CA1146112A - Method of forming a platinum layer on tantalum - Google Patents
Method of forming a platinum layer on tantalumInfo
- Publication number
- CA1146112A CA1146112A CA000331382A CA331382A CA1146112A CA 1146112 A CA1146112 A CA 1146112A CA 000331382 A CA000331382 A CA 000331382A CA 331382 A CA331382 A CA 331382A CA 1146112 A CA1146112 A CA 1146112A
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- Canada
- Prior art keywords
- tantalum
- electrode
- platinum
- platinizing
- workpiece
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Electroplating Methods And Accessories (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
Abstract
Abstract of the Disclosure A method of platinizing and heat treating tantalum metal is described. The platinizing of tantalum is accomplished by placing a piece of conductive corrosion resistant metal and a tantalum workpiece as electrodes in a platinizing solution. The electrodes are connected to a source of DC power supply and when the current is passed, platinum black is deposited on the tantalum work-piece. The platinized tantalum workpiece is then placed in a furnace maintained at a temperature of about 1050 to 1150°C for a time sufficient to diffuse the coated platinum into the surface of the tantalum core.
Description
1~ L2 ~ R 0~ TA~ATLU1 Bac~ round of the Inventlon This inve~tion relates.to a method of platini~ d ~eat tr~ati~g tantalu~ and ~ore particularly ta~talum S plugs to be us~-d as electrodes in th~ ~etection o faults : in reacti~ vessel protective linings.
It is a co~mon practice to use prot~ctive layers of glass enamel as an an~i~corrosive lining o~ ~e lnside of reac~io~ veesels which ontai~ corro~i~e liqulds~
: lO I~ suc~ vessels~ a ~ault in the protectl~e llning can : rea~}t in scr~ous corrosio~ o the vesse~ and i such a ~ault re~ai~ u~detected o~ some time~ the vessPl . may bec~e u~usable and irreparable~ ome cases~
: : the contents of the vessel may eve~ $eco~e co~tami~ated.
15 Thu8, it cs~n be~see~ that ~essels o~ this type must be : conti~uously monitored agal~st~ damage to the protec~ive lini~g.
: U.S. Paeene 39858,114 di~closes a ~h~d for de~ect ng~aults i~ reaction ves~el li~ings~ The method de 20 ~scribed~in this patent involve$ dispos~ng a pIati~u~ ;: :-electrode ~ a conductive mediu~ in the Yessel and ~easur-ing any current flowing from the electrode to the iron or steel wall of ~he reaction vesselO ht locations where damage has occurred to the lining, the current flow :~ 2; increases acco~rdingly. Th~ intensity of the current delivered by the so formed Pt-~e cell indicates the degree : of damage to the protective layer. The platinu~ metal .~ . used as an~electrode in U.S. Patent 3~85g,114 is very expensive~ It would thereore ~e worth~hile, lf possible, ;~
.
~o pla~e a tan~alum core with pla~iuum aud use lt as an electrode. Such a~ electrode would have a platinum ~urface and tantal~m core aud ~ould be legs expe~siYe tha~
conve~tionally platinum plateA e:Lectrode ~ Ta~talu~ has 5 been chosen as a core materlal because It 19 cor~sio~
resistant and should the plati~um laye~ of the elec~rode break dow~, the ta~talu~ will no~ ad~e~sely affect the conte~ts of the vesselO It has been found I~ practIce~
however, that con~entionally plated pIatnlum layers on ta~talu~ wear out rather quickly~ partj.cularly whe~ the conte~s of the ~essel con~ain an ab~asiYe materi~l ~uch as slurr~.
Obiec~s of the I~ventio~
~- Accordi~glyD it ls a~ ob~ect of this inYe~ti~ ~Q
prov~de a~ abrasion resistant pIatinum layer on th~ oute~
surface of a tantalum ~or~piece~
It is another ob~ect of this ~n~entlon to p~ovIde method of platiniæi~ and heat treat~D~ a t~.ntalu~ ~70xk~
: piece.
