DE1621055A1 - Process for applying a coating of a yttrium compound or a compound of a rare earth metal to metal bodies - Google Patents

Description

The present invention 'relates to a method for applying a metallic coating to metal bodies, and in particular' a method of applying ilnes coating of an yttrium compound, or a compound of a metal of the rare Erdenλ on Matallkörperji in buckets ächmelz · fliissigen ^ alzbadjrdaa a fluoride of the coat bildenaen metal The procedure can be carried out with either or with the external emf.

A uniform ₉ resistant and well-adhering coating made of a yttrium compound or a compound of a rare earth metal lets you see aiaa

■ to-

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© ppossgusrOSrai PATBNfANWAtT Pß, BE1NH0LB QCHMIDT -

162TO53

Apply a specific group of metals or alloys when using current densities in the range vqb 0.1-30 A / dm. According to the present process, the yttrium or © in rare earth metal serves as an anode and is immersed in a molten salt bath consisting of an alkali metal fluoride, mixtures of such alkali metal fluorides and mixtures of alkali metal fluorides with strontium fluoride or barium fluoride and 0.01-40 mol $ > Contains yttrium fluoride or a metal fluoride of the rare earths · The metal body to which the coating is to be applied serves as the cathode. «Such a combination represents an electrolyte cell in which an electric current is generated when an electrical connection between the Metal cathode and the metal anode is produced «Under these conditions, the anode metal dissolves in the molten salt bath and is deposited on the surface of the metal cathode by discharging the ions, the deposited anode metal immediately diffusing into the metal body or the base metal and with the base metal reacts to form a coating consisting of a metal compound. The terms "tttrium compound" and "compound of a rare earth metal" and "metal compound" mean a solution or alloy between the yttrium or a metal of the rare earths Srdszi and the base metal 5 regardless of whether _s the base metal with the yttrium or - metal is rare e _r ä © i3 © ine iaterme "

© AD

■ · '■' IQiS 18/164!

metallic compound in; fixed ^ * stoichiometric ratios that form; as a former! formula dangest hurries to be: can. . ; -;.: "ν ^ _Λ

The rare earths are elements of the atomic number 57-71 "and consist of a ^ s Jianthans, Öer, Praseodym * ,; Neodym, Promethium, Samarium, Eu ^ opiunii G-adöliniüBi, ierbium, Dysprosium, HolffliTim, Erbium, Th-ptliuia ^ Xtterbiiim and l ^ etium. :

The solution \ mä -die; The rate of deposition of xftrium or an entail of the rare earths can be described as self-regulating, since the rate of deposition is the same as the rate of diffusion of the yttrium diffusing into the metal cathode: the fine metal of the rare earths. The Abscheidungsgesehwindigkeit can be lowered ,, by a resistance in the circuit is turned on * A / higher speed can be obtained by _t reacting a: voltage limited height applies to the circuit, whereby an additional - is generated direct current. -; :. ,:;

; There can be 0.01 * 40 or more MoI ^ yttrium fluoride or rare earth metal fluoride in the Torhanden weld pool. It is advisable to use concentrations of "these fluorides" in the range of 10-10 mol $ in a liquid salt bath. Higher concentrations of trium fluoride or rare earth metal fluoride, i.e. 30 mol $ or more, are only necessary if in a special case: i ! _f the usual Terdrängungsreaktiosi AELL in iithiumioneÄ 4ürch ittriumionen

101815/1648 / ^; V- _{SAD 0R1} ginaL

~ or solve the selt © n © n Erdeh are displaced, not instead of-;

. finds «

Those that can be used for the present process. ; Alkali metal fluorides -include the fluorides of lithium, sodium, potassium, HuMdium and cesium, as well as mixtures thereof. Zweoksäßigerweiee, however, is a eutectic mixture of hstrium fluoride. and lithium fluoride used as free alkali metal is produced by a displacement reaction ■ and potassium _t rubidium and cesium volatilize what bistet ersiehtlicherweise disadvantages. Lithium fluoride is most expediently used as a salt bath in which yttrium fluoride or a rare earth fluoride is dissolved, since lithium does not evaporate significantly at the prevailing operating temperatures. Mixtures of alkali metal fluorides with strontium fluoride or barium fluoride can also be used as a salt bath according to the present invention will" .

