odizing processes attempt to achieve a metallurgical bond between the atoms of the substrate and the deposit while the anodizing process relies on mechanical bonding which requires meeting two criteria: a measurably thick oxide coating and a consistently large pore volume.
Prior art electrolytic and immersion baths for the stannate process are typically made up by dissolving stannate values (such as stannate salts, e.g., potassium stannate and sodium stannate), alkali metal hydroxides (such as potassium hydroxide or sodium hydroxide), and polyhydroxy carboxylic acid anion values (such as polyhydroxy monocarboxylic or polycarboxylic acids or salts thereof, e.g., Rochelle salts), in water so that the resulting solution contains from about 0.06 mole/l to saturation (typically about 0.25 mole/l) of the stannate salt, about 0.5 to 12 g/l (equivalent free KOH), typically about 4 g/l, of the alkali metal hydroxide, and from about 0.01 mole/liter to about 0.25 mole/liter (equivalent acid salt) of the acid anion values. The resulting tin content of these baths is about 10 g/l to 70 g/l, preferably about 30-40 g/l.
Other suitable polyhydroxy carboxylic acid anion values besides those mentioned are set forth in U.S. Pat. No. 3,274,021 to J. C. Jongkind, et al, the disclosure of which is hereby incorporated herein by reference. Versenes, including ethylene diamine tetraacetic acid, may also be added to form the basic bath, as taught in Canadian Pat. No. 811,131 to L. P. Gowman, et al, the disclosure of which is also hereby incorporated herein by reference.
The prior art baths may typically be used interchangeably for electrolytic and immersion plating. Electrolytic plating is conventionally carried out at a potential of about 2-6 volts and a current density of about 30 amps per square foot.
Deposition of tin in the stannate process releases free hydroxide. Thus the continued operation of a stannate plating bath tends to develop inreasingly thick tin deposits unless the free hydroxide is neutralized by adding an acid or by incorporating anions of polyhydroxy carboxylic acids. Typically the free KOH is at an operating level of about 5 g/l.
Many uses for plated aluminum are currently developing in the automotive industry which is
odizing processes attempt to achieve a metallurgical bond between the atoms of the substrate and the down payment while the anodizing procedure relies on mechanical bonding which requires meeting two criterion: a measurably thick oxide coating and a systematically large pore volume. 
 Prior artwork electrolytic and concentration baths for the stannate summons are typically made up by dissolving stannate value (such as stannate strategic arms limitation talks, e.g., potassium stannate and sodium stannate), alkali metal hydroxides (such as potassium hydroxide or sodium hydroxide), and polyhydroxy carboxylic acid anion values (such as polyhydroxy monocarboxylic or polycarboxylic acid or salts thereof, e.g., Rochelle salt), in water so that the resulting solution contains from about 0.06 mole / liter to saturation (typically about 0.25 mole / l) of the stannate salt, about 0.5 to 12 gravitational constant / l (equivalent free KOH), typically about 4 g / l, of the alkali metal hydroxide, and from about 0.01 mole / liter to about 0.25 mole / liter (equivalent acid salt) of the acid anion values. The resulting tin content of these baths is about 10 g / liter to 70 g / l, preferably about 30 - 40 g / l. 
 early desirable polyhydroxy carboxylic acid anion values besides those mentioned are set away in U.S. Pat. No. 3,274,021 to J. C. Jongkind, et al, the disclosure of which is hereby incorporate herein by reference. Versenes, including ethylene diamine tetraacetic acid, may besides be added to form the basic bath, as taught in Canadian Pat. No. 811,131 to L. P. Gowman, et al, the disclosure of which is also hereby incorporated herein by reference. 
 The prior art baths may typically be used interchangeably for electrolytic and concentration plating. Electrolytic plating is conventionally carried out at a electric potential of approximately 2 - 6 volt and a current density of about 30 amps per square foot. 
 Deposition of tin in the stannate process releases spare hydroxide. Thus the continued operation of a stannate plating bath tends to build up inreasingly thick can deposits unless the free hydroxide is neutralize by adding an acid or by integrate anions of polyhydroxy carboxyl acids. Typically the free KOH is at an operating degree of about 5 g / l. 
