DE1483366A1 - Process for improving aluminum-tin alloys - Google Patents

Description

DR. ELISABETH JUNG, DR. VOLKER VOSSlUS. DIPL.-ING. GERH - "

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Patent application

P 14 83 366.0 "14th time J968

OLIN UATIiIKSOIi CttJätalCAL COEPORAtIOJf Process for improving aluminum-tin Alloys Additional au patent (patent application 0 9B9O VIa / 40b)

The invention relates to a method for the treatment of tin-containing alloys on aluminiumbaais. In particular concerns the invention a method for treating aluminum-tin alloys, to significantly improve their physical and / or chemical properties.

fäs was found to be when containing aluminum-tin Alloy according to the particular process conditions of the invention is handled, a significant and surprising improvement various physical properties of the alloy is obtained. For example and above all that results in method according to the invention a surprising and remarkable

New documents (Art 711 Abe. 2 No. 1 sentence 3 d «Am · ^ ***. _V. 4. β. 909808/0585 1

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value improvement of the anodon efficiency degree »The anode efficiency degree is a common term that indicates the proportional ratio of the weight of the consumed anode _p, according to Faraday's law, must be applied directly for electrical power generation to the actual total weight of the consumed anode. 15in higher efficiency means lower anode consumption by örtlicho corrosion and thus lower cost of kathodlochen Schutees _p elne longer life of the Anodeninaterials, less corrosion by-products such as z.ii. insoluble oxide hydrates and vas aero t off gas, and a more uniform delivery of galvanic electricity over the duration of the anode. From Berdera, improved leltar properties together with greater tensile strength and more favorable Weohaelatroia oil flow ratios compared to electrinohen aluminum inlus conductors are achieved when the alloy is used as an electrical conductor.

It has been found that the abovementioned verbosions are obtained when an aluminum-tin alloy with at least 90% aluminum and 0.04-0.5% is used for a period of at least 15 minutes, preferably from 15 minutes to 24 hours ütunden heated to a temperature of 54O ° -64O ° C, and anachlieenend ν at a rate of mindesteno 80 ⁰ C per hour to a temperature, η is at least 150 ⁰ O cools, whereby: las tin in solid solution in the highest possible extent is maintained. Preferably the cooling rate is so fast

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that the temperature is brought down to 150 ⁰ C within τοη 19 rfliwten or w «alger.

For the sake of simplicity daa is mentioned above be rewarded as "Hottogenieierungabehandluni".

They Gleiohgewichtelöeliohkelt the solid solution of meaning in aluminum is very low and less than Con t O, O27t at 228 ⁰ C, wherein eie further Rait reduced temperature decreases. The iiaxiaalluallchkeit τοη tin in solid aluminum is 0.105 * and occurs at 620 ° 0 «The tin is extremely effective in the formation of the desired disorder structure, the M-Type la aluminum oxide film on the metal surface, when the tin is used as a solid solution in the highest possible degree But particles τοη tin, which are atatietieohdldispersed and are not in solid solution, will contribute some to the desired disorder structure, but cannot necessarily affect the film for more than an ousoerot short distance of the smallest tin particles. Therefore, if the tin is not in the highest possible degree of solubility, the next best arrangement is the one in which the undissolved tin is divided into the largest possible number of small particles, each consisting of more than one tin atom.

It is known that the solidification of any alloy can increase some solubility of the dissolved clement in solid solution in the

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Lucungattlttel, results in a niohthoaogeneous distribution of desires which are known as "microabochoiduntf" or "coring" (coring) not. Jelbot the söhne11ate feasible in practice solidification can not homogenous fixed "Lösunc result · As another Üxtren would be a 90 slow solidification not practical, which allows to reach equilibrium. During the homogeneous tatsgrad About to change a wide range! canoe through the The special type of Gieooeno chosen is the unique ougllchkeit to the achievement of a uniform content of solid solution that the alloy is kept at a temperature at which the solubility is relatively high and the diffusion velocity is sufficiently large, among other things the equilibrium solubility uniformly through the alloy reach through au.

