CA2045683A1 - Composite solder article - Google Patents
Composite solder articleInfo
- Publication number
- CA2045683A1 CA2045683A1 CA002045683A CA2045683A CA2045683A1 CA 2045683 A1 CA2045683 A1 CA 2045683A1 CA 002045683 A CA002045683 A CA 002045683A CA 2045683 A CA2045683 A CA 2045683A CA 2045683 A1 CA2045683 A1 CA 2045683A1
- Authority
- CA
- Canada
- Prior art keywords
- solder
- article
- temperature control
- control component
- base 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3457—Solder materials or compositions; Methods of application thereof
- H05K3/3478—Applying solder preforms; Transferring prefabricated solder patterns
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
A composite solder article comprises: (a) a quantity of a base solder which comprises a non-eutectic alloy; and (b) a temperature control component comprising one or more metals and having a melting point that is higher than the solidus temperature of the non-eutectic alloy, the relative quantities and compositions of the two components being such that when the base solder and the temperature control component have been fused together the resulting solder alloy has a smaller solidus/liquidus temperature difference than the base solder. Preferably the temperature control component is formed from a pure metal that is present in the base solder and especially in such an amount that the overall composition is in the region of the eutectic point. The article may be used for forming solder connections to standard electrical conductors and can exhibit a reduced tendency to flow or ''wick'' along the conductor.
Description
W090/~25~ 2 ~ 3PCT/GB90/002~
, COMPCSI~- SOLD~R ARTI~'~
-This invention relates ;o solder and n particular to so-called "soft solder", ~hat ~s tO say, solde-normaliy containin~ :.n -nd/or `eaà and bavin~ _ relat.~ely l~w meit n~ Doint, -.5. iess :han ~oor, as distinct from hard solder used for Drazing. -Solder has been used .or many ye2rs for the protection of strong, high quality electrical and mech-anical connections. Recently electrical connector devices have been made in which a quantity of solder is located within a dimensionally heat-recoverable article, usually in the form of a sleeve, optionally together with one or more f~sible plastics inserts for sealin~ he connection from ngress of water. The article may be placed over he objects to be connected and may then be heated to cause the solder to fuse and form ~ connection between the objects and to cause the article to recover about the objects and provide electrical in~ulation for ~he connection. These articleq are described for example in US patent specifications Nos. 3,243,211, 4,282,396 and 4,283,~96 and in ~ritish patent specification No. 1,470,049, ~he disclo~ures of which are incorporated herein by reference, and are sold by Raychem Corporation, Menlo Park, alifornia under the trade name "Solder Sleeve"
and others.
-,, -, . . . . .
. .
, . . . . . .
.. . .
I l,i A .~3 ~.1 0 / U ti ~ ~ , o 8 ~,larch 1~108 D3 91 In International Patent Application No. W088/09068 it has been proposed to employ a composite solder insert in such devices, the composite solder insert comprising a relatively low melting point solder and a relative high melting point solder, so that, during installation of the device, the device will be heated until the relatively high melting point solder has melted, thereby ensuring that the relatively low melting point solder has received sufficient heat to cause it to melt and flow.
Although such articles function well in most instances, it has been observed that in certain cases where the device is employed with highly solder receptive substrates such as with silver coated wires, so-called "wicking" may occur. Wicking is a phenomenon in which a stranded or braided conductor to be connected can draw molten solder away from the joint area by capillary action in the manner of a wick, and 90 cause the joint area to be depleted of 901der. This is often associated with undue stiffness in the portion of stranded or braided conductor adjacent to the joint due to the presence of the solder. Depletion of the solder in the joint area can cause the joint to have an unacceptably high resistance, or can cause mechanical failure of the joint, especially where the connected conductors have become stiff. The tendency of conductors to cawe wicking generally increases with temperature, and it appears that continued heating of the devic~ to cause the high temperature solder to melt can e~acerbate the problem.
According to the present invention, there is provided a composite solder article which comprise~:
' Tt~d Kingdom P.. ~ ;cal BSTIT~JTE S~EE-, T'CT Intemational App!lçs~ J
..... . . .. .. ..
. ~ . " . .. , , ~ , .
. . . . .
WO 90/092~5 PCr/GB90/00234 ~ - 2~5~3 (a) - quanc t~ ~f ~ _ase solden ~ni^s compr:ses a non-eute^- c alloy ~.` ,;o cr more me~ais; and (b~ a emperature control component comprising one or more metals. and having a melting point that is ~.igher than the solidus temperature of tne non-eutectic alloy, the :emperature ^ontrol ~omponent navi-.g _ucn a composicion, and ~he relative quantit.es ^f rhe temperature control element and the base s~ider ~eing such, that when the b~se solder and the :emperature control component have been fused osether the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
In use, when a solder joint is formed, the composite solder is heated, and, instead e melting, the oase solder becomes pasty as the temperature rises above the solidus temperature of the .on-eutectic composition, the pasty nature of the base solder preventing or retarding the tendency of ~he solder to be drawn or to "wick" along any of the conductors.
As heating of the solder is continued, 't has been observed that the temperature control com20nent can dissolve in the fused or pasty base solder at a temperature significantly below its melting point, thereby reducing the probability that the joint will be heated to such an extent that substantial wicking .. . .
.