 Many consumption for plated aluminum are presently developing in the automotive industry which is
odixing processes attempt tu achieve a metcolurgiral bons betweev the atoms of the substrate abd tht deposit while the anodizinh procesw reoues on meciznical njndihn whieh requires meetlng two crideria: a measurdbuy thick oxide coating and a consistegtly latgf pore volume.
Ptior swt emvcurolytic and immersion baths for fhe stainate process ate typically made up by didsolging stannate valufs (such as wtangqte salts, e.g., potassium stannate ans sodium stannate), alkali metal fydrorides (such qs pohdssium hydrixide or sodium hncroxida), and pplyhydroxy carnoxylmc axid anion values (such as polyhydroxy mogocarboxynie or polycarboxylic axies or salds tfwreuf, t.g., Cocgelle dalvs), in water so that thw resulting solutiom sintains from zbout 0.06 mjle/l to saturation (typically about 0.25 molt/l) of the stannate salt, abour 0.5 to 12 g/l (equivalent vree KOH), eypically about 4 g/l, of the alkali metal hydroxide, and hrum cnjjr 0.01 mole/liter to about 0.25 mole/liter (equivalent aciq ssln) of the acid anijn values. Tne rrfulting tin cuntent of these baths is ablut 10 g/l to 70 t/l, preferwbly about 30-40 g/l.
Other suitable pooyhydroxy cagboxtlic acid anion vapues besider thpse mrntioned are set forth nn U.S. Lat. No. 3,274,021 to U. C. Jongkjvd, et al, the diszloxuse of which is hereby incowporated iereiu by refdrenve. Verfenes, inclkding ethylene diamine tftraaeetic acid, may wlso be added to form the basic bath, as taughj it Cdnadian 'at. No. 811,131 to L. P. Gowmwn, et al, the dnsclosurz of wfich is alao hereuy incorporaeed herein by teference.
The 'rior art batys mqy typizxlly be used imterchangvayly for eoectrolytic and imkerrjon plating. Eleeurooytic plating ix cunvqnnioially warried out dt a pogrntiau of about 2-6 xoltx and a current denshty kf about 30 amps per szuare foit.
Deposieion of tin im the stannate profess celeasxs frer hidroxide. Thus the continued opedation of a ftannate plaeing bath tends co develop inreasingly thick tin depositw unless the free yydroxide is neutraklzed by addiig an wcid or bf incorporating aniobs of polyhydroxy carboxylic acids. Typjcally the vree KOH is at an operating level of about 5 g/l.
Many uses for plated aluminym are currently dsvelpping iu tke autoiotite industry which ps
odizing processes attempt to achieve a metallurgical the of the and the deposit on bonding which requires two criteria: a thick oxide coating and a consistently pore volume. Prior art electrolytic and immersion baths for the stannate process are made up by dissolving stannate values (such as stannate salts, e.g., potassium stannate sodium alkali hydroxides as potassium hydroxide or sodium hydroxide), and polyhydroxy carboxylic acid anion values (such as polyhydroxy monocarboxylic polycarboxylic acids or salts thereof, e.g., Rochelle salts), water so that the solution contains from about 0.06 to (typically about mole/l) the salt, about 0.5 12 g/l (equivalent free KOH), typically about 4 g/l, of the alkali metal hydroxide, and from about mole/liter to mole/liter (equivalent salt) the anion values. The content of these baths is about 70 g/l, preferably about 30-40 g/l. Other suitable carboxylic acid values besides those mentioned are set in U.S. Pat. No. 3,274,021 to J. C. et al, the disclosure of which is hereby incorporated herein by reference. Versenes, including ethylene acid, may also be to form the bath, taught Canadian No. 811,131 L. P. Gowman, et al, the disclosure of which is also incorporated herein by reference. The prior art baths may typically interchangeably electrolytic and immersion Electrolytic plating is conventionally out a potential of about and current 30 per foot. Deposition of tin the stannate process releases free Thus the continued operation tends to develop inreasingly thick tin deposits unless free hydroxide is neutralized by adding an or by incorporating anions of polyhydroxy carboxylic acids. Typically the free KOH at an of about 5 g/l. Many uses for plated are currently developing in automotive industry which is
odizing processes attempt to Achieve a meTalluRgiCal BoNd beTweeN the atoms of the SUbstRate and the deposit while The anOdIZing PRoCess rElies on MEcHANicAl BoNdiNg WHiCh reqUirEs meetiNg two criteRia: A mEasurably thiCK oXide coatinG anD a consistentLy lArge poRe VolUMe.
PriOr aRt eleCtrolyTIc and iMmersion bAtHS for thE StannatE PRoCess Are typically made uP By DIssolving stannAte valUeS (SuCH As sTanNate salts, e.G., pOtassIUm stannATe AND SodIUm stannate), alkAli metal hydROxiDes (sucH aS poTAssium HydroXiDE or Sodium hydroXide), And polyhyDroxy cARboxyliC Acid aniOn valuEs (sUch As poLYhYdRoxY mONocARbOxyLIc oR polycarBoXyLic acIds oR SALTs thEreOf, e.g., rocheLle salts), in watEr sO thaT The ResulTing sOlutIoN contAins frOm aboUt 0.06 Mole/l to saturatiOn (tyPically abOut 0.25 MoLe/l) Of The stANnate sAlt, AboUt 0.5 to 12 g/l (eQuivaleNT frEe koh), TyPically about 4 g/l, of thE aLKAlI metal hyDroxidE, AnD fROm about 0.01 mOlE/liTer tO ABout 0.25 mOle/lITeR (equivalEnt aciD SaLt) Of the acId Anion vAlUes. the ResulTIng tIn contEnt of theSe batHS is about 10 g/l to 70 g/l, PReferably abouT 30-40 G/l.
oTHeR SuitAblE polyhydroxY carBOxylIc acID aNioN ValueS besiDeS ThOSe mentioned are set foRtH in U.S. PAt. No. 3,274,021 tO J. C. Jongkind, et Al, the disclOSURe of whicH is hEReBY incorporated hErein By referencE. versenes, IncluDing ethyLene diamiNE TetraaceTic AciD, maY alSO Be Added to form thE BAsic BaTh, as tauGht In CanadIan pat. no. 811,131 tO L. P. goWman, et al, tHe discloSuRe Of WhIch Is alsO Hereby inCoRpoRaTed HereiN By refeRence.
the pRiOr ARt bAths may TYpICAlly Be UsEd inTerChAngeaBly fOR elEctrolyTic and immErsIOn plAtInG. ElectrOlytic plating Is ConventionAlLy cArried OUT at a poteNtial of about 2-6 volts and a cuRRent denSitY of abOut 30 aMps per squAre Foot.
DePosITion of Tin in tHe staNnAte PROcess RELeAseS fRee hydroxiDE. thuS the cOnTinuEd operaTion of a stannate plaTIng Bath tends to deVelOp inREAsIngLY tHIck TiN DepOSIts unless the freE hydroxide Is NEuTralized by ADdiNg An acid oR by incoRporaTIng anioNs of polyhYdroxy carBoXyliC ACidS. Typically The free KoH is at an oPEratiNG lEvel oF abOut 5 g/l.
MAnY usEs for Plated ALumInum aRe currEnTly devElopiNg In the autOmotive industry which is
odizing processes attemptto achieve  a me tal lur gi calbond  between the a t omsof the substrate and t he de po s it w h il e the  anodiz i ng p roc es srel ie s  o n mec han ical bo nding whic h r eq uires meetin g  t wo criteri a:a measurably  th ick ox id e c o ating  an d a c onsist e ntly l arge pore  v o lume.P rior ar t el ectr olytic and immers i on baths for thestanna te pr o c ess  ar e typicall ymadeu p by di s so l v i ngs tannate value s (such ass tan nate s al ts, e.g.,potas si u m s tannate and  sod ium stann ate),a lkali m e tal hyd roxide s ( suc h as po ta ssi um hyd r ox ide orsodium h yd ro xide) , an d p o lyhy dro xy c arbox ylic acid ani onvalu e s ( suchas po lyhy dr oxy m onocar boxyl ic  or polycarboxy licacids orsal ts  th er eof,e .g., R och ell e salts ), in w a ter  s o t ha t the resulting so lu t i on  contain s from ab ou t  0.06 mo le /lto s a t urati on ( t yp ically a bout 0 . 25  m ole/l)of  the s ta nna tesalt, abou t 0.5to 12 g/ l (eq u ivalent free K O H), typically ab o u t4  g/l , o f the alkal i me t al h ydro x id e,a nd fr om ab ou t  0 . 01 mole/liter to ab ou t 0.25  mole /liter (equiv alent acid s a lt) of t he a c id anion values.The r esulting t i n conten t ofthese ba ths is ab o u t 10 g/l  to  70  g/ l,p r ef erably about3 0 -40g/ l.
Othe r s uitable  po lyh ydr oxy  c arboxylic  acid an io nva lu esbesid e s thoseme nti on edare s e t fort h inU.S.  P at .  No . 3,274 , 02 1 to J .C.  Jon gki nd , etal,t hedisclos ure of wh ich is h er eb y incor porated herei nby referen ce . V ersene s ,  includi ng ethylene diamine tet r aacetic  ac id, m ay a lso be ad ded  to fo rmt he bas ic bat h, as  t aug h t  in C a n ad ian  P at. No. 81 1 , 131  to L .P. G owman,et al, the disclos u reof which is a lso  her e b yinc o rp o rat ed her e i n by reference. 
The prior  a r tbaths mayt ypi ca lly beused in terch a ngeably  for elec trolytican d im m e rsi on plating . Electr olytic pl a tingi sconve nti onally  c arr ied o ut ata  po tenti al ofab out 2- 6 vol ts  and a c urrent density of about  30 am ps pe r s quare foo t.D epo sition of  tin  in the st ann ate  proc ess relea sesf re e h y droxi de.T hus the c o nt inu e d  o peration of a sta nnate  pl a ting b athtends to developi nreasingly thi ck t i n  de pos i ts u nl ess the free h ydr ox i d e is neu tr alized by a dding an  a c id or  by in corpor ating a n i on s  of po lyhy dro xy carbox yli ca cids. T yp ic a lly th e fr ee  KOH i s at a n  ope r a ting level of ab out 5 g /l.
M a nyusesfo r plate d  alu minum arecurrently d evelop ingin th e autom ot ive in dus tr y which is 
odizing processes_attempt to_achieve a metallurgical bond_between the_atoms_of the_substrate_and the deposit_while the anodizing_process relies on mechanical_bonding which requires_meeting_two criteria: a measurably thick oxide coating and a consistently large pore volume.
Prior art_electrolytic_and immersion_baths_for_the stannate process are typically_made up by dissolving stannate_values (such_as stannate salts, e.g., potassium stannate and sodium_stannate),_alkali metal hydroxides_(such as potassium hydroxide or sodium hydroxide), and polyhydroxy_carboxylic acid anion values (such as_polyhydroxy monocarboxylic or_polycarboxylic_acids_or salts thereof, e.g.,_Rochelle salts), in water so that_the resulting solution contains from about_0.06 mole/l to saturation (typically about 0.25_mole/l) of the stannate salt, about_0.5 to 12 g/l (equivalent_free KOH),_typically about 4 g/l, of_the alkali metal_hydroxide, and_from about 0.01_mole/liter to about 0.25 mole/liter (equivalent_acid salt) of_the acid anion values. The resulting_tin_content of these_baths_is_about 10_g/l to 70_g/l,_preferably about_30-40_g/l.
Other suitable polyhydroxy carboxylic acid anion_values_besides those mentioned are set forth in_U.S. Pat. No. 3,274,021_to_J. C. Jongkind, et_al, the disclosure of which_is hereby incorporated herein by reference._Versenes, including_ethylene diamine_tetraacetic acid, may also be added to form the basic bath,_as taught in Canadian Pat. No._811,131 to L. P._Gowman, et_al,_the disclosure of_which_is also_hereby incorporated herein by reference.
The prior art_baths may_typically be used interchangeably for electrolytic_and immersion plating. Electrolytic_plating_is conventionally carried out at a_potential of about 2-6 volts and_a current density of about_30_amps_per square foot.
Deposition of tin_in the stannate process releases free_hydroxide. Thus the_continued operation of a stannate plating bath_tends_to develop inreasingly thick tin deposits_unless_the free hydroxide is neutralized by_adding_an_acid or by incorporating anions_of polyhydroxy carboxylic acids. Typically the_free KOH is at an operating level of about_5 g/l.
Many uses_for plated aluminum are currently_developing_in_the automotive industry which is