Even if the tiaximal solubility is reached at higher temperatures if it should not be theoretically possible, serve Condition to be maintained at K ^ uatemperator if the rhaeendiaßramm in equilibrium, the solubility of the old one Tea temperature decrease decreases. In practice, however, it is known that solid solutions that are supersaturated at barely any temperature are retained if the cooling is sufficiently rapid he follows. On the other hand, decomposition can take place on cooling, but if the cooling rate is sufficiently high, the temperature will increase the filled-in feilchen üur-nerot finely and well distributed,

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I have some O he sea experience like β. For example, the continuous or continuous molding process creates a structure in which a large proportion of the chin is in an oversaturated solid solution, which is based on the high rate of solidification in the case of moderately small cross-sectional lozenges and the continuation of the subsequent cooling to room temperature. However, there are still areas in which less than the uaxinal rod and also areas in which the tin overshoot is present in particle form. For this reason, iOrmgieselin ^ e galvanic properties approach those of homogeneous material and their use as such with some provision for optimal performance is conceivable . B. manufactured in sand molds or sour forasn, even show larger deviations from the ideal homogenized structure and require a separate homogenization heat treatment.

When the aluminum-tin lining is processed after the gloss should be, e.g. duroh rolling, pressing or forging the temperatures at which these operations and the sio et-

bsw- Anlafisen
what accompanying annealing / carried out is generally far below those at which the solubility has a maximum and decomposition occurs through the formation of precipitates from the solid solution

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Aad thenoo cooling but fixing the Virkuaeta Uaxinalluellohkeit necessary »including optimal galTanieoh · properties of the processed alloy samples.

Is also important that the invention is optimal. Combination is then obtained from high galvanic voltage and anode efficiency, nominal, daa tin on gleichnässigsten distributed and held in feeter Lorning in the highest degree "is but daae within a wide regions, deviations from this ideal condition still satisfactory, although sohlechtere .Eigenschaften shown Next In this way, some improvements in the galvanic efficiency or efficiency can be achieved through the addition of other alloy elements, as will be shown below.

The erfindungsgemäsoe method is applicable to alloys Aluminiuabasis at least 90 / aluminum and 0.04 - containing O _# 5J6 tin. £ a can of course many different types Legierungssusätzo be tolerated, which actually preferred wordene addition below the usual impurities normally found in alloys Aluminiunbasis, ζ.Bo silicon can in a * "close up to 0.105 · and i ^ isen up to O _t l $ 6 to be present.

For example, insoluble elements can generally be added to the alloy i.e. elements that have a solubility of less than 0.5 / i in! ester solution in aluminum. l) io total amount these insoluble elements should not be more than 0.5 '/ ·. These insoluble gels do not have any significant fluidity

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the Strooabfabe, as it is the solubility of the »Siaas is aluminum do not decrease, but they act as dual-phase cathodes and large amounts actually increased in the degree of anode action daduroh horrified that they promote local corrosion of the anode.

Soluble elements can also be added to the alloy. The soluble iSloaento can either be ale mesh or can be understood as a grid cycrenger, i.e. as a third additional element, which either widen or narrow the aluminum door Generally, smoothers stabilize the tin in the fixed solid solution and allow high galvanic StrSae can be sucked out of the alloy. Gltterau further can be in Jengen from 0.001 - 8? » be used. Typical Oitierau further and their usable amounts are, for example, magnesium from about 0.001-0.7.0 pounds, zirconium from about 0.001-0.3.0 pounds, wiemut from about 0.001 x 0.5 $, indium from about 0.001 - 0.5 and their .

In general, lattices prevent the tin from solidifying Solution forms, but small amounts are tolerated, as s. B. up to 0.01vi zinc, up to 0.002 * copper, up to 0.10 * silicon

and up to C, 055 * manganese.

The way in which the alloy is brought to the elevated temperature is not of decisive importance · 2s int but important, the alloy at a temperature of 54O ⁰ C to 640 ° C

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At least ** · 19 minutes do you hold up »** lse 13 outen ei» 24-hours · The preferred treatment tea period is 600 ° to 630 ° Q _{t the} most beneficial at 620 ⁰ O.

tfaoh the lliteobehandlungaetufe is cooled the alloy to a Teaperatur of at least 15o ° C at a rate of at least 80 ⁰ C per Ut and β echnell. Aa most favorably, the alloy is brought ^{to 150 ° C. within 15 minutes.} This is an essential feature of the invention. The rapid cooling is responsible for the fact that the kaxiaalatenge dee pewter is retained in a feater solution, generally to the highest degree, for example by quenching in Waaner, or that at least combined with the essentially uaxinal amount of tin in solid solution, a finely divided dispersion of As already mentioned, it is present and thus the surprising advantages of the invention are achieved at this stage Cause cooling, like thawing the alloy in cold water.

In addition to the favorable metallurgical structure created by the inventive homogenization treatment caused it was surprisingly found that dme on the surface of the alloy due to the action of air during the

action formed oxide promoting rapid activation

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Anode oegUaatlgt. The real activation is for some Application & application, for example ueerwaasarbatterlen. In hobea strives for tlaeee.