WO 90/0925~ PCr/GB90/00234 i~3 - -occurs. -ven thougn ~.~ rempera~ure ^ontroi ~a~^r.en~
~ay never reacn i:s ~el~ g ?oin- ~erore i: ~ sa~_earC~
the aisappearance of ~ ~ay nevercneiess be use~ 5S 5-.
indication ~hat 'he -ase solder has ~eltea ~U_;J
because the 'iquidus emperature cf the non-eute^t c alloy ~alls as .~ore of :he :emperature ~oncroi component dissolves in i:.
Preferably the melting point of the ;empera~ure control component is preferably higher :.~an :he :iquidus ~emperature af ~e base soider, e.s. ^ :~s-5C higher and especiail~ at least '~C hisher :..an :he liquidus temperature, but preferably not more rhan ~,C
higher, and especially ~ot more than 2~^ higner ~han the liquidus point.
In many instances it may be desirable for the temperature control component to exhibit a substantially well defined melting point, in which case a substantially pure elemental metal may be chosen or a eutectic 2110y. Dreferably the emperature control component comprises a metal that is also present n the base solder. For example the base solder may have compositions that lie on Qpposite sides of the eutectic point in the phase ~iagram of the base solder components. One example of such a sy~tem is a composite solder having a base solder comprising a non eutectic tin lead alloy having le~s than the eutectic quantity (63S by weight) of tin, and a temperature control component having a relatively high tin content, e.g. subQtantially pure tin or a eutectic 96.5S tin 3.5S silver alloy. It may well be deQirable for the composition-Q and the relative proportions of the base ~ --.. ~ , ., ,:
,, , :. . -. ~ ~ , ':. ' ', - ::
wo ~/0925~ PCT/GB90tO02~
2 ~ 8 3 sold~ nd the ~emper2~ure c^ntr^_ somDOne.n~ -_ ce sucn ~hat ne overei: ^ompos ~e ~ider ~r~ cle nas compos :ion fall~n3 substan~ aily ,: :he ~utec~l~
point. In this ~ay .t can be ansured 'hat ail the solder ;qas melted at the lowest ?ossible temperature.
~ ormally the ~uantity of base solder ~ill e greater ~han that ~f the temperature control component.
usuall~J significantly greater, e.g. in a proportion o~
at lcast 2:1, preferably ~:1 and esDecially at ieast 5:1 ~_ll percentages. ratios ^nd ~he :ike ~xpressee herein being measured by weight), .n wrich case :he temperature control ring will usually be formed from a pure metal that is used in the non-eutectic alloy, wnile the ba-qe solder will have a composition that is relatively cloqe to the eutectic composition, e.g. not more than 30S, more preferably not more than 10S and especially not more than 10S removed from the eutectic point (e.g. in the caqe of a two component system). In the case of a tin/lead solder composition, which has a eutectic point at 63S tin, 37S iead (m.p. 1830C) he composite solder ?referably comprises ~ strip of lase solder ^omprising not more :han 62S ~in, more p-eferably not more than 61S tin, but preferably 3t least ~OS and especially at least 50S ~in, ~he remainder be$ng lead, and a thin strip of pure tin bonded to the base solder.
The baqe solder may be formed from a number of metals in addition to, or in~tead of, tin and lead, e.g. bismuth, indium or cadmium. Optionally quantities of other metals such as silver may be present n addition.
.
. , ' ~ ':, . ' ' .
woso/09255 PCT/GB9G/002~
~Q~5~3 The ~o ?or~1Ons o: tne ~mD~sl:e s~lder .ay ~e joinea ~~echen ~y 2nV cf _ ~.U~.De~ ,eans. -or example hey ~ay ~e ^onded :o~e~ner ~r ~xam?le ^;
means of an adhesive or by means c. :.~e solder f'ux, or they may be solderea :osether, either -y means of ~
third solder material or by means c~ the s~me solder as is used to form either of the :~o ?or~ions of the device. Alternatively the solder ?ortions may be bonded together by cold working. ~his may be achieved for example in ~he case of an -nnulan nsert ~v 5 stamping cperation i~ which one ~or-ion. e.g. . ~he form of ~ collar, ls bonded to the second portion in the form of an annular ~lange as ~he second portion is stamped out of a bl^nK sheet. ~nother ~ethod of cold working the two portions together that may be used to form the composite solder insert is a cold rolling method in which two or more strips of solder material, including at least one strip each of the high and low melting point solder are ~uxtaposed or overlapped, or one is placed upon the other, and then rolled to bond the strips together. ~he composite strip so formed can then be cut to iength and the ^~t engths wrapped around an appropriately shaped 3andre~ to form a wrapped solder insert or may be wrapped around the mandrel and then cut to length. Yet another method of forming the composite solder includes forming separate appropriately shaped inserts and then preQs fitting inserts formed from different solder material together.
Whichever form of composite solder s used, it is preferred that the individual, discrete, portions formed from a least one of the solder materials are formed only at the same time as the composite solder .