It i-4; yet another ob~ect o this inventIon to provide : au l~prcved ~lectrode ~r a reactio~ vesael fault f~der ; . o hi~h precis~o~ ~
: It is a ~urther ob~ect of the ~nYent~On tO p~nvide a method of obtai~in~ a thi~ stable layer o plati~Lm on . 25 : a ~antal~u workpiece. : .
It is yet another object of the ~nvent~on to provlde .
~: an ine~pe~sive platinum electrode~ -5u~ary of the Invention ~
These obj~cts and:other are accomplished i~ accordance with the present invention by providing a no~el method nf platinizing and heat treating a tantalum wo~kpiece~ The surface of the workpiece is first cleaned and then connected to the negatiYe lead of a æource of DC supply.
The positive lead of the DC suppl~ is then connected to a piece of corrosion~resistant conductive metal, such as lr ~
,4 . , ' . ' ' :
' platinu~, and both metals i~mersed i~ a platinizing solutioTl. A current is ~hen p~ssed through ~he ~-olutlon and platinum blac~ is deposi~ed on the ta~talum workplece.
The tantalum workp~ece ls then removed from the platin-i2ing solution and heated to a tempera~ure of about1050-1150C in a va~uum ~urnace~ os furnace contai~in~
an inert atmospbere, for a time suffic~e~ TO diffUe the plati~um into the su~face of ~he ~antaluTn. Thi~ -res~l~s in the for~atio~ of a ~an~alu~ workpiece whlch contains a ~table outer layer of platinum dlffu~ed iTl ~he surface of the t~ntalum, Thi~ proce~s ~nay be utilized to manufacture platinum coated parts ~uch ~ elec~rodes, -electrical probes, and repair plugs for glass liT~ed vessels.
It sho~ld be understood that ~aTltalum and tant~elum base alloys ~h~ch may be plati~ized and heat ~reated are included within the scope of this inVen~iOT~.. For e~ample~ tantalum alloyed ~lth tuTlgs~en coTnpr~ses a ~uitable alloy which may be used in place of tantalum i~ the.process o the present i~v~ntion.
: ~tailed IL~ tI~ f the Invention Within ~his disclosure. the t~rms platinum plated :~
a~d platinized ~re speci~icaily distingulshed ~ro~ e~ch other. Plati~um plating is carried out by co~ventional methods. A ~ell cleaned tantalu~ workpiece i5 ~astened in a chuck which i~ electrically charged~ A spo~ge dipped ¦.
in a platinum solution is held against the rotating tantalum core~ The process is continued until the desired thic~ness of platinum is formed o~ the surface of the ; 30 taDtalun.
In the platinizing and heat treatment process accord-ing to the present invention, a platinum black powder : coating is deposited on the tantalum workpiece by electro- j lysis~ The coated woxkpiece is then placed in 2 fuxnace : ¦
35 which is heated to about 1050-1150C., This heat treat-ment results in the diffusion of the platinum into the ~, , , : . , .
... .,.. : .. ' : ~ : , ` ~ , : :~
surface of the tantalum~ This dlffusion ~f the platinum i~to the surfa~e of the tantalu~ results in a ta~talum part containing a pla~inum surace which ls electrlcally - and mechanically superior to pla~ed pla~num part~ ~
The process of the presen~ i~ven~i~n results i~ a s~able platinum layer on the tan~alum sur~ace a~d makes the electrode abrasion resistant. Fur~her~ the platinum lsyer made according to the presant invention ~ ~hlnner . tha~ con~en~ionally plated pla~inum l.ayers~
In a preferred embodime~t of the pr~sent ~-nven~ion a ta~talum workpiece~ sultab~e ~or ul~lmate use as ~
electrode in ~he detectio~ of aul~5 in ~ reacti~ vessel, iB sandblasted to ~e~der the surface clean a~d ree of dlrt a~d grease. The tantalum c~re is i~ the orm o : ~5 a one piece 5/8 inch fla~ head sc~e~ and compri~e3 ~0%
by ~e~ght tantalum a~d 10% b~ weight tungsten~ The core is ~en brushed off and clea~ed with a 202 HCl ~o:Lution and washed~ The core may be st4xed i~ distilled water ; if plati~izi~g is ~o be don~ at ~ later ~tag~
Th~ followi~g ~aterial9 an~ appar~tus wera u~ed in the platinizing process:
. 1. Bea~er (200 ~1~ .