The invention is further illustrated by the following examples, example 1

An aluminum-based alloy with a fetch of 99.85: 4 AluBiniuB as well as pure tin and bismuth as alelegungssustttse was cast into bars in a conventional molding process. The resulting alloy had existed in the substantial aluminum based on the analysis after the casting a chemical Zuaamuensetsung 0.12> i tin and O ₉ 15 jfc vYiemut, wherein the üeet. Kinlge the Harren were then unteraogen different liomogenisierungebehandlungen they that were on Teeperaturen "wipe 575 ⁰ C and 62ü ° E crhittst and various" tents maintained at those temperatures and then quickly cooled to room temperature varies.

All treatments including the untreated and the homogenization abehondlunir Subjects were examined in various series of experiments for their galvanic properties.

Samples were machined from billets. the Samples for the determination of the galvanic properties were used Milled into pieces of 5 mm χ 5 mm cross-section and 75 mm in length.

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They were cheaiacb purified and "in" Jftlebe Ton 10 ββ "in""GalvanicZellon-Yerauoh" geaaes Journal of the Blectroohenioal Society, Volume 105, No. 11 Salt 629 it was subjected to Saatlioh determinations were in 0.1 η

carried out at 25 ° C ± 0.1 ^0. The galvanic stray was measured continuously, and the constant was bridged by a rflderatand τοη 10 ha, and the potential drop was continuously rewarded. In other respects similar to the probe body was tested in a modified test arrangement, the "Veruch mit Aufrücken Strom", where one liter of a 1.0 η MaOl-LO solution was used and a constant li tread was worth. 10 al / on was placed on the sample, which was used as the anode for 24 hours.

2
worked with a 10 cm steel cathode. Oleae current density was at least ten times greater than the la "galvanic cell experiment" and approached the conditions that nan achieved in a galvanic solid in the larger Juaestab, in which the cathode area is many times greater than the anode area and is low Efficiencies can be achieved if there is a tendency for the formation of spongy corrosion products.

τοη test specimens in electro-chemical combinations of the two types mentioned / result in a pretty great care. There are therefore individual sales results shown. Oiο number of coulombs that were generated within 48 hours in Galvanic cells-Yorauch flow, form an ilaaatab for the ability of the anode to maintain a! ichutzstroa and

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fear of the & xiaalnenge tin In solid Itteung or the la essential raaxitaalea iSinnraenge in solid solution and the rest Tin in finely dispersed forts. i) he all ttrosentsats dee Uirkungagrada is the anode degree · The weight of the aohwammigen products in the "attempt with the forced stron" looks at the amount of easily adhering corrosion product, the hollowed metallic particle contains and SU «low efficiency contributes«

The results are listed in the following table.

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OalY « hours 1071 Ge « 53 5 «? Verauoh bit imposed; 10 nA / oa " 14.6 8.2 current 52 53 I.
C.
I. 73 1023 1003 50 55 tßewioht O O 71 72 71 oioch ·: 900 1082 ■ et-} 64 61 Qeaaa the JchwaoDab- «
• OheiÄöHit rntt / an ο ο Total ^ 72 76 69 1123 914 54 54 16.8 1.1 1.1 Efficiency 6> 67 69 r Zellea-Verauoh 943 951 57 64 O 2.6 4.6 45 59 60 -C- Ln 892 839 Efficiency 68 it 3.3 4.1 3.5 71 71 67 OO Couloeb-yittfl 796 53 3 · 5 61 CJ • in 43 091 53 57 55 1.3 Kj, G 0.6 55 76 1013 997 57 54 4.1 O 11.4 74 71 cn 934 950 820 42 50 51 1.0 1.0 66- 70 on 1007 866 56 48 3.1 O O 69 835 905 62 O 67 in 757 2.7 70 N 793 59 O 909808 62 85 N 49 63 789 43 96 » 54 841 / 05: 900

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From the table above, β ion results in that the dl · optimal conditions XUr dl · homogenization are represented by the liitzo treatment for 16 hours at 62O ⁰ C and the subsequent disintegration in water. Uan proves that the dlo yormgieftelinge all of these deliver roughly the same galvanic energy * but with a lower current density, on average, produce a somewhat lower efficiency and with a high current density a noticeably lower efficiency for 6 hours, or slowing the rate of cooling by air cooling or furnace cooling, causes some loss in either galvanic efficiency or anode efficiency, or both. If the temperature is reduced to 605 C, 59t> 0 or i>71> ° C, i.e. temperatures below the temperature for the axial all-oil quality in solid solution for tin (6HO ⁰ C), a pronounced tendency to reduce galvanic is shown Jtrom and efficiency. Other pouring processes, in which the solidification level is lower than that of molding, also lower the galvanic current.

iteiaplol 2

An aluminum-based alloy of the following composition 0.30 ^ tin, Ü, 0u20> üiaen, less than ever ü.001 '> Silieiiua and Copper, the rest of the aluminum, was poured into 5 equal bars. To After casting, the ingots were treated as follows in order to maintain their i) loke from 7.62 cm to 0.02D era.

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A felt 260 ⁰ U to 0.695 oai toon tr «t. Eaa Haterie] was then quenched at 620 ° υ one at and β hoeoetalert and then in Vaeeer. Then Kaltwalsen et al. 96) reduced it to 0.025 oa Bloke. Λβ material was re-used on it

620 0 30 minutes hoaogenieiort and In Waeeer abeaohreokt · DIeaee Material was also remunerated and contained the Uaxia length 2Inn in fixed solution

Ingot B was treated in the same way as ingot A from the floodplain that the orneutc liomogenization level was abandoned. This muterial had the quality of the uc 9 &'- cold rolled down legion and contained the oxinal length of tin in solid solution.

Bullion C was homogenized 8 utunden at 62O ⁰ C and la Ufen old oinor Oosohwindigkeit of 55 ⁰ C per hour to 26O ⁰ C cooled. 3t was then waist at 260 ⁰ C to 0,635 on thickness slipped down ~ and then kaltgewalst to 96 ^ on ü, 025 om thickness. Diesee material had the Vergiltu; ^ ^ 96 to the kaltgewalsten alloy and the tin was "deposited from the solid solution at 260 ⁰ C Thus, this alloy containing substantially no chin in solid solution.

Barren D was homogenized out at 620 C a ütunrie at 260 ⁰ C at 0.635 ca Dioko heruntergewalst "and then quenched in water. The material was then cold-cured over £ 80 to 0.037 ea.

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rolled, annealed for an hour at 315 C, old air cooled and finally _{cold-rolled among other things £ 80 to O 9} 025 whether thickness. This material had the compensation of inter alia Büji cold rolled alloy, which was üinn solid solution at 315 ⁰ O filled. The alloy contained essentially no tin in solid solution.

iiarren S was treated in the same way as ingot i) with the exception that the second tempering was ^{renewed by a partial tempering at 12U 9} C for 3 hours. This material had * solution to the tin from the solid solution to precipitate the remuneration of un 80} "cold-rolled Legiorung and contained tin in solid Lb in the Uaximalmenge because the heat treatment at 12U ⁰ O was too weak.

With the alloys mentioned, test elements old silver Silver chloride cathodic in the manner of example 2 of patent application 0 9090. The experiment was carried out in such a way that that the values obtained are Utromdiohte-time characteristics and the cell voltage via a fixed external working resistance declarations. The maximum ^ current density, which is about a principal Maintain a portion of the entire period of service with the element shows the roughness of the anode material, The results obtained with the Veruchoelenenten are in the given in the following table, the Dlenente A-K the , Contain alloys made from ingots A - ii.

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A. Una la factor UJbuihj, UaxiwOMneV, WI 7.75 ι 7.95

B Stan is solid solution, Karl — I — ng · 7.1j 7.7b; 7, B?

C Jinn from t9MUT ^^^^ ß ^ ul% 4.4 i 4.4 j 4.4

0 JSiBn ana fted solution fills 4.25; 4.32 f 4.51

Itfgifcndise sol & en ecnlUißiiii daft »tion oilAen £? Orteii feei the application of the alloying material anode ifßä $% i ¹ Älöa ³ deS ^ iiteiE ^» Ur ^ eing H »rÄJflöalbe ^ ofe":

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Patent applications

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Claims (3)

Claim 1. Gate drive for heat treatment of an aluminum alloy intended for galvanic sweoke with at least 90% aluminum and a tin content of about 0.1% up to 0.5%, characterized in that the alloy smells at a temperature of 540 for at least 15 minutes ° Q and 640 ° C erbitat and then bit of a speed ron aindeatene 80 ° G per stand to «in · temperature below 150 ° C is cooled down» 2. Terfahren na oh Anapruoh 1, daduroh kenneeichnet, dafi the alloy is heated within 24 hours 3. Driving to Anapruoh 2, thereby noting that the dia Alloy is heated to € 00 ° 0 to 630 ° C. 4 Driving after testing 1 to 3, which is marked, dal the »alloy inside τοη less ala 15 minutes on at least 150 ° 0 is cooled. Repentance documents m 711 ^ _{2 N} ,, ^ d. fa «^ _{K 4} . ₉ . _1967} 909808/0585