:, :
, wo ~/09255 PCT/GB90/002~
2 ~ 3 lnser~ s formeà. ~:~at ;s ~~ say, -he c~mpos e :nser~
is ~-eferaDly ^n~.ea ~v -n ^Deracion :..a: ioes .~o~
invoive the pnior -_rmation of d screte solden ~or~ions of bo~h solder -.3terials. Sucn opera~ions ~.~ve :he advantage that no~ .~ore than _ne ;ype ^f ndividual solder insert ~a employea at any one :.me, with considerable simpiification of :he handling of the solder. Examples of such oper~tions nclude ^old rolling Of solden strips followed by ^;qoppins and wrapping the str ?s, and s~amping operations ~ which one portion is s~ampea out of a DianK shee~ e: ;ne same time as it is bonaed to the other ?ortion.
The insert 13 preferably formed f-~oM a strip of solder that is formed into an appropriate shape for the solder device, for example by wrapping it around a mandrel. When forming this type of insert it is often necessary for the two strips of solder that make up the composite strip to be attached together by some means at least until the di~crete composite insert has been formed. Often, f,r example where one solder strip is positioned in a groove in the other solder s~rip the two strips will be retained together by ~heir shape when the strip has been wrapped round the mandrel to form the discrete device. The insert is preferably formed in such a way that no material is present in the in~ert other than solder or flux, or that, at most, only an in~ignificant quantity of such material is present. This form of solder insert may be formed in a number of ways: ~he two different solder strips may be a~embled together with no adhesive to form a composite solder strip, and ~hen the strips may be stuck together by means of a removable adhesive applied to the surface , ;
: . . .. .
:, ., ' ,~
, ;
... . . .
W090/09255 PCT/GB90/002~
2 ~ 3 _ only of the composi:~ s:ri?- '.fte^ :he s~ri~ n_s Jeen :~rapped -rouna ,he .andre~ o f^rm he aa.~?^si e inser~, 30 ~hat ~he adhesive ~ 3 no _onser ,~^ecsarf, the adhesive may be removed, e.g. av heat on ~.f~ared radiation or by application cf -n appropriate ~3ivenc, and the manufacturin5 process may ~e continuea .^. Che conventional manner. Alternacively the two ~:ri?s of solder may ~e held together by means of an ^dhesive coated paper layer that ^an be peeied away f-~ ~he co~posite ~rip ~ust ?rior ~o wrappin~ the c r _ -aout ;he mandrel.
. .
In another form of ~evice the two strips cf solder may ~e welded together for example by an elec~rical welding method in which a pair of electrodes is pressed against opposite sideg Or the composite solder strip and a current is passed through the composite strip that welds the strips together by joule heatins. In yet another form of device the two strips are 'oined together by a train of la-~er welds in which a laser is fired at ^ spot on the strip and forms a hole ~hrough Che composite strip and, at the same timel ~onas ~he two strips together. This form of joining Che s rips tosether has the advantage- that it is very rapid. and that a numb'er of small holes are formed in the insert through which solder can flow when the device is heated. A further form Or device can incoporace an insert that has been formed from a co-extruded strip Or solder.
Another method in which the composite inser~ can be formed without the prior ~ormation of _iscrete solder portions is one in which the insert .s formed , . . ... . . .
,. ... .. .. . . .
, ,, ,~ ' ~ ;
- , .
:. ,:.: . ;., WO 90/092~5 PCr/GB90/00234 9 - 2 Q ~ 3 ~rom ~pac~ea. ~referabl; in~eres colder ~owder Thus. .~r exam?ie. :he low cn ~. gn mel::.g ps s- solder powder .nay ae ~lacea ~n _ mould and sin~ered un~en pressure, and then ~he other colder ?owder may ~e added to the aame mould and itse!~ sintered under ^ressure and at a temperature of up to 150C to sinter both powders together.
The composite solder -,ay ~e employed i~. a hea;-shrinkable article as mentioned above, in which case it is Drererable, although .~ot 5 ssential, ror ~he ~ase solder ,nd :he temperature contol component to be bonded 'ogether. Thus, accordins to another ~spect, the isven~ion pro~ides a device for forming a solder connect.on between a plurality of elongate objects, which comprises a dimensionally heat-recoverable sleeve which contains:
(a) a quantity of a baQe solder which comprise~ a non-eu~ectic alloy of two or more metals; and (b) a temperature control component comprising one ~r more metals, and having a melting point that is higher than the solidus temperature of the non-eutectic alloy, - -the temperature control component having such 2 composition, and the relative quantities of the temperature control element and the base solder being such, ~hat when the base solder and the temperature control component have been fused .' , .,, ~ , " ,, , ,, ~ . .
' " ' ' ~:
, :', ' . ' , F ~ 9 3 / U
a 8 Mc:~ch ~'`?~
-lo- O 8 03 9 together the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
The hest-recoverable sleeve may be formed from any polymeric material that can be rendered dimensionally heat-recoverable by crosslinking and e~cpansion as described in the patent specifications described above. Preferred materials include ethylene homo- and copolymers such as low, medium or high density polyethylene, copoly ners of ethylene with C3 to C6 alpha olefins and ethylene/vinyl acetate copolymers. Preferred materials include fluorocarbon polymers, for esample polyvinylidine fluoride.
An esample of an article and device in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which: -, Figure 1 iB a schematic new of a composite solder article;
Figure 2 is an isometric ~iew of a solder ring formed by wrapping the article of figure 1; and Figure 3 is a side sectional elevation of heat-shrinkable connector article in accordance with the invention.
