the reslstance materlal by screen printlng, the milling vehicle is evaporated, and the mixture is mixed with a suitable organic binder on a roll mill.
To make a resistor with the resistance material of the present invention, the reslstance material is applied to a uniform thickness on the surface of a substrate. The substrate may be a body of any material which can withstand the firing temperature of the resistance material composi-tion. The substrate is generally a body of a ceramic, such as glass, p~rcelain, refractory, barium titinate, or the like. The resistance material may be applied on the sub-strate by brushing, dlpplng, spraying or screen stencil application. The substrate with the resistance material ¢oatlng ls then fired in a conventional furnace at a tem-perature at whlch the glass frit becomes molten, typically between 800C and 1100C. For resistance materials of the present invention, it has been found preferable to fire the coated substrate in an ln~rt atmosphere, such as argon, helium, nitrogen to achleve a reslstor of better stablllty.
30- When the coated substrate is cooled, the vitreous enamel hardens to bond the resistance material to the substrate.
As shown ln the drawlng, the resultant resistor of the present invention is generally designated as 10. Re-sistor 10 compri~es the ceramio sub8trate 12 havlng a layer14 of the resistance material of the present inventlon coated and ~lxed thereon. The resistance material layer 14 comprlses the glass 16 and the finely divlded partlcles 18 of the alloy of nickel and chromium embedded within and dispersed throughout the glass 16. Particles 20 of tltanium and/or titanium nltride, may also be embedded wlthin and dispersed throughout the glass 16.
The following examples are given to illustrate certain preferred details of the invention, it being under-stood that the detalls o~ the examples are not to be taken as in any way limiting the lnvention thereto.
EXAMPLE I
A resiætance materlal of the present invention was made by ball milling together a mixture of 79~ by weight of an alloy of 75~ nickel, 20% chromium, 2.5~ copper and 2~5~
aluminum of a particle size of -325 mesh, and 21% by welght of an alkaline earth borosilicate (52~ barium oxide, 20 baron oxide, 20% silicon dioxide, 4~ aluminum oxide and 4 titanium oxide) frit with 26 parts by weight of butyl car-bitol acetate to reduce the particle size of the mixture to l-2FSS. Additional amounts of the glass ~rit were added to various portions of the mixture to form resistance mater-ials having the compositions shown in Table I, and butyl carbitol acetate was added to each of the compositions to provide a milling viscosity of 0.5 to 2 poise. The compo-sitions were ea¢h ball milled for 72 hours and then ad~usted to a 1 to 2 poise dipplng viscosity.
Alumina rods 0.095 inches in diameter were dipped in each of the compositions, dried and fired at 1000C in nitrogen on a 30 minute cycle. The fired rods were sec-tioned into 0.35 inch long pieces. A silver coating was applied to both end~ of each section and a capped lead forced over the silver ooating. The resistanoe values and temperature coefflolent o~ resistance of these reslstors are shown in Table I.
TABLE I
.
l 2 ~ 4 5 ~ 7 Gla~s ~rit (wt. %) 71.6 63.6 56.6 50.2 38.4 28.6 22.8 Alloy partlcles (wt. ~ 27.7 35.2 42.1 48.4 59.5 69.o 76.6 Mill contaminates (wt. %) 0.8 l.0 1.2 1.5 2.1 2.4 0.7 10 Resistance (ohms/square) 17.0 7.4 4.8 2.2 1.8 2.4 3.o Temperature coeff.
of Re~istance(ppM/oc) +25C to ~150C 98 91 88 80 80 71 49 +25c to -55c 93 90 92 88 85 77 42 EXAMPLE II
A reslstance material was made ln the same manner as described in Example I with the resistance material having a final composition of 50.2% by weight of the alloy, 48.4%
by welght of the glass frit and 1.5~ by weight of mill con-taminates. Reslstors were made with this composition and in the same manner as described in Example I, except that different groups o~ the resistors were fired at dif~erent temperatures as shown in Table II. The resistance values and temperature coe~icient of resistance o~ these re~is-tors are shown in Table II. Thls shows thee~fect of the firing temperature on the resistance value and temperature coef~.cient of resistance achieved.
TABLE II
_ . . .
Flring temperature (C) 825 950 1000 1100 cycle time (Hrs ) l.0 1.0 0.5 0.5 `f TABLE II (Con't) Reslstance (ohms/square) 23 16 2.2 3.2 Temperature Coe~ficient o~ Resistance (PPM/C
+25C to +150C 73 102 80 72 +25c to -55C 45 105 88 62 EXAMPLE III
Resista~ce materials were made in the manner descrlbed in Example I except that titanium and/or titanium nitride were added to the varlous compositions in the amounts shown in Table III. Resistoræ were made from the~e compo-sitlons in the manner deæcribed in Example I. me resis-tance valueæ and temperature coefficientæ of reæistance of theæe reælstors are shown ln Table III. Thls shows the effect of adding the tltanlum and/or titanium nitride.