. 2. Plati~izi~g soluti~n ~lS0 ~1 - . 30 Slx Yolt DC powe~ source . 25 ~ 4.~ Small strlp o~ pla~num metal
It is a co~mon practice to use prot~ctive layers of glass enamel as an an~i~corrosive lining o~ ~e lnside of reac~io~ veesels which ontai~ corro~i~e liqulds~
: lO I~ suc~ vessels~ a ~ault in the protectl~e llning can : rea~}t in scr~ous corrosio~ o the vesse~ and i such a ~ault re~ai~ u~detected o~ some time~ the vessPl . may bec~e u~usable and irreparable~ ome cases~
: : the contents of the vessel may eve~ $eco~e co~tami~ated.
15 Thu8, it cs~n be~see~ that ~essels o~ this type must be : conti~uously monitored agal~st~ damage to the protec~ive lini~g.
: U.S. Paeene 39858,114 di~closes a ~h~d for de~ect ng~aults i~ reaction ves~el li~ings~ The method de 20 ~scribed~in this patent involve$ dispos~ng a pIati~u~ ;: :-electrode ~ a conductive mediu~ in the Yessel and ~easur-ing any current flowing from the electrode to the iron or steel wall of ~he reaction vesselO ht locations where damage has occurred to the lining, the current flow :~ 2; increases acco~rdingly. Th~ intensity of the current delivered by the so formed Pt-~e cell indicates the degree : of damage to the protective layer. The platinu~ metal .~ . used as an~electrode in U.S. Patent 3~85g,114 is very expensive~ It would thereore ~e worth~hile, lf possible, ;~
.
~o pla~e a tan~alum core with pla~iuum aud use lt as an electrode. Such a~ electrode would have a platinum ~urface and tantal~m core aud ~ould be legs expe~siYe tha~
conve~tionally platinum plateA e:Lectrode ~ Ta~talu~ has 5 been chosen as a core materlal because It 19 cor~sio~
resistant and should the plati~um laye~ of the elec~rode break dow~, the ta~talu~ will no~ ad~e~sely affect the conte~ts of the vesselO It has been found I~ practIce~
however, that con~entionally plated pIatnlum layers on ta~talu~ wear out rather quickly~ partj.cularly whe~ the conte~s of the ~essel con~ain an ab~asiYe materi~l ~uch as slurr~.
Obiec~s of the I~ventio~
~- Accordi~glyD it ls a~ ob~ect of this inYe~ti~ ~Q
prov~de a~ abrasion resistant pIatinum layer on th~ oute~
surface of a tantalum ~or~piece~
It is another ob~ect of this ~n~entlon to p~ovIde method of platiniæi~ and heat treat~D~ a t~.ntalu~ ~70xk~
: piece.
It i-4; yet another ob~ect o this inventIon to provide : au l~prcved ~lectrode ~r a reactio~ vesael fault f~der ; . o hi~h precis~o~ ~
: It is a ~urther ob~ect of the ~nYent~On tO p~nvide a method of obtai~in~ a thi~ stable layer o plati~Lm on . 25 : a ~antal~u workpiece. : .
It is yet another object of the ~nvent~on to provlde .
~: an ine~pe~sive platinum electrode~ -5u~ary of the Invention ~
These obj~cts and:other are accomplished i~ accordance with the present invention by providing a no~el method nf platinizing and heat treating a tantalum wo~kpiece~ The surface of the workpiece is first cleaned and then connected to the negatiYe lead of a æource of DC supply.