Referring to the accompanying drawings, figures 1 and 2 show schematically the steps in the manufacture of a solder device that employs an insert from a rUnited Kingdom~f ~ ~UBSTITUTE SHEET
I PCT International Applicatlon . ...
. : , :' ' WOgo/09255 PCT/GB90/002~
2~4~83 wra?ped composite s~rip 1. ~s shown, :~e s rip comprises a major C~ri? ~ c. ^on-eutec~:~ s^ider ^nd ~
smaller str ? ~ of ~ure ~.n wnich are hei~ ether by means of a smail quantl~y ~ of ~ water ;oluble cr cyanoacrylate adhesive. Alternatively ;nd ?referably the two strips 2 and 3 may be bonded tosetner by means of rosin flux 'hat is employed in the ~older. The solder strip is formed fnom a binary allov ^omprising 60S tin, 40S iead, which has a soli~us :emperature equal to the Sns3 ~b~7 eutectic tempera~ure ~f 1830C
and a liquidus ~emDerature Ol~ about 'Q80~. ~he sure tin strip has a melting point c~ ~31C.
After the composite strip nas been ~rmed, it is wrapped around a mandrel and cut (not necessarily in that order) in order to form an annular insert for a ~older connection device. Such a connection device is shown in figure 3. The device comprises a heat-Qhrinkable polyvinylidine fluoride sleeve 5 that has been partially recovered about the compos$te solder ring 1 and about two uncrosslinked sealing rings 7 and 8 which may be formed from a conventional hot-melt adhesive e.g. polyethylene, an ethylene J nyl acetate copolymer, a polyamide or a fluoropolymer such as polyvinylidine fluoride.
In UQe, a pair of obJects to be connected, e.g.
stranded electrical wires or a wire and a coaxial cable having an expoQed braid, may be inQerted .n the device and the device is simply heated to cause ~he sleeve 6 to recover about the ob~ects, the composite ~older strip to melt and .low about the objecrs and the sealing rings ~o fuse and provide ~ seal against .
, .
~. , ' , . . .
W090/0925~ PCT/GB90/002~
2~55~3 ~oisture in~ress. As the aevice is heated t.qe :r:~ c o~ ~ase _older ~ill ~:se n ~emDera~ure 3bo~te ,:5 soiidus :emperature ana will ~ecome ?asty, ~he _^sey nature restricting the degree to whicn the solden w.ii :-low aiong :o objects. As the emperature rises :.~e strip 2 rises above its l;quidus ;emperature and ~egins ~o dissolve the tin temperature control strip 3 so that a~ about 215 to 220C the tin strip 3 has dissol~ed and the sleeve has completely recovereà.
If desireà an alloy of ,02 in 502 ieaa .~.2y ^e ~Ised for the base solder strip 2 together ;;ith a slightly larger temperature control strip 3, i~ which ^ase the strip ~ will remain pasty until the i.quidus temperature of about 212C has been reached, ~hereby reducing further the propensity of the fused solder composition to flow along the objects.
,, : ,: .. .
- , : . . .
. . .
, COMPCSI~- SOLD~R ARTI~'~
-This invention relates ;o solder and n particular to so-called "soft solder", ~hat ~s tO say, solde-normaliy containin~ :.n -nd/or `eaà and bavin~ _ relat.~ely l~w meit n~ Doint, -.5. iess :han ~oor, as distinct from hard solder used for Drazing. -Solder has been used .or many ye2rs for the protection of strong, high quality electrical and mech-anical connections. Recently electrical connector devices have been made in which a quantity of solder is located within a dimensionally heat-recoverable article, usually in the form of a sleeve, optionally together with one or more f~sible plastics inserts for sealin~ he connection from ngress of water. The article may be placed over he objects to be connected and may then be heated to cause the solder to fuse and form ~ connection between the objects and to cause the article to recover about the objects and provide electrical in~ulation for ~he connection. These articleq are described for example in US patent specifications Nos. 3,243,211, 4,282,396 and 4,283,~96 and in ~ritish patent specification No. 1,470,049, ~he disclo~ures of which are incorporated herein by reference, and are sold by Raychem Corporation, Menlo Park, alifornia under the trade name "Solder Sleeve"
and others.
-,, -, . . . . .
. .
, . . . . . .
.. . .
I l,i A .~3 ~.1 0 / U ti ~ ~ , o 8 ~,larch 1~108 D3 91 In International Patent Application No. W088/09068 it has been proposed to employ a composite solder insert in such devices, the composite solder insert comprising a relatively low melting point solder and a relative high melting point solder, so that, during installation of the device, the device will be heated until the relatively high melting point solder has melted, thereby ensuring that the relatively low melting point solder has received sufficient heat to cause it to melt and flow.
Although such articles function well in most instances, it has been observed that in certain cases where the device is employed with highly solder receptive substrates such as with silver coated wires, so-called "wicking" may occur. Wicking is a phenomenon in which a stranded or braided conductor to be connected can draw molten solder away from the joint area by capillary action in the manner of a wick, and 90 cause the joint area to be depleted of 901der. This is often associated with undue stiffness in the portion of stranded or braided conductor adjacent to the joint due to the presence of the solder. Depletion of the solder in the joint area can cause the joint to have an unacceptably high resistance, or can cause mechanical failure of the joint, especially where the connected conductors have become stiff. The tendency of conductors to cawe wicking generally increases with temperature, and it appears that continued heating of the devic~ to cause the high temperature solder to melt can e~acerbate the problem.