TABLE III
-Glass frit (wt, O 57 56.1 55.5 54.5 49.3 49.1 49.0 20 Alloy partlcles wt. %) 42 40.0 40.1 37.9 43.4 43.3 43.1 Titanium (wt. %) 0 1.2 1.4 2.9 2.7 2.0 o Titanium nitride (wt. %) - 0 0 0 0 0 o.8 3.2 Mill contaminates (wt. O 1 2.6 2.8 4.7 4.7 4.8 4.7 Resistance (ohm/square~ 5.0: ll .o 8.o 6.o lo .o 5.0 lo .o Temperature coe~f.
o~ Resistance (PPM/C) +25c to +150C 88 26 9 -106 -217 29 203 +25C to -55c 92 17 11 -146 -217 32 201 p ~ 4d EXAMPLE IV
Resistance materials were made in the manner de-scribed in Example I except that the alkaline earth ~rit shown in Table IV was u~ed and titanium was added to the glaze composition which is shown in Table V. A group of reslstors made wlth this resistance material was tested for flammability in the following manner: The resistors each of which had a resistance of 39 ohms and a rating of 3 watts, were sub~ected respectively to 4x, 8x, 16x and 32x rated power. A resistor was acceptable if it opened with-out flaming or i~ it flamed with a flame having a maximum height of one inch, and lasting less than one second, and did not eJect material capable of startlng a fire. Each of the resistors tested passed the flammability test with-~; out producing a flame.
TABIE IV
Weight Percentage Magnesium oxide (MgO) 10 Calclum floride (CaF2) Calcium oxide (CaO) 2 Baron oxide (B203) 28 Aluminum oxide (A12Q3) 14 - Sillcon dioxide (Sio2i 42 TABLE V
Glass frit ~wt. %) 41 Alloy particles (wt. ~) 59 Titanium (wt. ~) 0.2 Resistance 30 (Ohm/square) 2.5 Temperature coe~f.
of Resistance (PPM/C) +25C to +105C ~18 +25C to -55C +25 EXAMPIE V
- - -A resistance material was made in the same manner as described in Example I except that the alloy was 80%
nickel and 20~ chromium and had a final composition of 50%
by weight o~ the alloy and 50% by weight of the glasa frit.
Resistors were made with this composition in the same manner as descrlbed in Example I except that the resistors were fired at 1025C on a 30 minute cycle. The resistors had a resistance value of 1.2 ohms per square and temperature co-efficient of resistance values of 98 PPM/C for from ~25Cto ~150C and 95 PPM/C for from ~25C to -55C.
The present invention may be embodied in other specific forms without departing from the spirit or essen-tial attributes thereof, and, accordingly, reference should be made to the appending claims, rather than to the fore-going specifications as indicating the scope of the inven-tion.
_g_
Claims (12)
OR PRIVILEGE IS CLAIMED, ARE DEFINED AS FOLLOWS:
1. A vitreous enamel resistor composition adapted to be applied to and fired on a ceramic body to form electrical resistors comprising a mixture of a glass frit and finely divided particles of an alloy of nickel and chromium, the particles of the alloy being present in the mixture in the amount of approximately 28 to 80% by weight, and said alloy containing approximately 75 to 80% by weight of nickel and approximately 20% by weight of chromium.
2. A vitreous enamel resistance material in accordance with claim 1 in which the alloy includes approximately 75%
by weight of nickel and 20% by weight of chromium.
by weight of nickel and 20% by weight of chromium.
3. A vitreous enamel resistor composition in accordance with claim 2 in which the alloy also includes about 2.5% by weight of copper and about 2.5% by weight of aluminum.
$. A vitreous enamel resistor composition in accordance with claim 1 in which the mixture also includes up to about 3%
by weight of titanium particles.
by weight of titanium particles.
5. A vitreous enamel resistor composition in accordance with claim 11 in which the mixture also includes up to about 3%
by weight of particles of titanium nitride.
by weight of particles of titanium nitride.
6. A vitreous enamel resistor composition in accordance with claim 1 in which the mixture also includes a total weight of up to about 3% of particles of both titanium and titanium nitride.
7. An electrical resistor having a resistivity in the range of approximately 2 to 20 ohms per square, compris-ing a nonconductive ceramic body, a resistive film of glass on a surface of the body, and fine particles of an alloy containing approximately 75 to 80% by weight of nickel and approximately 20% by weight of chromium embedded within and dispersed throughout the glass film, the alloy being present in the resistive film in the amount of approximately 28 to 80%
by weight.
by weight.