The chemical composition of the local salt bath is critical, which should be achieved with high quality metal coatings. Since & salt used should be as anhydrous as possible uad temin® contain impurities, or ⁴ would have to check s heating during SchmelEverfliiasigung easily troqkseja by bl S © © © clean the blank. The process must be carried out in an oxygen-free atmosphere, since oxygen interferes with the process flow

, "the anod @ $ m @ t & ll forms oxyds, so that no firmly adhering

Coating of the anode metal deposited on the metal cathode can be. The method can, for example, in one Inert gas or in a vacuum. The expression "Oxygen-free atmosphere" includes, öaS neither atmospheric * fresh oxygen or metal oxides in the liquid salt bath may be included. The best results are poorly achieved with chemically pure salts as starting materials and in that the process is carried out in a vacuum or in an inert gas is, for example in an atmosphere of argon, Helium, neon, krypton or xenon.

Occasionally it has been found that the chemically pure salts available on the market also had to be purified further in order to be able to achieve satisfactory results with the present process. This cleaning can be done by using scrap metal parts as the cathode at the beginning, with which some Xtar & hgäBge are carried out, either with or without cast-etched external tension, whereby those yenmixings are deposited from the bath j which are formed in the formation of metallic High quality coatings disadvantageous auawirkesi _D

As the Basiametalls will be to BeseliielituHg by the present process is ₅ kan & a metal of atomic number 4, 15, 21, 22s 23-29, 4O _S used 45-47, 72 rma 75 ° 79 '. These metals include "beispislss ¹ ©!. © ® Beryllium., AlumiriLum, Scandium, litan. Mangan ^ B ± aen ₉ Kobaldj ETiekel, ICupfgr _? Zirkoj3 _? Technetium, Rutheai-yia, HhoclitiBy Palladium ₉

υ υ · ■■ '! '* ■> i w a

Silver, hafnium;, lhenium, osmium, iridium * platinum and gold. Alloys of these metals or alloys which contain these metals as their main constituent, ie more than 50 mols, with another metal as a subordinate constituent with less than 50 mols, can also be used for coating formation according to the present invention can be used if the melting point of the resulting alloy is not lower than the operating temperature of the molten bath. “The alloy preferably contains at least 75 moles of a suitable bapi metal? "Better still are seven alloy components with 90 % of the base metal and correspondingly fewer other alloy components.

Although it is not possible to apply a non-fusible coating directly to metals that are difficult to melt, such as fanadium, chromium, mob, molybdenum, tantalum and tungsten, from a metal bond, it has been shown that this can be done with suction from a yttrium g or a compound of a metal € er rare

'Can you, if you can use the saelsable metals with a thin layer of a special metal, create a suitable solution for this _? spes £ figehen _f the forming metals count Bei ^ llitiai ^ ^ !! sssiniuia, .Bor lz ± w & 0 These as Koataktmittel SisM. ' . :: "S- S in the following as BerylliiamverMafiG..a £: Ll ^ Biizsium" bisfengs boron bond v.nü. Siliaium ¥ 6röi £ _IFER::; ^ cs Si © ÜbSFsugabildung with an- Bevylli.VM ^^ retty-.t-ATig

-ι a « η

■ according to the procedure as described in the Ü »S. Patent Ir. 3,024,175 the coating formation is described by means of a Sillaixün- • connection toag takes place according to the U.'8 · amendment patent Sr * 25 »630g the formation of a coating with a boron bond takes place according to US latent no Fler pending patent application with the serial Ho *. SSOD-791 "and the fitel zn® Aiaf attaching an oversize gias eiaor A on metal body ¹¹ "
It is still γόη. Advantage ₉ that

"Sater exclusion you Kotaleaetoff

since f Eolslenstof a very stable - forms ISstallkarbid mx £ d ^ r surface DER-metal catalysts Thode, .wodurob. tine more fber-

g is very worth seeing; and a badly adhering disfigured one! The carbon . - WMt sieSi aue i © a, liquid Saljsisaia dadureh removed ^ ta ^ Sai döiSaä operated as a lyte cell ^ is operated until it falls on the surface. the metal cathode no longer forms an earbid overlay »