According to the present invention, there is provided a composite solder article which comprise~:
' Tt~d Kingdom P.. ~ ;cal BSTIT~JTE S~EE-, T'CT Intemational App!lçs~ J
..... . . .. .. ..
. ~ . " . .. , , ~ , .
. . . . .
WO 90/092~5 PCr/GB90/00234 ~ - 2~5~3 (a) - quanc t~ ~f ~ _ase solden ~ni^s compr:ses a non-eute^- c alloy ~.` ,;o cr more me~ais; and (b~ a emperature control component comprising one or more metals. and having a melting point that is ~.igher than the solidus temperature of tne non-eutectic alloy, the :emperature ^ontrol ~omponent navi-.g _ucn a composicion, and ~he relative quantit.es ^f rhe temperature control element and the base s~ider ~eing such, that when the b~se solder and the :emperature control component have been fused osether the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
In use, when a solder joint is formed, the composite solder is heated, and, instead e melting, the oase solder becomes pasty as the temperature rises above the solidus temperature of the .on-eutectic composition, the pasty nature of the base solder preventing or retarding the tendency of ~he solder to be drawn or to "wick" along any of the conductors.
As heating of the solder is continued, 't has been observed that the temperature control com20nent can dissolve in the fused or pasty base solder at a temperature significantly below its melting point, thereby reducing the probability that the joint will be heated to such an extent that substantial wicking .. . .
.
WO 90/0925~ PCr/GB90/00234 i~3 - -occurs. -ven thougn ~.~ rempera~ure ^ontroi ~a~^r.en~
~ay never reacn i:s ~el~ g ?oin- ~erore i: ~ sa~_earC~
the aisappearance of ~ ~ay nevercneiess be use~ 5S 5-.
indication ~hat 'he -ase solder has ~eltea ~U_;J
because the 'iquidus emperature cf the non-eute^t c alloy ~alls as .~ore of :he :emperature ~oncroi component dissolves in i:.
Preferably the melting point of the ;empera~ure control component is preferably higher :.~an :he :iquidus ~emperature af ~e base soider, e.s. ^ :~s-5C higher and especiail~ at least '~C hisher :..an :he liquidus temperature, but preferably not more rhan ~,C
higher, and especially ~ot more than 2~^ higner ~han the liquidus point.
In many instances it may be desirable for the temperature control component to exhibit a substantially well defined melting point, in which case a substantially pure elemental metal may be chosen or a eutectic 2110y. Dreferably the emperature control component comprises a metal that is also present n the base solder. For example the base solder may have compositions that lie on Qpposite sides of the eutectic point in the phase ~iagram of the base solder components. One example of such a sy~tem is a composite solder having a base solder comprising a non eutectic tin lead alloy having le~s than the eutectic quantity (63S by weight) of tin, and a temperature control component having a relatively high tin content, e.g. subQtantially pure tin or a eutectic 96.5S tin 3.5S silver alloy. It may well be deQirable for the composition-Q and the relative proportions of the base ~ --.. ~ , ., ,:
,, , :. . -. ~ ~ , ':. ' ', - ::
wo ~/0925~ PCT/GB90tO02~
2 ~ 8 3 sold~ nd the ~emper2~ure c^ntr^_ somDOne.n~ -_ ce sucn ~hat ne overei: ^ompos ~e ~ider ~r~ cle nas compos :ion fall~n3 substan~ aily ,: :he ~utec~l~
point. In this ~ay .t can be ansured 'hat ail the solder ;qas melted at the lowest ?ossible temperature.
~ ormally the ~uantity of base solder ~ill e greater ~han that ~f the temperature control component.
usuall~J significantly greater, e.g. in a proportion o~
at lcast 2:1, preferably ~:1 and esDecially at ieast 5:1 ~_ll percentages. ratios ^nd ~he :ike ~xpressee herein being measured by weight), .n wrich case :he temperature control ring will usually be formed from a pure metal that is used in the non-eutectic alloy, wnile the ba-qe solder will have a composition that is relatively cloqe to the eutectic composition, e.g. not more than 30S, more preferably not more than 10S and especially not more than 10S removed from the eutectic point (e.g. in the caqe of a two component system). In the case of a tin/lead solder composition, which has a eutectic point at 63S tin, 37S iead (m.p. 1830C) he composite solder ?referably comprises ~ strip of lase solder ^omprising not more :han 62S ~in, more p-eferably not more than 61S tin, but preferably 3t least ~OS and especially at least 50S ~in, ~he remainder be$ng lead, and a thin strip of pure tin bonded to the base solder.
The baqe solder may be formed from a number of metals in addition to, or in~tead of, tin and lead, e.g. bismuth, indium or cadmium. Optionally quantities of other metals such as silver may be present n addition.
.