The positive lead of the DC suppl~ is then connected to a piece of corrosion~resistant conductive metal, such as lr ~
,4 . , ' . ' ' :
' platinu~, and both metals i~mersed i~ a platinizing solutioTl. A current is ~hen p~ssed through ~he ~-olutlon and platinum blac~ is deposi~ed on the ta~talum workplece.
The tantalum workp~ece ls then removed from the platin-i2ing solution and heated to a tempera~ure of about1050-1150C in a va~uum ~urnace~ os furnace contai~in~
an inert atmospbere, for a time suffic~e~ TO diffUe the plati~um into the su~face of ~he ~antaluTn. Thi~ -res~l~s in the for~atio~ of a ~an~alu~ workpiece whlch contains a ~table outer layer of platinum dlffu~ed iTl ~he surface of the t~ntalum, Thi~ proce~s ~nay be utilized to manufacture platinum coated parts ~uch ~ elec~rodes, -electrical probes, and repair plugs for glass liT~ed vessels.
It sho~ld be understood that ~aTltalum and tant~elum base alloys ~h~ch may be plati~ized and heat ~reated are included within the scope of this inVen~iOT~.. For e~ample~ tantalum alloyed ~lth tuTlgs~en coTnpr~ses a ~uitable alloy which may be used in place of tantalum i~ the.process o the present i~v~ntion.
: ~tailed IL~ tI~ f the Invention Within ~his disclosure. the t~rms platinum plated :~
a~d platinized ~re speci~icaily distingulshed ~ro~ e~ch other. Plati~um plating is carried out by co~ventional methods. A ~ell cleaned tantalu~ workpiece i5 ~astened in a chuck which i~ electrically charged~ A spo~ge dipped ¦.
in a platinum solution is held against the rotating tantalum core~ The process is continued until the desired thic~ness of platinum is formed o~ the surface of the ; 30 taDtalun.
In the platinizing and heat treatment process accord-ing to the present invention, a platinum black powder : coating is deposited on the tantalum workpiece by electro- j lysis~ The coated woxkpiece is then placed in 2 fuxnace : ¦
35 which is heated to about 1050-1150C., This heat treat-ment results in the diffusion of the platinum into the ~, , , : . , .
... .,.. : .. ' : ~ : , ` ~ , : :~
surface of the tantalum~ This dlffusion ~f the platinum i~to the surfa~e of the tantalu~ results in a ta~talum part containing a pla~inum surace which ls electrlcally - and mechanically superior to pla~ed pla~num part~ ~
The process of the presen~ i~ven~i~n results i~ a s~able platinum layer on the tan~alum sur~ace a~d makes the electrode abrasion resistant. Fur~her~ the platinum lsyer made according to the presant invention ~ ~hlnner . tha~ con~en~ionally plated pla~inum l.ayers~
In a preferred embodime~t of the pr~sent ~-nven~ion a ta~talum workpiece~ sultab~e ~or ul~lmate use as ~
electrode in ~he detectio~ of aul~5 in ~ reacti~ vessel, iB sandblasted to ~e~der the surface clean a~d ree of dlrt a~d grease. The tantalum c~re is i~ the orm o : ~5 a one piece 5/8 inch fla~ head sc~e~ and compri~e3 ~0%
by ~e~ght tantalum a~d 10% b~ weight tungsten~ The core is ~en brushed off and clea~ed with a 202 HCl ~o:Lution and washed~ The core may be st4xed i~ distilled water ; if plati~izi~g is ~o be don~ at ~ later ~tag~
Th~ followi~g ~aterial9 an~ appar~tus wera u~ed in the platinizing process:
. 1. Bea~er (200 ~1~ .
. 2. Plati~izi~g soluti~n ~lS0 ~1 - . 30 Slx Yolt DC powe~ source . 25 ~ 4.~ Small strlp o~ pla~num metal
2 x 1 1/4 x 1/32 i~che~) The platinizing solutio~ is prepared ln t~e beaker~
~: ~ The solution ccntain5 3 g~s of chloroplatlnic acid, 0.02 :~
~ ~ gms of lead aceta~e per 100 ml of distilled water. The ; 30 tantalum core described above is connected to the negative lead of the 6Y DC power supply and the platinum strip is connected to the positive lead o the 6V DC power supply. Both the platinum strip and the tantalum core are suspended in the solutio~ in the beaker~ Only the .
area of the tantalum that is to be platinized is immersed ~: :
..~ , .
~ .
.~n the solu~ion~ The vol~age i9 th~n applied for ~ix mi~utes during which time the platinu~ black i5 deposited on thc tantalum core~ The tantalu~ electrodc ls ~hen care~ully removed ~rom t~e solution and ~lnsed with dis-~illed water. The platinum black deposi~.ed is dull blackand no~-adherent at this s~ag~a. The electrode ~s then placed in a rack and placed in a ~urrlace main~ai~ed at a vacuùm of about lO-6 mm of ~ercury a~d a temp~rature of about 1150C or l/2.hour~ This heat treat~ent re~ults i~ the platinum bei~ diffused into the surface of the tantalu~ ~hich exhibits a dull gray appearance Option-ally, the eantalu~ corè may b platinized and heat 'c~eated ~or a seco~d time in order to.form a more stable a~d adherent platinum lay~
It has also bee~ found that the quallty of the plat-inizing a~d heat t~ea~ed electrode is better when ~i~er sand is used ~or blastingt rather than coarser. The surace roughness of the ta~talum core after ~,andblasting i was measured by ENGIS*roughness meter type 6102E tEngis Equipment Co., ~orton Grove, Illlnois? and ~ound to be 30-38 micr~ inches. The surfaee roughness of the comple-ted platinized and heat treated electrode was meaaured as ~4-28 micro ~nches.
. . The addition of lead acetate or other approprla~e .
. 25 lead salt to the platini~ g solution promotes the adher- . -ence of platinum to the tan~alum electrode, and is essen-t~aI for adherence of platinum black to the tantalum surface. ~ithout the prese~ce oX.a lead salt in the . platinizing solution, thc depos.Lted platinum blac~ flalces 30 of the surface of the tantalum. ~arious vol~a~es from about 3-2~ volts and ~aricd ti~e periods from about l/2 to 6 minutes were ound to be satisfactory for the platin-i7in~, processes. Six vol~s for six minutes was found j~ to be optimum from the vlewpoint of cost and eficiency, . 35 but is not critical for the proccss. ~ligher volta~es * T r a c~ e ma r k cause excessive pla~inum deposi~ on ~he elect~ode and lower voltag~s take l~nger times ~ orm a platinum deposit on the elec~rode.
~or good quality electrode~ ~ is desiràbl~ durlng the hea~ treatment 5~e.p to maj..Llt,ain ~lC ~urnace ~emper~
a,ure in the range of abont 105~-1150~ fo~ ~imes r~ngi~
f~m abou~ 30 minuteC to 1 hou~ Xt was ound ~ha~ below 1000C the pla~inum black does not ~dhere to t]l~ ta~alum e~ectTode and a~ ~e~perature~ higher tl-an about 1200C
the;platinum ~lack bu}n~ off.. '~he ll~nace ls ~nai~talned at a vacuu~ of 10-6 mm of mereury to pTevent oxidation - of plat~num or tantalu~, bue ~Tacu~ms ~utside thi9 ra~ge are also satisfactory. If desl~ed an Inert atDos~he~e could also be us~d during ehe hea~ ~reatl~g .step.
Superior qu~lity of the platini~ed and hea~ 1rRated electrode ~ver platinum plated ~leetr~des is f1lrther conirmed by the followi~g ~es~t based on the galvanic cell pr~nciple. The electrode consit~lting the posltive lead i8 attached ~o one elld of a 0~1 mA a~meter and a piece of tan~alum co~stituti~g the ~ega~ive lead ls attached to ~he other end of said ammeter. The e~ectrode arLd tantaluLI are placed in a beaker ~ontaining ~ Cl ~ater s;olueiorl and the rea~ on t~le a~meter ls ~soted.r This re~ding i~; knoe~n as a nc~ aull: readi~g~ The electrode 25 and tantalun are allowed to re~ain in place for o~e week.
Af ter the one wee~c period a pt ece of iron is connec~ed to the tantalum and ill~roduced into the ~Cl solution.
This simula~es the fault situa~ ion ~hen the gIass lining of the vessel is damaged and l:he con~ents are exposed 30 to the metal. A reacling is ~:alcen which lndicates higher current flow. In the simula~ed faul~c situation, l:he tests have consis~ently shown higher current readings for platinized and heat ~reated tantaluL~ electrodes than for platinum plated electrodes. The hi~her readings 35 ~ignify higher sensitiv~ ty of the platini~ed and heat ., ~ . . . . .
,,,, . . ~ . . .
- : . -- - ' -: . : . - :
. , ~ ,, treated ele~tr~des to the plated electrodes. One ~ueh exa~ple shoued the readin~s as follo~s:
F It Gu.-e---mA
~o ~ault Aft~r o~e After one 5 ElectrodeC~rr~ne =A ~ week 10 nin.
Conventio~al Plaeinum Plsted Ta 0.00 1.8~ 1~29 Plati~i~ed and ~eat Trea~ed Ta . 0~00 -5.46 3021 11) . . . .
/ ~hus, i~ should be appreciated ~hat the present inven~ion of platini~ing and h~a~ ~reating tantalum produces electrodes which ~easure a fault in a glass ~ined Yessel on a continued basis far mcre precisely than conventional platinum plated electrode~ even thnugh . the plated platinum coating ~g ehicker than the platinized ~d heat treated pla~num layer. Further~ th~ superior ¦-. p2rformance of t~e platini~ed a~d heat treated platinum ~: : layer is arhieved at a much lower cost than that of ~he 2~ platinum plating~ , ~: Although partic~lar e~bodiments o the present i~ven-:~: tion ha~e been dlsclos~d herei~ ~or purposes o~ explana-. tion, further ~odif ications or variatious thereof will be appare~t to those skilled in the art to which this invention pereains.
, : ~ .
: : , ' "
. .
:
: ~ . ~
~ . . ' ~ ' : ;- --~ ~ .
:: . : . .
., ~ .
~: ~ The solution ccntain5 3 g~s of chloroplatlnic acid, 0.02 :~
~ ~ gms of lead aceta~e per 100 ml of distilled water. The ; 30 tantalum core described above is connected to the negative lead of the 6Y DC power supply and the platinum strip is connected to the positive lead o the 6V DC power supply. Both the platinum strip and the tantalum core are suspended in the solutio~ in the beaker~ Only the .
area of the tantalum that is to be platinized is immersed ~: :
..~ , .
~ .
.~n the solu~ion~ The vol~age i9 th~n applied for ~ix mi~utes during which time the platinu~ black i5 deposited on thc tantalum core~ The tantalu~ electrodc ls ~hen care~ully removed ~rom t~e solution and ~lnsed with dis-~illed water. The platinum black deposi~.ed is dull blackand no~-adherent at this s~ag~a. The electrode ~s then placed in a rack and placed in a ~urrlace main~ai~ed at a vacuùm of about lO-6 mm of ~ercury a~d a temp~rature of about 1150C or l/2.hour~ This heat treat~ent re~ults i~ the platinum bei~ diffused into the surface of the tantalu~ ~hich exhibits a dull gray appearance Option-ally, the eantalu~ corè may b platinized and heat 'c~eated ~or a seco~d time in order to.form a more stable a~d adherent platinum lay~
It has also bee~ found that the quallty of the plat-inizing a~d heat t~ea~ed electrode is better when ~i~er sand is used ~or blastingt rather than coarser. The surace roughness of the ta~talum core after ~,andblasting i was measured by ENGIS*roughness meter type 6102E tEngis Equipment Co., ~orton Grove, Illlnois? and ~ound to be 30-38 micr~ inches. The surfaee roughness of the comple-ted platinized and heat treated electrode was meaaured as ~4-28 micro ~nches.
. . The addition of lead acetate or other approprla~e .
. 25 lead salt to the platini~ g solution promotes the adher- . -ence of platinum to the tan~alum electrode, and is essen-t~aI for adherence of platinum black to the tantalum surface. ~ithout the prese~ce oX.a lead salt in the . platinizing solution, thc depos.Lted platinum blac~ flalces 30 of the surface of the tantalum. ~arious vol~a~es from about 3-2~ volts and ~aricd ti~e periods from about l/2 to 6 minutes were ound to be satisfactory for the platin-i7in~, processes. Six vol~s for six minutes was found j~ to be optimum from the vlewpoint of cost and eficiency, . 35 but is not critical for the proccss. ~ligher volta~es * T r a c~ e ma r k cause excessive pla~inum deposi~ on ~he elect~ode and lower voltag~s take l~nger times ~ orm a platinum deposit on the elec~rode.
~or good quality electrode~ ~ is desiràbl~ durlng the hea~ treatment 5~e.p to maj..Llt,ain ~lC ~urnace ~emper~
a,ure in the range of abont 105~-1150~ fo~ ~imes r~ngi~
f~m abou~ 30 minuteC to 1 hou~ Xt was ound ~ha~ below 1000C the pla~inum black does not ~dhere to t]l~ ta~alum e~ectTode and a~ ~e~perature~ higher tl-an about 1200C
the;platinum ~lack bu}n~ off.. '~he ll~nace ls ~nai~talned at a vacuu~ of 10-6 mm of mereury to pTevent oxidation - of plat~num or tantalu~, bue ~Tacu~ms ~utside thi9 ra~ge are also satisfactory. If desl~ed an Inert atDos~he~e could also be us~d during ehe hea~ ~reatl~g .step.
Superior qu~lity of the platini~ed and hea~ 1rRated electrode ~ver platinum plated ~leetr~des is f1lrther conirmed by the followi~g ~es~t based on the galvanic cell pr~nciple. The electrode consit~lting the posltive lead i8 attached ~o one elld of a 0~1 mA a~meter and a piece of tan~alum co~stituti~g the ~ega~ive lead ls attached to ~he other end of said ammeter. The e~ectrode arLd tantaluLI are placed in a beaker ~ontaining ~ Cl ~ater s;olueiorl and the rea~ on t~le a~meter ls ~soted.r This re~ding i~; knoe~n as a nc~ aull: readi~g~ The electrode 25 and tantalun are allowed to re~ain in place for o~e week.
Af ter the one wee~c period a pt ece of iron is connec~ed to the tantalum and ill~roduced into the ~Cl solution.
This simula~es the fault situa~ ion ~hen the gIass lining of the vessel is damaged and l:he con~ents are exposed 30 to the metal. A reacling is ~:alcen which lndicates higher current flow. In the simula~ed faul~c situation, l:he tests have consis~ently shown higher current readings for platinized and heat ~reated tantaluL~ electrodes than for platinum plated electrodes. The hi~her readings 35 ~ignify higher sensitiv~ ty of the platini~ed and heat ., ~ . . . . .
,,,, . . ~ . . .
- : . -- - ' -: . : . - :
. , ~ ,, treated ele~tr~des to the plated electrodes. One ~ueh exa~ple shoued the readin~s as follo~s:
F It Gu.-e---mA
~o ~ault Aft~r o~e After one 5 ElectrodeC~rr~ne =A ~ week 10 nin.
Conventio~al Plaeinum Plsted Ta 0.00 1.8~ 1~29 Plati~i~ed and ~eat Trea~ed Ta . 0~00 -5.46 3021 11) . . . .
/ ~hus, i~ should be appreciated ~hat the present inven~ion of platini~ing and h~a~ ~reating tantalum produces electrodes which ~easure a fault in a glass ~ined Yessel on a continued basis far mcre precisely than conventional platinum plated electrode~ even thnugh . the plated platinum coating ~g ehicker than the platinized ~d heat treated pla~num layer. Further~ th~ superior ¦-. p2rformance of t~e platini~ed a~d heat treated platinum ~: : layer is arhieved at a much lower cost than that of ~he 2~ platinum plating~ , ~: Although partic~lar e~bodiments o the present i~ven-:~: tion ha~e been dlsclos~d herei~ ~or purposes o~ explana-. tion, further ~odif ications or variatious thereof will be appare~t to those skilled in the art to which this invention pereains.
, : ~ .
: : , ' "
. .
:
: ~ . ~
~ . . ' ~ ' : ;- --~ ~ .
:: . : . .
., ~ .
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method which comprises:
(a) forming a layer of platinum black by electrolysis on the surface of a tantalum or tantalum base alloy electrode;
(b) heating said electrode in an inert atmosphere at a temperature in the range of about 1050° to 1150°C. for about 30 minutes to 60 minutes, and (c) utilizing said electrode for the detection of faults in the glass lining of an iron or steel vessel by disposing said electrode in a conductive medium within said vessel, and measuring the current flow between said electrode and the exposed iron or steel surface at a damage area of the glass lining, whereby the composite electrode and exposed iron or steel form a Pt-Fe cell.
(a) forming a layer of platinum black by electrolysis on the surface of a tantalum or tantalum base alloy electrode;
(b) heating said electrode in an inert atmosphere at a temperature in the range of about 1050° to 1150°C. for about 30 minutes to 60 minutes, and (c) utilizing said electrode for the detection of faults in the glass lining of an iron or steel vessel by disposing said electrode in a conductive medium within said vessel, and measuring the current flow between said electrode and the exposed iron or steel surface at a damage area of the glass lining, whereby the composite electrode and exposed iron or steel form a Pt-Fe cell.
2. The method of claim 1 in which the electrode comprises a tantalum base alloy.
3. The method of claim 2 in which the tantalum base alloy contains tungsten.
4. The method of claim 1 in which the electrode in step (b) is heated under vacuum conditions.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US92381478A | 1978-07-12 | 1978-07-12 | |
| US923,814 | 1978-07-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146112A true CA1146112A (en) | 1983-05-10 |
Family
ID=25449301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000331382A Expired CA1146112A (en) | 1978-07-12 | 1979-07-09 | Method of forming a platinum layer on tantalum |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5514892A (en) |
| BR (1) | BR7904399A (en) |
| CA (1) | CA1146112A (en) |
| MX (1) | MX152071A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01301877A (en) * | 1988-05-31 | 1989-12-06 | Tanaka Kikinzoku Kogyo Kk | Production of electrode for electrolysis |
| CN108761297B (en) * | 2018-08-28 | 2024-05-10 | 重庆理工大学 | Dry-type air-core reactor partial discharge fault on-line monitoring appearance based on high frequency signal |
-
1979
- 1979-07-09 CA CA000331382A patent/CA1146112A/en not_active Expired
- 1979-07-10 MX MX17842379A patent/MX152071A/en unknown
- 1979-07-10 JP JP8656279A patent/JPS5514892A/en active Granted
- 1979-07-11 BR BR7904399A patent/BR7904399A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BR7904399A (en) | 1980-03-25 |
| MX152071A (en) | 1985-05-28 |
| JPS628515B2 (en) | 1987-02-23 |
| JPS5514892A (en) | 1980-02-01 |
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