Me fons the anode is. Looks critigah # For example, a rod made of pure yttrium or a metal of the seltepes Eröen can be used as an anode w @ Täen ₉ or, also metal chips € es yttrium or the rare Mräeia ₉ di © ψοά one porous metal container _? for example from; · Kiob or fant @ l, imsshlossen sine. « JkIm metal anode can also be used gin® absehirat © carbon anode ₀ In addition, © ine 8n6ere'3Q0C can be embossed *, as will be explained in more detail *

BATH ORIGINAL

1Q9618 / 1S4S

For a reasonable coating ^rate: is and to the diffusion of yttrium, or a metal of geltenen earth in the surface of the metal cathode in order formed to ensure ₉ a of a metal compound / existing coating _s to the process at operating temperatures in the range of about 500-1100 ⁰ C. Preferred operating temperatures are between 900-1100 C.

The temperature at which the process of the invention is carried out depends to some extent on the particular molten salt bath. If, for example, low (temperatures of about 500 ⁰ G are desired, a eutectic made of sodium and lithium fluoride can be used ο the operating temperature is in the range between 900-1100 ⁰ O », Mthiumfluorid is preferred as the molten bath =

If an electrical circuit outside of _{the fusible is established 9} by connecting the metal anode to the metal cathode via a conductor, an electrical current flows without additional external emf. The anode produced by dissolving in echmelzflüssigen salt bath electrons and ions äes anode metal, the electrons flow through the external circuit _s is formed by the conductor and U 1οώ <3 the AEiode migrate through the molten bath to the metal * · "on oils of the coating applied be 'shall} where * the ai @ Metalliö ^ gsu eatladea and dadureh a' coating of a metallic varnish arises. The stream ka »ö with agemessea? / Erdesa _f what you can see on uez metal; _;

109818/1848

Cathode deposited metal can calculate the see converted into a layer present as a metal compound « When the surface of the zn "coated article is known the thickness of the metallic over- « train so that a precise control of the process, is possible, through the any desired thickness of the metallic » Coating can be achieved o

Although the procedure can be carried out in a satisfactory way without additional external MM _? there is the possibility to apply a low voltage ₉ when a constant current density is desired during the reaction and wenii the Abscheidungsgeschii / _s should 'be increased iacligkeit of the coat-forming metal that while the rate of diffusion of the domestic the Me-fealikatlnode eiudiffundierenden metal ions to be exceeded without allowed. _o The additional amount should not exceed 1.0 7 and generally be in the range between 0.1-O ₅ S ¥

Since the DiffusioBsgeschwindigkeit τοη fttriuin and the rare E ^ the tind in, cüenenden as cathode Me-talllrörpei · depending on the nature of the material irariiert xm & tob d © r lemperatur the thickness to be formed by coating depends _v, the upper Gr © nzea of the vevwenä®t & n current density ^ Abscheidungsgesehv / in & igkeit fi © s the tfboffsng MlösndQB M must therefore always be set w © 3? d @ a _p flau dia gsQChii / iadigkeit des? ± the Metalllsatisecic Me-feallteilohen aicbt TXbertselwtt-b®® WiX n ¹ Sf so oin

free * quality guaranteed "remains" the maximum current density for a good coating as a metal bond is "at 30 l / dm _s if the process is the same as before.

! Temperature range _{- expires o} Higher current & ielirfeeii can sometimes be used ? a coating heräsiiis-fcelleh, fell * not only from the yttria compound 'or the metal association of the rare earth consists * but also. The diffusion layer contains an outer metallization from the overlapping material. -

Very low current density a (0.01-0.1 i / dm ), as used when the diffusion levels are correspondingly low and when very diffuse surface glazing or a very thin coating is to be achieved "- only then expedient if a high iQneaakcrassexitra- • feioa (more than 5 ^} of the metal forming the coating "or aMi? --- a high concentration of Jiithiuin (about 1 $) in the smelting bath forltegto- You can composition of the Diffusionilfeexaiigs; be changed by the current density TS ^ you iiert _s so mad ■ T ^ rschieSenen Versuohsbedingunges -untersciaieäliche and Äs ¥ @ rsehiedeHe _{erw.endungsaweGk;.???} s appropriate - Susanneaseiiztingen 'won SiffmsioiasübersiigB "created werSea Mönmezi * -jfe general, litgt ^ ie; StromdiGhte for eiö © a & u® © ims ^ 'Hetallver-

