DE1421368A1 - electrode - Google Patents

Description

UK filing priorities from January 28, 1959 and June 1, 1959 are claimed.

The present invention relates to a further development of the subject matter of the main patent ".., (file number

I 15 114 I7a / 12h). ■.

The main patent relates to an electrode structure, which comprises a carrier whose surface is made of titanium or a titanium alloy which has anodic polarization properties similar to those of pure titanium are comparable and with a part or the whole surface a metal. of the platinum group or a corresponding one Alloy is in contact. This metal can be platinum or

809802/0675

Be rhodium, and the alloy of platinum group metals may contain platinum or rhodium.

. The present invention now relates to such Electrode structure in which only part of the surface is covered with the platinum group metal or a corresponding alloy is in contact ..

According to the invention, the electrode structure has a support, part of the surface of which is in contact with platinum, rhodium or an alloy containing platinum or rhodium, and of which at least part of the surface, which is not in contact with the specified metal or alloy Contact is made of an alloy, the main regulation of which is titanium, to which niobium or tantalum is added, the niobium or tantalum being present in an amount of more than 1 wt .- ^ and where such a heat treatment took place that the phase structure of the alloy is such that the B phase content at the temperature of the heat treatment is at least 10 Vq1 .- #.

When cooling down from the heat treatment temperature, the ß-phase portion can completely or partially decompose, which is of the Composition of the alloy depends, the decomposition product hereinafter referred to as the deformed B component will.

According to a further feature of the invention, an alloy which has a higher breakdown figure (which will be described below) than commercially available pure titanium contains between 2.5 and 10 wt% niobium bed *. ·%

BATHROOM C & G '^ AL · / · 809802/0675

Titanium and impurities and has a retained or converted B-phase fraction of at least 30 vol.-Jf.

OemSss another feature of the invention contains an alloy which has a higher Ussohlagwert than commercially available pure titanium, between 5 and 20 Qew.- £ tantalum, remainder Titanium and impurities, and has a retained or converted β-phase fraction of at least 30 vol. - £

Although it is due to an increase in the niobium or Taatal content it is possible to have higher levels of Prosent in the pre-adn i-phase To achieve this, taking into account the high costs of niobium and tantalum, it is desirable to keep the proportion as low as possible « to use these ingredients. Oils effect of tantalum 1st continue in such a way that double the amount of this Blsaentes is necessary, as is the case with niobium, to obtain similar results, and when less than 2.5% of mlob is present are, is to achieve a corresponding S content necessary heat treatment far more difficult. From this Orund " Niobium is considered to be the preferred alloy constituent, in an amount of about 2.5 #, with the S-phase content sweekmSssig being at least £ 30, in order to achieve substantial benefit.

The e-phate content can be made up of retained »β-constituents, converted fi component or a mixture of the two.

The invention is in essence with reference to Figs.

80 980 2/0 67 5 ^{ΟΜ1Κί! Ϊ} "'* ^{/ #}

to 6 explains which graphical representations contain, the pelarization curve? of various alloys and Represent metals "

It is known that κ-enn at © ine Tltanelectrode a potential is applied, -the electrode polarized and little or ■ ksin current flows until the voltage rises above a value., which is referred to below as ifmehlagwert. If the voltage rises above this value, flows in StroiSj. and the fisktrods' corroded. However, if. A part of the electrode Is there a rush? .. Covering * made of platinum, for example, provided 1st, going through the electrode current of lower - ■ Tension through it. In such cases he doesn’t leave with'-one Topping 'verssfeene part of the. Electrode no® significant current = · " . quantity-durchpnd does not corrode either, provided that & s the tension remains below the envelope.

Although- dl «exact amount of the apportionment value - get closer respectively applied labor conditions changes, - this is with commercially pure titanium-in-oil-ldlS-songen about 1g. volt and increases * to 80 to 100 "volts in sulfur and phosphoric acid ·» solutions to. Fig. 1 now shows comparatively the © Poleri- ". sation curves of titanium, niobium and tantalum in 5% matrium

Di® Limitation of the voltage, which can be achieved without corrosion of the 'Electrode can be applied, is for certain' applications' - unfavorable purposes, for example if the SrlSsse des be « covered fells of the electrode limited.1st, if not with

■ BAD ORIGINAL * 809802/0675 '·. ^{m /} *

a covered part or a. Part of it will sizigetaucht in electrolytes must "and vena special Stromdiehten are required. Which require higher voltages than the Umsühl & gwertes, Such a case is b§i inside Catholic Sehutz * / © n sinftn grossea-diameter pipelines upstream, where In a special case a rod about 1 1/2 in length is used as the electrode, and only the tip of the disc is plated with platinum.

An Eetrachtv: '-;.; fV ':: · PolarisatioriC- ^ irTea iron Mio © and Tantalum (Fig. l) _ z & Xg, ·: ciess lÄ ^ ieru'ig ^ Ki' zvr ifiob οώ © Γ farifcal; ait fi tan PolaE'isa.tipßsk: ar ⁱ T®n erg € -fcaa kß ^ neii. Ale ss . ^ aös hShers potentials "may be sent, _s the, Uaaschlagwerfc for the alloy is increased, however tests have shown that this is not necessarily the case, unless an uneconomical percentage of niobium or tantalum is used. In any case, it obviously follows from the theory that only by alloying titanium with niobium or tantalum higher polarization curves are obtained than with titanium alone, that better results can be obtained rather than higher percentages of these alloy components, and tests have shown that in the absence of the B phase, this does not necessarily sutrifft. now that Job and tantalum are more expensive than titanium. what the economic feasibility of these elements prevented as alloy components ^

BATHROOM OBlGINAL 80 980 2/0 67 5 -'- '

can it be assumed that the problem of the avd & naens of an economically viable alloy for a certain potential only «? i? the question of the determination of the minimally effective?

of alloy component 1st.

Although it remains important, the minimum effective percentage of the alloy component? au embroider * because this is important in Hinbllek on the cost of the electrodes dureh ¥ Ersu © he Festge-H would splits, .d ^J s ^ s the per seat contentfresh d @ ® Legie-. rungshestandteil-only kritisciien one of sswei Factors is,

. 2 ^ eigt. the feraiac ^. & 'argebp.isse !, x ^ ob ^ I three samples

TI tail --iii ^! ΐ ^ Ei ob g © pi ^s öft μιιξΜ ^ ώ ^, um. their

rtah ay ^. 'i cf.f disspso Disg ^^ m dlf; Polarlsßfciia.flii .süblieh -reinscr fitaa, as it appears in the figures of the FalJ ^; . is. Each of these Fr & hen-m.irn® t \ ls anode in, a Srilsse of about 1.3 χ 35 x 15 bob used * which have been sanded ^ uai to give a smooth surface. » and were activated in an aqueous Belis bath, which contained 3% hydrofluoric acid and 20% nitric acid, before the samples were provided with a lacquer application, with about

3.2 square meters of the metal were released. The samples were exposed to a anodlsehen DC * where they were consisting ig, immersed in an electrolyte of a 5 ^ @ n MatriuiaohloridlSsung ■, and as the cathode is © commercially pure titanium in a large you 50 χ 12 s using 1.3 mm, where the distance between the electrical tracts was 38 ma * The curves are because »

BATH ORIGINAL

8098 02/067 5 _ _

by, get that the applied current gradually increases taking the values of the potential difference and the current at intervals of about 3 minutes.

Samples Mr ₁ , 1 and 3 were taken from different batches and they were deformed into the anode without any treatment other than mentioned above having taken place. would be heat treated at 80 ° C for 30 minutes and then seasoned in water.

The purpose of this heat treatment is to obtain an a- & O-phase structure in the alloy, which has between 30 and 40% retained or converted ß-ant @ l. It was confirmed by microscopic examination and X-ray analysis that the !! - The proportion of this sample was about 33% . . . '■'. . ■■ '.-,

FIG. 5 shows the result of fersuehs wide with three = · ren samples of the same! Alloy, "the $ 95 titanium and niobium $$ contains and which have been tested under the same conditions as the samples 1 to 3, as compared with the polarization curve of commercially pure © titanium. * * * Wärmehehandelt long sample No. 4 urde 30 minutes at 700 ⁰ C Sample No. 5 3Q minutes at 800 ° C and Sample No. 6 30 minutes at 900 ⁰ C and were in all cases:. Die.Proben abgeschreckt- in water.

It can be stated that sample no. 6 has a higher turnover rate at low current values. shows that the sample No. * 4

'BATH 80 3 80 2/067 5

the highest Uiaschlag * RERT at medium Stroniwerten, d _o h. those from JO to 60 Milliarap *, but that sample no. 5 has the best Aligestein values »'

■ Further tests were carried out to test the effect of the. Determine alloy components below; and, jbu this purpose, further samples of a similar size ^? eiee produced and these tested under the same conditions as the above 1 to 6. Sample No. 7 contained 10 $ niobium and 90 $ tantalum, Sample No. 8 ^, 32 $ lob. Balance titanium and 6SM Sample Nos. 9 2.5 * # Miob, residual tantalum, Me sample £ r> 7 was f "? ΤΦα-Φ-η at 7Q0 ° C, sample no. 8 jjg minutes öei 790 ⁰ C. .!. "ai sample No. 9 _30 Mirsuten ajar at 820 ^'5' * ¹ d ''*": _PIU: J: iarr'elt \ * ni> the pT tjben wtjr .-- s in Wass € *?. r abrc ^ t., ΐ? Ίί * ι><, ϊ ⁱ iflr - ?: ebf ⁱ ba: i-iit:.:; if, en were led, \ m fl-üefeelt .- * vjn * ti & ~ $ 3 % τη goes to% and -Sie ratur der WSnsie ^ fcaiHlUr-; Ä ^^ ei'V ^ ^{i::. ;} -'- h f., · et ^ r «·. W - ^ '^ hr ratio pm ier ll

The results i ^r ^ s <si ^ tii ^^ 'Yersufh «« inr Jx? Fig. 4 placed. Hieratiif- is real, ö &!? & Dei ^; tiissc-al: agwert tf? i. s & ntliohen three ProliyQ : js ? # <* "ser tlichfa gl" iii isfe with a current of 100 HmSorap., whether "raw 4Λκ an alloy with a high level of mob content affects l-critical properties at low current densities. Um Now the most effective amount of niobium to be determined, further tests were carried out with samples 10 to 13, all of which were worked and tested in the same way as samples 1 to 9 and

809802/0675

U21368

samples 10 to 1 contained> 0.01, 0.05, 1 and 5 # niobium, the remainder tantalum. The sample Mr. 10 has been tested in rolled condition, the samples 11 and 12 after a 30 minute heat treatment at 87O ⁰ C and quenching in water and the sample Hr. 13 after a 30 minute heat treatment at 800 ° C and quenching in water. The results of these tests are shown in FIG.

From this Figm ¹ »of the resulting Uüssuhlagwertes ₅ that the improvement hinsiehtlioh compared to that of commercially pure Tit & r * in these alloys is substantially proportional to the respective 1st niobium content. It is believed, however, that this is in large part because " the heat treatment required to obtain certain percentages of converted fi-constituent" becomes more critical at low niobium percentages (with little or no retained ß-content is present) and that minor deviations from the calculated heat treatment temperature result in considerable changes in terms of the structure and urason deposits. Εϊ "lowest prosenceous content of Job, which gives essential results in connection with the heat treatment within the accuracy limits possible with the Y & TBWßlmn ""seems to be 2.5 ^ su. However, these experiments show that any Pvosentgehalt of niobium but low 1st a certain advantage ätiv, lind dass'befriedigende benefits

■ '■ -.'- ■

tea! Mobshells of less than $ 2.5 can be obtained

809 80 2/0 67 5

1421388-

- ίο -

when the heat treatment is controlled within narrow limits. .

Fig. 6 shows the result of tests with alloys “containing tantalum” and contains curves from tests carried out with samples 14, 15, Γ6, which each contain 5 * 5 ”0.1 and 0.01Ji tantalum, Hast. Contained Ti tan, all samples were prepared and tested in the same manner as Samples 1 to 13. The sample 14 was exposed to a heat treatment at 575 ^° C. for 30 minutes and then cooled in water. However, the remaining samples were not subjected to any heat treatment. ,. '■

It can be assumed that the effect of tantalum, if it is present in larger quantities, leads to results which are comparable to those of niobium "provided that an appropriate heat treatment takes place in order to" produce an appropriate proportion of the ß-phase " f | j;. | p: $ | $ However, that the percentage of tantalum tt | i *! is twice as rough as that of niobium, in order to avoid it. ^: '"" .. ■■'. ·: " ^: "''

The theory on which the invention is based is that the, NlQb or tantalum are effective in two respects with regard to the impact value. t results, and if the alloys are thrown to a suitable treatment to ensure the presence of the β phase u

809802/0675

-lichen, i.e. as a fl-forming or ß-stabilizing agent, because of the presence of niobium or tantalum in a titanium alloy, in which the fl phase of the latter alloy formed by heat treatment is an improvement of the uraschlagwert is reached, which is far above the The value is to be expected from a consideration of FIG. 1 and is well above that obtained with the same alloy can be determined without heat treatment.

Through further observations it was found that the part of the formation of f1 is ineffective in calibrating if niobium or tantalum are not present. "These further)": experiments "- were carried out on a loan of fitarc-olybdenum alloys, soft di * «· desired? öa« «tj.etrukfcur aisfwtis« 2O _f . uiid.es has see $ <e% ® ± ffi _s

efees such alloy® ^ ^ ImlJ.ebif F% t ^ lsrii ^ eirte beeitae.n like t? h

Claims t

80 980 2/0 67 5

Claims (6)

Claims. 1.) electrode naefc Patent * .., (/ * "it a support, 'a part of which the surface with Riiodiitii or Eegierung of platinum or rhodium is in contact," characterized in that at least part of the Oberf läcshe, && i * not sfeskt with said metals and alloys in contact made of an alloy of ¹ EIR with Miob or tantalum beat honest _f ttobei the Mob or tantalum lii an amount of 1 wt meta * min <. -Ji is present, and the alloy in the way ttSrtsebehandelfc is _r that the Phaßenstrt-ü η .; * ■ of the same is such that the B-Hmsenanteü at the mung temperature isindesfcfeDS 10 ¥ ol ^ - ^ old * S.) electrode imeh ÜBspinzeh 1, dadfcapeb; gefcenn "calibrates _for the Legie2-u.iig Ktob entM £ if" "J.) Electrode nasps Äi / spi'iieii 2» df.-dtu? Eli gekenniseichnet, the Klob Ik eiaat »MeKge iron 2.5 to 5 QesP.-jS is available, 4 ») Elelctrode n-i ^ ii ifesprMeli 2 * dadureii gelrenneeichnet, because © Job is present in a set "Ton etsaa 2.5 Ge ^.» | ί and Containment of the retained or developed fit phase is at least 50 vol. Ji. 5.) Electrode according to claim 3, characterized in that the content of E-Pnaess that is withheld or itca-converted two 50 and 35 VoI, - ^ amounts * 6.) electrode naoh one of claims 1 Mf | » through this .808802 / 0675 : indicates "that it consists of an alloy which has a higher unsatisfactory value than commercially available pure titanium and which contains between 2.5 and 10 wt. - $ niobium"! test titanium and impurities and a content of retained or converted 3-phase of at least 30 Vol .- #. 7.) Electrode according to claim 1 to 5, characterized in that that it consists of an alloy which has a higher turnover value than commercially available pure titanium and which is between 5 and 20% by weight of tantalum, the remainder being titanium and impurities contains and has a content of retained or converted B-phase of at least 30 vol.-Ji. 809802/0 ^ 75