8. An electrical resistor in accordance with claim 7 wherein the alloy includes approximately 75% by weight of nickel.
9. An electrical resistor in accordance with claim 8 wherein the alloy also includes about 2.5% by weight of copper and about 2.5% by weight of aluminum.
10. An electrical resistor in accordance with claim 7 including up to about 3% by weight of fine particles of titanium embedded in and dispersed throughout the glass film.
11. An electrical resistor in accordance with claim 7 including up to about 3% by weight of fine particles of titanium nitride embedded in and dispersed throughout the glass film.
12. An electrical resistor in accordance with claim 7 including a total weight of up to about 3% of fine particles of both titanium and titanium nitride embedded in and dispersed throughout the glass film.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US49123874A | 1974-07-24 | 1974-07-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1043587A true CA1043587A (en) | 1978-12-05 |
Family
ID=23951345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,683A Expired CA1043587A (en) | 1974-07-24 | 1974-12-09 | Electrical resistor glaze composition and resistor |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5115192A (en) |
| CA (1) | CA1043587A (en) |
| DE (1) | DE2455395C3 (en) |
| DK (1) | DK145150C (en) |
| FR (1) | FR2280181A1 (en) |
| GB (1) | GB1447579A (en) |
| IT (1) | IT1026866B (en) |
| NL (1) | NL178919C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4100524A (en) * | 1976-05-06 | 1978-07-11 | Gould Inc. | Electrical transducer and method of making |
| US4645621A (en) * | 1984-12-17 | 1987-02-24 | E. I. Du Pont De Nemours And Company | Resistor compositions |
| ITFI20050142A1 (en) * | 2005-06-23 | 2006-12-24 | Colorobbia Italiana Spa | MATERIALS FOR THE COVERING OF CERAMIC BODIES, PROCESSED FOR THEIR PREPARATION THEIR USE AND THE CERAMIC ARTICLES THAT INCLUDE THEM |
| CN104711455B (en) * | 2013-12-16 | 2017-08-01 | 深南电路有限公司 | Film resistor material, film resistor and preparation method thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB701184A (en) * | 1950-11-07 | 1953-12-16 | Gen Motors Corp | Improvements in or relating to ceramic bonded conductors |
| US3309643A (en) * | 1964-01-02 | 1967-03-14 | Massachusetts Inst Technology | Electric heating element |
| US3441516A (en) * | 1966-04-21 | 1969-04-29 | Trw Inc | Vitreous enamel resistor composition and resistor made therefrom |
| US3484284A (en) * | 1967-08-15 | 1969-12-16 | Corning Glass Works | Electroconductive composition and method |
| US3523357A (en) * | 1967-12-14 | 1970-08-11 | Sylvania Electric Prod | Electrical contact material and method of making and utilizing the same |
| AT331923B (en) * | 1971-12-02 | 1976-08-25 | Bruss G Univ Im V I Leni | METAL-CERAMIC GROUND RESISTANCE |
-
1974
- 1974-11-13 GB GB4907374A patent/GB1447579A/en not_active Expired
- 1974-11-22 DE DE19742455395 patent/DE2455395C3/en not_active Expired
- 1974-12-05 NL NL7415838A patent/NL178919C/en not_active IP Right Cessation
- 1974-12-06 FR FR7440145A patent/FR2280181A1/en active Granted
- 1974-12-09 DK DK639474A patent/DK145150C/en not_active IP Right Cessation
- 1974-12-09 IT IT3029474A patent/IT1026866B/en active
- 1974-12-09 CA CA215,683A patent/CA1043587A/en not_active Expired
- 1974-12-09 JP JP49141460A patent/JPS5115192A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2280181B1 (en) | 1978-03-24 |
| NL7415838A (en) | 1976-01-27 |
| DE2455395A1 (en) | 1976-02-05 |
| DE2455395B2 (en) | 1980-09-25 |
| IT1026866B (en) | 1978-10-20 |
| DE2455395C3 (en) | 1981-06-25 |
| DK639474A (en) | 1976-01-25 |
| NL178919C (en) | 1986-06-02 |
| FR2280181A1 (en) | 1976-02-20 |
| DK145150B (en) | 1982-09-13 |
| DK145150C (en) | 1983-02-14 |
| JPS5725962B2 (en) | 1982-06-02 |
| AU7587074A (en) | 1976-06-03 |
| JPS5115192A (en) | 1976-02-06 |
| GB1447579A (en) | 1976-08-25 |
| NL178919B (en) | 1986-01-02 |
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