. , ' ~ ':, . ' ' .
woso/09255 PCT/GB9G/002~
~Q~5~3 The ~o ?or~1Ons o: tne ~mD~sl:e s~lder .ay ~e joinea ~~echen ~y 2nV cf _ ~.U~.De~ ,eans. -or example hey ~ay ~e ^onded :o~e~ner ~r ~xam?le ^;
means of an adhesive or by means c. :.~e solder f'ux, or they may be solderea :osether, either -y means of ~
third solder material or by means c~ the s~me solder as is used to form either of the :~o ?or~ions of the device. Alternatively the solder ?ortions may be bonded together by cold working. ~his may be achieved for example in ~he case of an -nnulan nsert ~v 5 stamping cperation i~ which one ~or-ion. e.g. . ~he form of ~ collar, ls bonded to the second portion in the form of an annular ~lange as ~he second portion is stamped out of a bl^nK sheet. ~nother ~ethod of cold working the two portions together that may be used to form the composite solder insert is a cold rolling method in which two or more strips of solder material, including at least one strip each of the high and low melting point solder are ~uxtaposed or overlapped, or one is placed upon the other, and then rolled to bond the strips together. ~he composite strip so formed can then be cut to iength and the ^~t engths wrapped around an appropriately shaped 3andre~ to form a wrapped solder insert or may be wrapped around the mandrel and then cut to length. Yet another method of forming the composite solder includes forming separate appropriately shaped inserts and then preQs fitting inserts formed from different solder material together.
Whichever form of composite solder s used, it is preferred that the individual, discrete, portions formed from a least one of the solder materials are formed only at the same time as the composite solder .
:, :
, wo ~/09255 PCT/GB90/002~
2 ~ 3 lnser~ s formeà. ~:~at ;s ~~ say, -he c~mpos e :nser~
is ~-eferaDly ^n~.ea ~v -n ^Deracion :..a: ioes .~o~
invoive the pnior -_rmation of d screte solden ~or~ions of bo~h solder -.3terials. Sucn opera~ions ~.~ve :he advantage that no~ .~ore than _ne ;ype ^f ndividual solder insert ~a employea at any one :.me, with considerable simpiification of :he handling of the solder. Examples of such oper~tions nclude ^old rolling Of solden strips followed by ^;qoppins and wrapping the str ?s, and s~amping operations ~ which one portion is s~ampea out of a DianK shee~ e: ;ne same time as it is bonaed to the other ?ortion.
The insert 13 preferably formed f-~oM a strip of solder that is formed into an appropriate shape for the solder device, for example by wrapping it around a mandrel. When forming this type of insert it is often necessary for the two strips of solder that make up the composite strip to be attached together by some means at least until the di~crete composite insert has been formed. Often, f,r example where one solder strip is positioned in a groove in the other solder s~rip the two strips will be retained together by ~heir shape when the strip has been wrapped round the mandrel to form the discrete device. The insert is preferably formed in such a way that no material is present in the in~ert other than solder or flux, or that, at most, only an in~ignificant quantity of such material is present. This form of solder insert may be formed in a number of ways: ~he two different solder strips may be a~embled together with no adhesive to form a composite solder strip, and ~hen the strips may be stuck together by means of a removable adhesive applied to the surface , ;
: . . .. .
:, ., ' ,~
, ;
... . . .
W090/09255 PCT/GB90/002~
2 ~ 3 _ only of the composi:~ s:ri?- '.fte^ :he s~ri~ n_s Jeen :~rapped -rouna ,he .andre~ o f^rm he aa.~?^si e inser~, 30 ~hat ~he adhesive ~ 3 no _onser ,~^ecsarf, the adhesive may be removed, e.g. av heat on ~.f~ared radiation or by application cf -n appropriate ~3ivenc, and the manufacturin5 process may ~e continuea .^. Che conventional manner. Alternacively the two ~:ri?s of solder may ~e held together by means of an ^dhesive coated paper layer that ^an be peeied away f-~ ~he co~posite ~rip ~ust ?rior ~o wrappin~ the c r _ -aout ;he mandrel.
. .
In another form of ~evice the two strips cf solder may ~e welded together for example by an elec~rical welding method in which a pair of electrodes is pressed against opposite sideg Or the composite solder strip and a current is passed through the composite strip that welds the strips together by joule heatins. In yet another form of device the two strips are 'oined together by a train of la-~er welds in which a laser is fired at ^ spot on the strip and forms a hole ~hrough Che composite strip and, at the same timel ~onas ~he two strips together. This form of joining Che s rips tosether has the advantage- that it is very rapid. and that a numb'er of small holes are formed in the insert through which solder can flow when the device is heated. A further form Or device can incoporace an insert that has been formed from a co-extruded strip Or solder.
Another method in which the composite inser~ can be formed without the prior ~ormation of _iscrete solder portions is one in which the insert .s formed , . . ... . . .
,. ... .. .. . . .
, ,, ,~ ' ~ ;
- , .
:. ,:.: . ;., WO 90/092~5 PCr/GB90/00234 9 - 2 Q ~ 3 ~rom ~pac~ea. ~referabl; in~eres colder ~owder Thus. .~r exam?ie. :he low cn ~. gn mel::.g ps s- solder powder .nay ae ~lacea ~n _ mould and sin~ered un~en pressure, and then ~he other colder ?owder may ~e added to the aame mould and itse!~ sintered under ^ressure and at a temperature of up to 150C to sinter both powders together.