^: ■ - '■ - "

Muämsg; existing Ibergiig good quality mTlmchsm 1-10 Λ / dm

Wää : swio? for ii® hier.ang@ft&rten b © wxmigi © af

iasi. -fts? nickel

or as soon as "where the diffusion takes place very quickly, because / these elements have an extraordinarily high reactivity in the formation of isteraetallic compounds.

When an external MK is used, the DC power source, such as a battery should the like barren, "are connected with the outer Utromkreis in Oerie so that the negative Slemme of eggs su .beschichtenden metal cathode and the positive terminal switched on at the anode in -the external circuit , becomes »In this way the tensions of the two gpaunuzHgsquellea add up algebraically.

Optionally, measuring devices can be switched on in the external circuit to control the process, for example Toltmeterj Amper © a @ ter _s Tifiderstänü © ₉ time switch etc.

33er metal body _s which siseh Sem vosüegeaäeai Yerfhren is provided with a coating of a HotallverMactisBg <gja, should after the end of the YerfaiaSon si ^ sälieh ssBüh also the molten Salsbad sntfeszjt v / srden ₀ TiJensi des? beschiciatgte metal body with the sehaelsfliissigen Salsbüfi is3 contact remains j occurs siue Yerdrängungsreeiktion AIIF, "in the CLAS yttrium or Sletall the. salt '@ ADN SrfI © J2 ± m ffi ©-metallic coating with the Älkalimetallfluo ^ ld reacts _p m äaB free alkali metal and Yttrlniaflaiszlä Mqt IIupe-iM ü®t ancient earths

"Sie iTOTli & genil® Beauä ^ oi ^ ttzig &<$ ® Yeffebraaa beaog -" on a carrion from Yttsriaia © äer sin.em! © tall the rare

18/1546

Grounding, whereby no external voltage is applied. Instead of the yttrium anode or the rare earth anode can »however also use a shielded carbon anode * .be »where the necessary for the operation of the electrolytic cell EK is applied as an external voltage.

Experiments showed that when the coating formation with an yttrium compound or a compound of a metal dfer rare E _r of the from the fluorides of these metals, the limits specified in the above should be met for the current density * However, if a Zohlenstoffanöde used wirdj must the applied voltage 1- 3 V can be increased »If: the -. Carbon anode has too small a surface, the voltage can of course be even higher.

"If an iCarbon-off anode is used, carbon tetrafluoride is produced at the anMe, which escapes as a gas, and the metal ions migrate to the cathode, are deposited there and diffuse into the lasismetall and react with the base metal, so that a coating of a metal compound creates "If Kohlenstoffanöden ₉ would, of course, of! time to time yttrium or the rare Pluorid e _{r f} the werä.en replenished otherwise the melt at these serving for coating ion impoverished used for longer periods of operation....

The following examples serve to explain

Verification of the invention. All given ratios are true; cushions, unless expressly different sizes _; , are given *

109818 / 1BA6

M21P55

Example T ■■ --.-....- ..:. ":;'

lithium fluoride (6810 g) was filled in a container made of mild steel, yon a diameter 15, Z em and a height of 45.7 cm possessed (6 "χ 18 ^M), and was provided with a Monelauskleidung whose diameter 14 effi and height was 50.2 cm (5V2 ^fl χ; 12 "). The container was in a; Brought an electric furnace whose diameter was 16.5 cm and height was 50.8 cm (6 ¹ JZ " χ 20"). The container had an upper edge into which a cover plate made of Hickelstabl was embedded. The cover plate containing a passage for cooling water, two openings with a diameter voii 6y 35 cm (2ßf2 ^tt} - for two serving as electrodes G-laazyliiider and "two holes of 2.5 cm diameter (1 ^ir) for a fhermoelement and Gas supply tube (gas bubbler ') or a? For connection to vacuum. The container was evacuated and lithium fluoride was melted. Argon was then introduced into the container; and tttrium fluoride (91 g) was added to the molten lithium fluoride. A graphite anode with a diameter of 0.15. 63 cm ( ¹ 1/2 ") was shielded by a Monel grid, - so that -> no carbon particles should get into the molten bath, it was immersed 10.1 cm 4") deep in the melted lithium fluoride. As the cathode, a Hickel-tredfen served with Abraessungen 2.5 χ 12.7 3c 0, -05 cm (1 "χ 5 per .Q; ^D2?) | The up: quite preserved temperature was 1000 ⁵ Oc The further data regarding time, voltage and current intensity are given in the following table.: ^! · λ. " _