The composite solder -,ay ~e employed i~. a hea;-shrinkable article as mentioned above, in which case it is Drererable, although .~ot 5 ssential, ror ~he ~ase solder ,nd :he temperature contol component to be bonded 'ogether. Thus, accordins to another ~spect, the isven~ion pro~ides a device for forming a solder connect.on between a plurality of elongate objects, which comprises a dimensionally heat-recoverable sleeve which contains:
(a) a quantity of a baQe solder which comprise~ a non-eu~ectic alloy of two or more metals; and (b) a temperature control component comprising one ~r more metals, and having a melting point that is higher than the solidus temperature of the non-eutectic alloy, - -the temperature control component having such 2 composition, and the relative quantities of the temperature control element and the base solder being such, ~hat when the base solder and the temperature control component have been fused .' , .,, ~ , " ,, , ,, ~ . .
' " ' ' ~:
, :', ' . ' , F ~ 9 3 / U
a 8 Mc:~ch ~'`?~
-lo- O 8 03 9 together the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
The hest-recoverable sleeve may be formed from any polymeric material that can be rendered dimensionally heat-recoverable by crosslinking and e~cpansion as described in the patent specifications described above. Preferred materials include ethylene homo- and copolymers such as low, medium or high density polyethylene, copoly ners of ethylene with C3 to C6 alpha olefins and ethylene/vinyl acetate copolymers. Preferred materials include fluorocarbon polymers, for esample polyvinylidine fluoride.
An esample of an article and device in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which: -, Figure 1 iB a schematic new of a composite solder article;
Figure 2 is an isometric ~iew of a solder ring formed by wrapping the article of figure 1; and Figure 3 is a side sectional elevation of heat-shrinkable connector article in accordance with the invention.
Referring to the accompanying drawings, figures 1 and 2 show schematically the steps in the manufacture of a solder device that employs an insert from a rUnited Kingdom~f ~ ~UBSTITUTE SHEET
I PCT International Applicatlon . ...
. : , :' ' WOgo/09255 PCT/GB90/002~
2~4~83 wra?ped composite s~rip 1. ~s shown, :~e s rip comprises a major C~ri? ~ c. ^on-eutec~:~ s^ider ^nd ~
smaller str ? ~ of ~ure ~.n wnich are hei~ ether by means of a smail quantl~y ~ of ~ water ;oluble cr cyanoacrylate adhesive. Alternatively ;nd ?referably the two strips 2 and 3 may be bonded tosetner by means of rosin flux 'hat is employed in the ~older. The solder strip is formed fnom a binary allov ^omprising 60S tin, 40S iead, which has a soli~us :emperature equal to the Sns3 ~b~7 eutectic tempera~ure ~f 1830C
and a liquidus ~emDerature Ol~ about 'Q80~. ~he sure tin strip has a melting point c~ ~31C.
After the composite strip nas been ~rmed, it is wrapped around a mandrel and cut (not necessarily in that order) in order to form an annular insert for a ~older connection device. Such a connection device is shown in figure 3. The device comprises a heat-Qhrinkable polyvinylidine fluoride sleeve 5 that has been partially recovered about the compos$te solder ring 1 and about two uncrosslinked sealing rings 7 and 8 which may be formed from a conventional hot-melt adhesive e.g. polyethylene, an ethylene J nyl acetate copolymer, a polyamide or a fluoropolymer such as polyvinylidine fluoride.
In UQe, a pair of obJects to be connected, e.g.
stranded electrical wires or a wire and a coaxial cable having an expoQed braid, may be inQerted .n the device and the device is simply heated to cause ~he sleeve 6 to recover about the ob~ects, the composite ~older strip to melt and .low about the objecrs and the sealing rings ~o fuse and provide ~ seal against .
, .
~. , ' , . . .
W090/0925~ PCT/GB90/002~
2~55~3 ~oisture in~ress. As the aevice is heated t.qe :r:~ c o~ ~ase _older ~ill ~:se n ~emDera~ure 3bo~te ,:5 soiidus :emperature ana will ~ecome ?asty, ~he _^sey nature restricting the degree to whicn the solden w.ii :-low aiong :o objects. As the emperature rises :.~e strip 2 rises above its l;quidus ;emperature and ~egins ~o dissolve the tin temperature control strip 3 so that a~ about 215 to 220C the tin strip 3 has dissol~ed and the sleeve has completely recovereà.
If desireà an alloy of ,02 in 502 ieaa .~.2y ^e ~Ised for the base solder strip 2 together ;;ith a slightly larger temperature control strip 3, i~ which ^ase the strip ~ will remain pasty until the i.quidus temperature of about 212C has been reached, ~hereby reducing further the propensity of the fused solder composition to flow along the objects.
,, : ,: .. .
- , : . . .
. . .
Claims (15)
1. A composite solder article which comprises:
(a) a quantity of a base solder which comprises a non-eutectic alloy of two or more metals; and (b) a temperature control component comprising one more metals, and having a melting point that is higher than the solidus temperature of the non-eutectic alloy, the temperature control component having such composition, and the relative quantities of the temperature control element and the base solder being such, that when the base solder and the temperature control component have been fused together the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
(a) a quantity of a base solder which comprises a non-eutectic alloy of two or more metals; and (b) a temperature control component comprising one more metals, and having a melting point that is higher than the solidus temperature of the non-eutectic alloy, the temperature control component having such composition, and the relative quantities of the temperature control element and the base solder being such, that when the base solder and the temperature control component have been fused together the resulting solder alloy has a smaller difference between its liquidus and solidus temperatures than has the base solder.