■■ '' ■■ - ^{":; ;} -. - ^.::>: ■ "'. :. ^:; SADQRiQlHAL '■

; 10 9S18 / 15 46

Tabel I. Time (m in) anode voltage ^ (Y) ί .Q- +0.04 -.1 +1.90 1,1 ': ■■■' +2.10 31 '+2.50 32 +0.82 Itromsti 0.0 0.5 0.5 0.5 P ₁ O

The Bickel cathode showed a weight increase of 0.014 g (theoretical yield 0.270 g for the reaction Y + 3e - ^ Y ⁰ ) and showed a dull gray earbe. An X-ray analysis showed that yttrium was present in high concentration on the seal surface. Example 2

In this example, instead of the shielded carbon anode from Example 1, an yttrium anode was used.
The procedure was as in Example 1 at 1000 ° C with a
Nickel strips carried out as the cathode. Table II shows the results at low current densities.

Table II -

Time (min) anode voltage (t) Current density (A / dm) _M.

0 -0.410 0

1 -0.300 -0.6 Power on 25 -0.150 '0.6

4'7 -0.100 0 _s 6 Power off

47 * 10. -0 _c ^ 10 0.

48 - -O ₅ 260 0 sample taken out-

101818/164

The Ficfcelkathoäe recorded a weight gain of 0.129 \ g of yttrium * corresponding to a yield of -6OJ6, and had a coating of ice xttrium compound ^ i ^ a thickness of 2.5 * 10 ~ "* cm (1 mil). In the negative polarity of the anode it can be seen that a sweeter voltage was applied.

labelle IiX provides you with the results of a series of tests at 1000 ⁰ O and a high current density with a sealed cathode and yttriumano & e «

Table ΪΙΧ

ZeitjjGtin) Anode voltage (?) Current density (A / dm ² ) Power switched on 0 -0.420 0 Electricity excluded ; 1 +0.320 10 .4; ■ - ■■■ +0.56 ;. "■■ 10 - ■ Sample taken out 4s 1O-. '"■ - -0.16 - 5 ■■; ■■ -Ö, 20

The Hickeüathoäe had an expansion of 266 g of yttrium, which corresponds to a yield of $ 91, and had a coating with a thickness of 5 ^e 10 cm (2 mil) »

It was found that those with a yttrium connection coated samples had to be removed from the container immediately after switching off the current flow, since the Yttrium of the sample, if the sample with the Mtliiumfluoriäbaä stayed in contact, went into solution and displaced lithium ions. As proof of this, two with an yttrium, , compound coated Sickelprobsn different lengths in

109818/1548

bath

immersed in a bath. The first stayed in the bathroom for 60 minutes and the second 10 minutes. The sample that remained in the bath for 60 minutes lost 0.062 g, whereas the sample that remained in the bath for only 10 minutes had lost ^{0.02 v g.}
Example 5 "

■. With various bookings with 850-1100 ° c and with Hickel strips as cathode and a shielded carbon rod As an anode, it was found that the current density and the concentration of the xttrium fluoride have a strong influence on the formation of the coating, with an yttrium compound had, as Table IY shows, '- "■

■ '"- ■ ^: table IT

Concentration
tion. iQlf * Anode voltage (V) - + 3t 5 Current density (A / dm Current-
effective
) degree ('ρ) * & ■ /% .: +0.5 ; - '+3 | 5- 0.05-1.0 15th 0.59 ■ '.: " +0.8 > +3.5 0.10-2.0 25th 1.12 ■ -
. . - - + OjS - +3.5 0.10-2.0 35 1.79 +0.8 «· +5.0 ^; ■. ■ -; ■ 0.10-2.0 • 40 +0.8 ■> +10.0 0.10 - 2.0 45 2 ** 31 ^v _: +2.0 5 - 10 90 +3.0 5 - 30 > 95

': For all test series given in table IY

smooth / gltosp & äe overgrouds from an ifttriual relationship

"was at

Concentrations and current services. The coatings were very * "pliable and radiate tolerably hard (600-900 degrees of hardness Knoop). An analysis by X-ray showed? That on the surface of the provided with a tfberzug strip both Mekel and yttrium _s was present is seen resulting in that the yttrium diffused very rapidly in the nickel ,, showed Crystallographic studies to which an intermetallic compound performing coatings that at low current densities mainly YNi, _- emerged and at higher Stromdiehten YM ₂ ■.
Example 4 ■ ■

There are the results of siad summarized in the following table ¹ different test series for coating formation in a lithium fluoride molten performed _t *

BAD ORiGJNAL

! Table Y

Current- Weight- SItrom-Z4 theiite increase & e effect- (min) A / cbB ² g degree n &)

Description of the coating

Si-Samel
! Egg-Ifunel

1050

900
900

900 32
900 2
900 5

900

900

900

2 JO ₁ O 0.705

/ 2 16.7: 0.140

16 2.1 0.105

1 0.058

23.6 0.158 9.4 '0.147

20 1.2 0.009

8 5 _S 1 0.146

U,

Ο? 042

0.081

96

95.5

39.4

43

67

5 40

57 12.7 * 10 " ⁵ Dieke, shiny, - &Lat1;, tdegsam ,, hard (6.00-900 EM)

2.5 ⁹ IO ^ ³ cm rail depth ©

1.78 «10""'θΣα beading, glossy» smooth, sam, beard (500-800 KHS)

1.01 x 10 " ⁵ cm slice die
2.5'10 "^ cm rail thickness

2.5 * 1Q cm thick, shiny, smooth, very ■ flexible, hard (500-800 EM)

0.25 x 10 "" ³ cm layer thickness

2.5 x 10 ^ cm thick, shiny, granular, pliable, soft, mainly galvanic layer, little diffusion layer

0.5 * 10 'cm thick, shiny smooth, very' flexible

about 0.25 »10 ^v em Dieto, glängead ,, smooth? Flexibility softer than it is, hptäbl galYanisohe layer, little diffusion layer

^ i. ·; ■■■ / 900; · Pslladium 900

y 900 with sllislooi-.

coated

(ffortaet gang)

Strom «, (S-eW .-, '■■;' ■ '' Strpm-

12th

1

3.3 32

0.018 0.02?

100

100

· 36 cm;

2.5 x 10 ^ cm thick, shiny, smooth, brittle, hard (approx. 500 KHN)

1.27 · 10 "* οΐα thick © * shiny, smooth, fairly pliable, soft galvanic ittrium surface over hard triple layer

Uas molybdenum was previously coated with a silicon compound according to the Abändestingspatent Ho * 25 »630 has been provided. . £ * ß »

- Example 5 ".

Instead of the yttrium anode from the previous examples "a carbon electrode was used and
various other metals by the same general procedure with a coating of a yttrium compound
Mistake. The results are summarized in Table TI.

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* ■■ - ■ - '' C w P3

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in i * οι W.

mm m.

if

rf: O '- i - "''- * f ^: ' ft: je». qflO --- SS-S ?. ". ' So-ill

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toi re / 1 m

1821055

Example 6

I ξ #iner contained in the apparatus of Example 1 fcitiJiumfluorid-Scbmelze (3178 g) was "110 g Gadoliniumtrifluorid added. A shielded Grrapbit anode with a diameter of 0.63 cm (4 ") was then immersed through one of the openings 10) 1 cm deep (4") and a strip of hickle with dimensions 15.2 1.9 0 .05 cm (6 «χ ^ 4" χ 0.02 ») introduced into the weld pool through the other opening as a cathode * The operating temperature was 945 ° C. The results are summarized in the following table»

Table VII

Time (min) Anode voltage (7) Current density (A / dm) Power switched on O ·, , -0.07 0 t +3.70 3.0 Power off 5 +4 _f 10 3.0 Sample taken out 31. +4.60 3.0 32, +1 _t 77 0

Di «ific & oil coarse who with a black material btdtckt, the sieve was easily washed off. Underneath it showed *, gray, pliable coating with a thickness of the iitclcel ^ athode recorded ei »·

of 0.835 β compared to a theoretical value of

Sd ⁺ ? + 3e -4 aö °> t wa »#iser Aua-

■? Oa 43 ^ "esitaprmch, Si" · Aiialyss pit

Seven different line cathodes were then used for 5 ampere hours to remove impurities from the molten bath. Thereafter, the stripes showed a shiny, smooth surface and the yield had increased to 70 fs of the theoretical value.
Example 7

Instead of the carbon anode from Example 6, an adolinium anode was used _f waä a Miekestripe with the dimensions 10 _y 1 χ 2.5 x 0.05 cm (4 ^? * Χ 1 "χ 0 ₃ 02") served as the cathode at an operating temperature of 1000 ⁰ C. the results are summarized in the following Talselle.

! Table VIII

Anode voltage (V) current density (A / äm)

töjö current switched on 1OgO current switched off 0 press removed The Miekel & athode recorded © an increase in weight of O _s 628 g compared to a theoretical Y / ert γοη 0.652 g and had a coating with a thickness of 5 ⁰ IG ^ CBi * the gissend, smooth , was hard and pliable, ■ When using a ffickellcathode "at lower

StroacLiejbten (1-3 A / dm ² ) a yield of $ 40-50 was obtained.

ι
23an] 5 a, ''

Gsd & Xinium or carbon anode and. a metal cathode under ■ the conditions of the following table Trerwen, det ·. · ■ ..

BATH ORIGINAL

O -O ₅ 250 1 -0.540 2 +1.03 6th +1.02 6s10 -0.16 '

ICetalI

Soon

Ct)

Moselle

(D

, "Anode current weight, - 'current

• Time tension density increased. wirini *

(min) (?) (A / dm ² ) (^) grad, ι Description of the coating

tOÖO

900

900

1000

Zircon

on

+0.42

+ 0 * 75

0.11-0.60

4-1.0

+0.4

4-0.3

3 +1.15

5 1.85 vanadium
chrome

+0.23

0.159

15th 0.542 83 8th 0.064 8th .5 0.60 90 12th 0.149 38 8th 0.095 29 12th 0.600 77 20th 0.231 15th 0.7 0.040 14th

1.27 x 10 "" ^? emj shiny, smooth, 'pliable, quite hard

5 »10 ** ^ om; shiny, smooth, flexible, hard

0.76 ^# 10 "^ cmj shiny, smooth, pliable, hard

Melted. Surface, shiny, soft, pliable

5'1O ~ ^ 0mj shiny, smooth, soft, flexible

1.27 * lO ^ cmj glossy, smooth, pretty hard, brittle

2.5ΊΟ "" ^ ⁵ cm? shiny, smooth, quite pliable and hard

1.27 * 10 "cm; gray, smooth, pliable, soft, Gd-Schioht over inner layer

0.5 * 10 cm outer cover j shiny, smooth, hard, more than 38 ' cm soft inner layer; flexible overall / covering

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Table IX (setting)

Anode current weight

ElectricityMetal

Temp.time voltage density increase effect ⁰ C (min) (V) A / dm ² (g) degrees ($)

Description of the coating

Boron- ^ ¹ ^ 1000
link ·
on ti camel

Scandium 1000
link
on Uickel

+0.33

-0.38 to -0.08

4.0 0.153

0.75 0.864

47

88

1.27 * 1O "~ 'em outer layer, shiny, smooth, very hard, more as 3.8 * 10 ~ 3cm inner layer; flexible overall cover

3.8 x 10 ^ cm outer layer, glossy, smooth, very hard, more than 2.5v10-3cm inner layer, quite hard - flexible overall coating

(1) Gadolinium anode -

(2) shielded carbon anode; -

(3) The Mob obtained by the method of the copending application, Serial Ho. EDCD-749, entitled "A method for applying a coating" of a zirconium or hafnium compound to metal bodies ¹ ^ a coating made of a zirconium compound.

(4) Mckel obtained the procedure from copending application, Serial Uo. SDCD-836 with the title "Method for applying a UbBi-ZUgS ₁ from a Mckelverbindungen, cobalt compound or iron compound on metal bodies? ¹ a coating from a seandium compound.., .- ·

CT)

ro ■ _ *

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cn

Claims (12)

Patent application »Process for applying a coating of a yttrium compound or a compound of a rare earth metal to metal bodies. PATENT CLAIMS 1. A method for applying a coating of a yttrium compound or a compound of a rare earth metal to metal bodies made of a metal with (a) a melting point of at least 500 ^° C. and consisting of at least 50 mol # of at least one metal with atomic number 4, 13 , 21, 22, 25-29, 40, 43-47, 72 and 75-79 and (b) consisting of one of the elements vanadium, chromium, niobium, molybdenum, tantalum or tungsten, which is coated with a beryllium compound, boron compound , Aluminum compound or silicon compound is provided, characterized by (1) producing an electrolytic cell from the metal body as 109818/15 4 6 Patent attorney · Dipl.-lng, Martin Licht, Dipl.-Wirtich.-lng. Axel Hanimann, Dipl.-Phy ». Sebastian Herrmann " 3 MÖNCHEN 2, THERESIENSTRA8SE SS · TtUfom MlJOJ · T «l« oramm-AdniMi Llpalll / MOndwn ^{α /} ί0 lankvtrblndunetm Diutich · Bank AQ, Branch · MOndnn, D «p.-Kai« · ViktuallenararM, account no. 70/30 «3» layir, Varalnibank MQnditn, Zwdgil. Otkor-von-Mlllir-RIno, account no. MI49S · Poittditdt-Konloi MDndwn No. 143397 Oppcnauir lOroi PATINTANWALT DR.R8INHOLD SCHMIDT <H $ l Cathode, which is connected via an external circuit to an yttrium anode or an anode of a rare earth metal, which is immersed in a salt bath in the form of a salt bath consisting essentially of one of the alkali metal fluorides, of mixtures of these alkali metal fluorides and of mixtures of alkali metal fluorides with strontium fluoride or barium fluoride an addition of 0.01-40 mol # yttrium fluoride or an eluoride of the rare earths and is kept at an operating temperature of at least 500 ⁰ C, but below the melting point of the metal cathode »in an oxygen-free atmosphere} (2) Manufacture of a current flow between the anode and the cathode. * so that a current density in the range between Ö $ O1-3Ö A / dm prevails at the cathode during the formation of a coating of a yttrium compound or a metal compound of the rare earths | (3) ¥ the electrical current flow is interrupted after the desired thickness of the coating of the yttrium compound or the metal compound of one of the rare earths has formed on the iletaXlkathode * 2. Yerfahren according to claim 1, characterized in _t that the oxygen-free atmosphere is eraielt by a vacuum. 3 # It is known according to Aaspruea ^ t by the fact that the oxygen-free A1i "oephSre" is aimed by a latrtgaaatmoapiiäre "" 1O0 | 1i / 1546 4., "Method according to claims 1-3, characterized in that that the process is also carried out in a carbon. is carried out in a free atmosphere * - 5. The method according to ^ claim 1, characterized in that that a carbon anode is used and an additional one Voltage less than 3 volts is applied. 6. The method according to claim 5, characterized in that that the carbon anode is covered by a tightly woven metal mesh one of the elements KIoB, molybdenum, tantalum> Tungsten or iron is shielded. ■ '.. "..."' 7. The method according to claims 1-6, characterized in that the one consisting of a metal compound Metal bodies provided with a coating immediately after the end of the process from the molten salt bath Will get removed. 8. The method according to claims 1-7, characterized in that the operating temperature is in the range between 500-1100 ⁰ C .. 9. · Process according to claims 1-8, characterized in that, that the metal cathode consists of ITiekel. 10. The method according to claims 1-8, characterized in that the metal cathode consists of cobalt. 11. The method according to claims 1-8, characterized in that the metal cathode consists of titanium .. 12. Method according to claims 1-8, characterized in that the metal cathode consists of zirconium. 1098 18/1546