2. An article as claimed in claim 1, wherein the melting point of the temperature control component is higher than the liquidus temperature of the base solder.
3. An article as claimed in claim 1 or claim 2, wherein the melting point of the temperature control component is at least 10°C nigher than the liquidus temperature of the base solder.
4. An article as claimed in any one of claims 1 to 3, wherein the quantity of base solder is greater than that of the temperature control component.
5. An article as claimed in 4, wherein the proportion of base solder to temperature control component is at least 5:1.
6. An article as claimed in any one of claims 1 to 5, wherein the temperature control component comprises a substantially pure metal or a eutectic alloy.
7. An article as claimed in any one of claims 1 to 6, wherein the temperature control component comprises a metal that is present in the base solder.
8. An article as claimed in claim 7, wherein the base solder and the temperature control component have compositions that lie on opposite sides of the eutectic point in the phase diagram of the base solder components.
9. An article as claimed in any one of claims 1 to 8, wherein the base solder comprises any one or more of the following: tin, lead, indium or bismuth.
10. An article as claimed in claim 9, wherein the base solder comprises an alloy of tin and lead.
11. An article as claimed in claim 10, wherein the base solder has a composition in the range of from 62%
tin 38% lead to 40% tin 60% lead.
tin 38% lead to 40% tin 60% lead.
12. An article as claimed in claim 11, wherein the base solder has a composition in the range of from 61%
tin 39% lead to 50% tin 50% lead.
tin 39% lead to 50% tin 50% lead.
13. An article as claimed in any one claims 1 to 12, wherein the temperature control component comprises substantially pure tin or a 96.5% tin 3.5% silver eutectic alloy.
14. An article as claimed in any one of claims to 13, which is in the form of a strip.
15. A device for forming an electrical or mechanical connection, which comprises a heat-shrinkable polymeric sleeve and a composite solder article as claimed in any one of claims 1 to 14 retained within the sleeve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898903311A GB8903311D0 (en) | 1989-02-14 | 1989-02-14 | Composite solder article |
| GB8903311.2 | 1989-02-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2045683A1 true CA2045683A1 (en) | 1990-08-15 |
Family
ID=10651661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002045683A Abandoned CA2045683A1 (en) | 1989-02-14 | 1990-02-13 | Composite solder article |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0458871A1 (en) |
| AU (1) | AU5156790A (en) |
| CA (1) | CA2045683A1 (en) |
| GB (1) | GB8903311D0 (en) |
| IL (1) | IL93375A (en) |
| WO (1) | WO1990009255A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9203289D0 (en) * | 1992-02-17 | 1992-04-01 | Raychem Sa Nv | Coaxial cable termination arrangement |
| US5331113A (en) * | 1992-10-30 | 1994-07-19 | Raychem Corporation | Electrical connector |
| DE102005040819A1 (en) * | 2005-08-27 | 2007-03-08 | Few Fahrzeugelektrikwerk Gmbh & Co. Kg | Lot and method for its attachment |
| US8410600B2 (en) | 2009-10-02 | 2013-04-02 | Arkansas Power Electronics International, Inc. | Semiconductor device with protecting film and method of fabricating the semiconductor device with protecting film |
| US8592986B2 (en) | 2010-11-09 | 2013-11-26 | Rohm Co., Ltd. | High melting point soldering layer alloyed by transient liquid phase and fabrication method for the same, and semiconductor device |
| US9673163B2 (en) | 2011-10-18 | 2017-06-06 | Rohm Co., Ltd. | Semiconductor device with flip chip structure and fabrication method of the semiconductor device |
| US9761506B2 (en) | 2012-02-23 | 2017-09-12 | Rohm Co., Ltd. | Semiconductor device and fabrication method for the same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2823122C2 (en) * | 1978-05-26 | 1983-11-24 | Nisshin Steel Co., Ltd., Tokyo | Process for soft soldering nested pipes made of stainless steel |
| GB2036794A (en) * | 1978-11-28 | 1980-07-02 | Semi Alloys Inc | Solder Preform |
| US4767471A (en) * | 1986-10-03 | 1988-08-30 | Texas Instruments Incorporated | Delayed reflow alloy mix solder paste |
| GB8710489D0 (en) * | 1987-05-02 | 1987-06-03 | Raychem Pontoise Sa | Solder connector device |
| GB8817192D0 (en) * | 1988-07-19 | 1988-08-24 | Raychem Pontoise Sa | Solder & connection device incorporating solder |
-
1989
- 1989-02-14 GB GB898903311A patent/GB8903311D0/en active Pending
-
1990
- 1990-02-13 IL IL9337590A patent/IL93375A/en not_active IP Right Cessation
- 1990-02-13 AU AU51567/90A patent/AU5156790A/en not_active Abandoned
- 1990-02-13 WO PCT/GB1990/000234 patent/WO1990009255A1/en not_active Application Discontinuation
- 1990-02-13 CA CA002045683A patent/CA2045683A1/en not_active Abandoned
- 1990-02-13 EP EP90903622A patent/EP0458871A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0458871A1 (en) | 1991-12-04 |
| IL93375A0 (en) | 1990-11-29 |
| IL93375A (en) | 1994-01-25 |
| WO1990009255A1 (en) | 1990-08-23 |
| AU5156790A (en) | 1990-09-05 |
| GB8903311D0 (en) | 1989-04-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |