U.S. patent application number 15/290058 was filed with the patent office on 2017-02-02 for process to deposit zinc-iron alloy layer material.
This patent application is currently assigned to Atotech Deutschland GmbH. The applicant listed for this patent is Atotech Deutschland GmbH. Invention is credited to Lukas BEDRNIK, Frantisek HAAS, Nadine LANG, Roland VOGEL.
Application Number | 20170029971 15/290058 |
Document ID | / |
Family ID | 43983758 |
Filed Date | 2017-02-02 |
United States Patent
Application |
20170029971 |
Kind Code |
A1 |
BEDRNIK; Lukas ; et
al. |
February 2, 2017 |
Process to deposit zinc-iron alloy layer material
Abstract
A process for depositing a zinc-iron alloy layer material having
a body centred cubic crystal structure of the .GAMMA.-phase, a
(330) texture and an iron content of 12 to 20 wt.-% including the
steps (i) providing a metallic substrate, (ii) contacting the
substrate with an alkaline aqueous zinc-iron alloy plating bath
containing 4 to 6 g/l zinc ions, 1 to 3 g/l iron ions, 25 to 35 g/l
hydroxyl ions, 0.5 to 2.5 g/l of a quaternary ammonium polymer and
at least one complexing agent selected from the group consisting of
hydroxyl carboxylic acids and salts thereof and simultaneously
applying a current to the substrate. The zinc alloy layer material
provides a high corrosion protection to metallic substrates, has a
high hardness and a bright appearance.
Inventors: |
BEDRNIK; Lukas; (Tanvald,
CZ) ; HAAS; Frantisek; (Jablonec nad Nisou, CZ)
; LANG; Nadine; (Berlin, DE) ; VOGEL; Roland;
(Berlin, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Atotech Deutschland GmbH |
Berlin |
|
DE |
|
|
Assignee: |
Atotech Deutschland GmbH
Berlin
DE
|
Family ID: |
43983758 |
Appl. No.: |
15/290058 |
Filed: |
October 11, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13985294 |
Aug 14, 2013 |
|
|
|
PCT/EP2012/051468 |
Jan 30, 2012 |
|
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15290058 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25D 3/565 20130101;
Y10T 428/12792 20150115; B32B 15/013 20130101; C25D 5/48
20130101 |
International
Class: |
C25D 3/56 20060101
C25D003/56 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2011 |
EP |
11154475.5 |
Claims
1. A process for depositing a zinc-iron alloy layer material having
a body centred cubic crystal structure of the .GAMMA.-phase, a
(330) texture and an iron content of 12 to 20 wt.-% comprising the
steps (i) providing a metallic substrate, (ii) contacting the
substrate with an alkaline aqueous zinc-iron alloy plating bath
comprising 4 to 6 g/l zinc ions 1 to 3 g/l iron ions 25 to 35 g/l
hydroxyl ions, 0.5 to 2.5 g/l of a quaternary ammonium polymer and
at least one complexing agent selected from the group consisting of
hydroxyl carboxylic acids and salts thereof and simultaneously
applying a current to the substrate.
2. The process according to claim 1 wherein the quaternary ammonium
polymer is an ureylene quaternary ammonium polymer according to
formula (1): ##STR00002## wherein m is 2 or 3, n is at least 2, R1,
R2, R3 and R4 are the same and are selected from methyl, ethyl and
hydroxyethyl, p ranges from 3 to 12 and X- is selected from Cl-,
Br- and I-.
3. The process according to 1 the alkaline aqueous zinc-iron alloy
plating bath further comprises an alkanolamine compound.
4. The process according to 2 the alkaline aqueous zinc-iron alloy
plating bath further comprises an alkanolamine compound.
5. The process according to claim 3 wherein the alkanolamine
compound is selected from monoethanolamine, diethanolamine,
triethanolamine, propanolamine, N-methylethanolamine and
N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylenediamine.
6. The process according to claim 4 wherein the alkanolamine
compound is selected from monoethanolamine, diethanolamine,
triethanolamine, propanolamine, N-methylethanolamine and
N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylenediamine.
7. The process according to claim 3 wherein the concentration of
the alkanolamine compound ranges from 8 to 20 g/l.
8. The process according to claim 4 wherein the concentration of
the alkanolamine compound ranges from 8 to 20 g/l.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a U.S. divisional application
which claims benefit of and priority under 35 U.S.C.
.sctn..sctn.120 and 121 to co-pending U.S. National Stage
application Ser. No. 13/985,294, which was filed on 14 Aug. 2013,
now ______, which is based on and claims benefit and priority under
35 U.S.C. .sctn.371 of International Application No.
PCT/EP2012/051468, filed 30 Jan. 2012, which in turn claims benefit
of and priority to European Application No. EP 11154475.5, filed 15
Feb. 2011, the entirety of each of which is hereby incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a hard zinc-iron alloy layer
material having a bright appearance and which is useful to provide
corrosion protection to a metallic substrate.
BACKGROUND OF THE INVENTION
[0003] Zinc-nickel alloys are well known as corrosion protection
layers for metallic substrates. Such alloys are deposited from
alkaline plating baths by electroplating. Typical plating bath
compositions are disclosed for example in U.S. Pat. No. 5,405,523,
U.S. Pat. No. 5,435,898, U.S. Pat. No. 6,652,728 B1 and U.S. Pat.
No. 6,706,167 B1. The nickel content in zinc-nickel alloy layers
deposited from such plating bath compositions ranges from 12 to 16
wt.-%. Zinc-nickel alloy layers provide a sufficient corrosion
protection to metallic substrates such as iron based alloys and at
the same time have a bright appearance and a Vickers hardness of
>500 HV0.0025.
[0004] Due to the toxicity of nickel ions released in small
quantities from such zinc-nickel alloy layers alternative zinc
alloy layers with lower toxicity but similar properties in terms of
corrosion protection, bright appearance and sufficient hardness are
needed.
[0005] Plating bath compositions as those disclosed in U.S. Pat.
No. 5,405,523, U.S. Pat. No. 5,435,898, U.S. Pat. No. 6,652,728 B1
and U.S. Pat. No. 6,706,167 B1 can be used to deposit zinc-iron
alloys as well. However, zinc-iron alloys deposited from such
plating bath compositions have an iron content of .ltoreq.1 wt.-%
iron and do not fulfil the requirements in terms of corrosion
protection and hardness of the alloy layer. Zinc-iron alloys having
a higher iron content deposited from such plating bath compositions
show an inhomogeneous iron distribution in the deposited layers and
therefore provide no sufficient corrosion protection to the
underlying substrate.
[0006] In case of a higher iron ion concentration in such zinc-iron
alloy plating bath compositions a mixture of various intermetallic
zinc-iron phases is deposited. Furthermore, a non-uniform grain
structure is obtained. This leads to a poor reproducibility of
deposit properties such as corrosion protection properties,
hardness and appearance.
[0007] An alkaline process for deposition of zinc-iron alloy layers
having an iron content of 15-25 wt.-% is described by V.
Narasimhamurthy, B. S. Sheshadri, Metal Finishing (1997) 44.
However, the process suffers from a steep increase of iron content
in the coating at current densities lower than 1 A/dm.sup.2. Hence,
such a plating bath is unsuitable for plating of substrates having
a complex shape.
[0008] A plating bath for deposition of zinc-iron alloy layers
having an iron content of 17-20 wt.-% is disclosed in CN 101545125
A. A zinc-iron alloy layer material deposited from such a plating
bath and successively coated with a Cr.sup.3+ ion containing
passivation layer provides a corrosion protection which is not
sufficient for most applications. Formation of 5% white rust in a
neutral salt spray test was already observed after 65 h in case of
a zinc-iron layer material containing 17.5 wt.-% iron. Furthermore,
use of up to 1 g/l EDTA in the process is a severe limitation for
industrial application.
Objective of the Present Invention
[0009] It is therefore the objective of the present invention to
provide a zinc-iron alloy layer material having a high homogeneity
in terms of alloy composition, corrosion protection properties,
hardness and bright appearance.
[0010] Another object of the present invention is to provide an
alkaline aqueous plating bath suitable for deposition of a
zinc-iron alloy layer material with a high homogeneity in terms of
alloy composition, corrosion protection properties, hardness and
bright appearance.
[0011] Still another object of the present invention is to provide
a process for deposition of zinc-iron alloy layer material with a
high homogeneity in terms of alloy composition, corrosion
protection properties, hardness and bright appearance.
SUMMARY OF THE INVENTION
[0012] The first objective is solved by a zinc-iron alloy layer
material having a body centred cubic crystal structure of the
.GAMMA.-phase with a (330) texture and an iron content in the range
of 12 to 20 wt.-%.
[0013] The second objective is solved by an alkaline aqueous
zinc-iron alloy plating bath comprising [0014] 4 to 6 g/l zinc ions
[0015] 1 to 3 g/l iron ions [0016] 25 to 35 g/l hydroxyl ions,
[0017] 0.5 to 2.5 g/l of a quaternary ammonium polymer and [0018]
at least one complexing agent selected from the group consisting of
hydroxyl carboxylic acid salts.
[0019] The third objective is solved by a process for depositing a
zinc-iron alloy layer material having a body centred cubic crystal
structure of the .GAMMA.-phase with a (330) texture and an iron
content in the range of 12 to 20 wt.-% comprising the steps [0020]
(i) providing a metallic substrate and [0021] (ii) contacting the
substrate with said alkaline aqueous plating bath and
simultaneously applying a current to the substrate.
[0022] Formation of less than 1% white rust in a neutral salt spray
test according to ISO 9227 NSS of a steel substrate coated with a
zinc-iron alloy layer material according to the present invention
and a passivation layer containing Cr.sup.3+ ions is only observed
after 672 h.
[0023] The zinc-iron alloy layer material has a bright appearance
and a Vickers hardness exceeding 380 HV0.0025.
BRIEF DESCRIPTION OF THE FIGURES
[0024] FIG. 1 shows the position and height of the .GAMMA.-ZnFe
alloy phase (330) reflection (Cu k alpha) as a function of the iron
content in the deposited layer.
[0025] FIG. 2 shows the results from X-ray diffraction measurements
(Cu k alpha) of a zinc-iron alloy layer having an iron content of
15.5 wt.-% deposited by the process according to the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The zinc-iron alloy layer material shows a narrow range of
12 to 20 wt.-% iron. The average concentration of iron is 16 wt.-%.
The observed concentration of iron and further evidence by X-ray
diffraction measurements of zinc-iron alloy layers having an iron
content in the range of 12 to 20 wt.-% show that an exclusive
presence of the body centred cubic .GAMMA.-ZnFe alloy phase is
obtained by the process according to the present invention. FIG. 1
shows the peak position of the (330) reflection of the .GAMMA.-ZnFe
alloy phase as determined by X-ray diffraction measurements using
Cu k alpha radiation. The average (330) reflection position is
42.8.degree. (Cu k alpha).
[0027] Surprisingly, the zinc-iron alloy layer material according
to the present invention has a strong crystallographic (330)
texture which is reflected by the exclusive occurrence of the (330)
reflection of the .GAMMA.-ZnFe alloy phase determined by X-ray
diffraction measurements (FIG. 2). All other reflections observed
belong to the underlying copper substrate coated for the
measurement.
[0028] The term "texture" as used herein carries the meaning that
would be understood by those of skill in the crystallographic arts.
The crystallographic texture is caused by a preferred orientation
of individual crystallites in the polycrystalline zinc-iron layer
material according to the present invention.
[0029] The (330) plane has the highest density of atoms in the body
centred cubic crystal structure of the .GAMMA.-ZnFe alloy phase.
Said strong crystallographic (330) texture is observed within the
whole current density range of 0.01 to 10 A/dm.sup.2 which means on
all areas of a substrate having a complex shape. Accordingly, the
zinc-iron alloy layer material shows very homogeneous corrosion
protection properties for an underlying substrate, a high hardness
and a bright appearance.
[0030] The body centred cubic crystal structure of the
.GAMMA.-phase with a (330) texture and an iron content in the range
of 12 to 20 wt.-% is obtained in a current density range from 0.01
to 10 A/dm.sup.2.
[0031] Hence, the homogeneous properties are also achieved in case
of substrates having a complex shape, such as fasteners, fixing
elements, door hinges, lock casings, and the like.
[0032] Up to date, the .GAMMA.-ZnFe alloy phase can only be
obtained in form of a bulk material without the beneficial
crystallographic (330) texture by powder metallurgical preparation
methods.
[0033] The zinc-iron alloy layer material according to the present
invention is not only obtained by a wet chemical deposition method
but also reveals a strong crystallographic (330) texture and is,
accordingly to XRD measurements (Example 3), obtained in a pure
form, i.e. the .GAMMA.-ZnFe alloy phase.
[0034] The different crystallographic structure of the zinc-iron
alloy layer material according to the present invention compared to
zinc-iron alloy layer materials known in the art is furthermore
demonstrated by enhanced corrosion protection properties. It is
assumed by the inventors, that zinc-iron alloy layer materials
having an iron content in the range of 17-20 wt.-% as disclosed in
CN 101545125 A are a mixture of different zinc-iron alloy
phases.
[0035] Typical metallic substrate materials are steel and other
ferrous base metals.
[0036] Formation of less than 1% white rust in a neutral salt spray
test according to ISO 9227 NSS of a steel substrate coated with a
zinc-iron alloy layer material according to the present invention
and a passivation layer containing Cr.sup.3+ ions is only observed
after 600 to 1000 h.
[0037] The zinc-iron alloy layer material has a bright appearance
and a Vickers hardness exceeding 380 HV0.001.
[0038] The zinc-iron alloy layer material having a body centred
cubic crystal structure of the .GAMMA.-phase with a (330) texture
and an iron content in the range of 12 to 20 wt.-% is obtainable by
a process comprising the steps of [0039] (i) providing a metallic
substrate, [0040] (ii) contacting the substrate with said alkaline
aqueous plating bath comprising [0041] 4 to 6 g/l zinc ions [0042]
1 to 3 g/l iron ions [0043] 25 to 35 g/l hydroxyl ions, [0044] 0.5
to 2.5 g/l of a quaternary ammonium polymer and [0045] at least one
complexing agent selected from the group consisting of hydroxyl
carboxylic acid salts and simultaneously applying a current to the
substrate.
[0046] The aqueous plating bath comprises zinc ions in a
concentration of 4 to 6 g/l. Suitable sources for the zinc ions are
water soluble zinc salts, zinc oxide and zinc metal. The water
soluble zinc salts are selected from the group comprising zinc
sulphate, zinc chloride, zinc nitrate, zinc gluconate and zinc
citrate.
[0047] The preferred sources of zinc ions are ZnO and zinc
metal.
[0048] The Zn content is generally maintained during use of the
alkaline plating bath by dissolution of Zn metal.
[0049] The concentration of iron ions in the aqueous plating bath
ranges from 1 to 3 g/l, more preferably from 1.5 g/l to 2.5 g/l.
Suitable sources for iron ions are water soluble salts of iron,
such as ferrous sulphate, ferric sulphate and ferric chloride. The
oxidation state of iron in the source material of the iron ions is
not important as long as the source of iron ions is soluble in the
alkaline plating bath.
[0050] The aqueous plating bath contains 25 to 35 g/l hydroxyl ions
which can be added as NaOH, KOH and NH.sub.4OH.
[0051] The aqueous plating bath further contains a quaternary
ammonium polymer in a concentration of 0.5 to 5 g/l, more
preferably from 1 g/l to 2 g/l.
[0052] Preferably, the quaternary ammonium polymer is an ureylene
quaternary ammonium polymer.
[0053] More preferably, the quaternary ammonium polymer is selected
from polymers according formula (1)
##STR00001##
wherein m is 2 or 3, n is at least 2, R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are the same and are selected from methyl, ethyl and
hydroxyethyl, p ranges from 3 to 12 and X.sup.- is selected from
Cl.sup.-, Br.sup.- and I.sup.-.
[0054] The aqueous plating bath contains at least one complexing
agent which is selected from hydroxyl carboxylic acid salts with
sodium and potassium. The concentration of the at least one
hydroxyl carboxylic acid salt ranges from 5 to 15 g/l, more
preferably from 7 g/l to 12 g/l. Suitable complexing agents are
selected from the group comprising citrates, tartrates, gluconates,
glucoheptonates and glycollates of sodium and potassium.
[0055] Optionally the aqueous zinc-iron plating bath further
comprises at least one alkanolamine compound. The concentration of
the at least one optional alkanolamine compound ranges from 5 to 20
g/l, more preferably 8 g/l to 12 g/l. The at least one optional
alkanolamine compound is selected from the group comprising
monoethanolamine, diethanolamine, triethanolamine, propanolamine,
N-methylethanolamine and
N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylenediamine.
[0056] The aqueous plating bath according to the present invention
is free of strong complexing agents such as ethylenediamine
tetraacetic acid, (nitrilo-triacetic acid, diethyl triamine
penta-acetic acid, 1,3-propylene diamine penta-acetic acid and
salts thereof.
[0057] The process for depositing a zinc-iron alloy having an iron
content of 12 to 20 wt.-% comprises the steps [0058] (i) providing
a metallic substrate, [0059] (ii) contacting the substrate with
said alkaline aqueous plating bath comprising and simultaneously
applying a current to the substrate.
[0060] The substrate to be plated is cleaned by a typical
pretreatment cycle for ferrous base materials, i.e. soak cleaning,
electrocleaning, pickling and rinsing.
[0061] The substrate to be coated with the zinc-iron alloy layer
material having an iron content of 12 to 20 wt.-% is contacted with
the aqueous plating bath described above. A direct current is
passed from an anode to the cathodic substrate during deposition.
The current density applied ranges from 0.01 to 10 A/dm.sup.2, more
preferably from 1 to 3 A/dm.sup.2. The aqueous plating bath is held
at a temperature in the range of 15 to 45.degree. C., more
preferably 20 to 30.degree. C., during deposition.
[0062] In a preferred embodiment of the present invention the
zinc-iron alloy layer material is coated with a passivation layer.
Such a passivation increases the corrosion protection for the
underlying substrate material. Preferred passivation layers
comprise Cr.sup.3+ ions which can be deposited from aqueous
composition containing 2 to 10 g/l of Cr.sup.3+ ions, 2 to 20 g/l
of nitrate, 0.5 to 2 g/l of fluoride and optionally 5 to 10 g/l of
acid soluble colloidal silica and/or 0.2 g/l Co.sup.2+ ions. The
passivation solution is kept in a pH range of 1.5 to 4.0 at 20 to
60.degree. C.
[0063] In another embodiment of the present invention the
passivation layer is coated with a sealing layer which even further
enhances the corrosion protection of the underlying substrate
and/or serves as a adhesion promoter for a paint.
EXAMPLES
[0064] The invention will now be illustrated by reference to the
following non-limiting examples.
Plating Procedure:
[0065] Steel sheets having a size of 70.times.70.times.1 mm.sup.3
were immersed in soak cleaner Uniclean 155 at 70.degree. C. for 30
min, rinsed, pickled in 15% hydrochloric acid for 30 s, rinsed,
electrolytically cleaned in Nonacid 701 electrocleaner at
22.degree. C. for 30 s under cathodic and 30 s anodic polarization
at current density of 2 A/dm.sup.2, and finally rinsed in a 3 stage
cascade rinse. Next, a zinc-iron alloy layer was deposited from a
plating baths discussed in the respective examples.
[0066] The substrates were rinsed with water and then a passivation
layer containing Cr.sup.3+ ions was deposited onto the zinc-iron
alloy layer from a passivation bath EcoTri.RTM. HC2 or Tridur.RTM.
Ultra (products of Atotech Deutschland GmbH).
[0067] The steel sheets were rinsed again with water and dried.
Test Methods:
[0068] For determination of alloy composition, separate samples
made from Cu substrate were coated under same conditions as
respective steel test samples. The alloy composition was measured
on the Cu substrates with XRF spectrometry.
[0069] Neutral salt spray tests were performed according to ISO
9227 NSS and evaluated according to ISO 3000258. The results are
given with the respective examples.
[0070] The hardness of zinc-iron alloy layer was determined with a
Fischerscope H100C by instrumented indentation test according to
ISO 14577. The applied stencil force was 10 to 50 mN. Vickers
hardness was calculated from the measured indentation hardness HIT
according to the theoretical equation HV=0.0945 HIT.
[0071] Optical appearance was determined by optical inspection of
the coated steel sheets. The desired appearance is denoted "bright"
whereas "technically bright" means less bright than "bright".
X-Ray Diffraction (XRD) Measurements:
[0072] A Bruker D8 Discover diffractometer was used for all
measurements in Examples 3 and 4. The XRD settings were the
following: [0073] anode: copper-.lamda.=1.5406 .ANG.; [0074]
detector: Vantec-1 (Position Sensitive Detector, PSD) [0075]
divergence slits: Goebel mirror (parallel beam)-0.6 mm slit+soller
slit [0076] PSD angle: 3.degree. [0077] receiving slit width: 14 mm
[0078] anti-scattering slit width: 10 mm [0079] theta/theta
configuration--locked coupled 2 theta scan from 30.degree. to
150.degree. with a 0.04.degree. step and 1 s.
Comparative Example 1
[0080] A zinc-iron alloy layer was deposited onto a steel sheet
from a plating bath composition disclosed in Example 17 in U.S.
Pat. No. 6,652,728 B1.
[0081] The iron content of the zinc-iron alloy is 0.6 wt.-%.
[0082] Formation of white rust was observed after 240 h salt spray
test.
[0083] The hardness of the layer ranges from 150 to 220
HV0.0025.
[0084] The layer has a technically bright appearance.
Comparative Example 2
[0085] A zinc-iron alloy layer was deposited onto a steel sheet
from a plating bath comprising 7 g/l zinc ions, 1.5 g/l iron ions,
70 g/l NaOH, 25 ml/l of complexing agent and 1.2 g/l of a polymer
according to formula (1) wherein R1, R2, R3 and R4 are methyl, m=3
and p=4.
[0086] The iron content of the zinc-iron alloy is 9 wt.-%.
[0087] The hardness of the layer is 300 HV0.001.
[0088] The characteristic (330) reflection of the .GAMMA.-ZnFe
phase at 2.THETA.=42.8.degree. was not observed in the X-ray
diffraction pattern (FIG. 1).
[0089] Formation of 1% white rust was observed after 312 h salt
spray test.
[0090] The layer has a bright appearance.
Comparative Example 3
[0091] A zinc-iron alloy layer was deposited onto a steel sheet
from a plating bath comprising 6 g/l zinc ions, 4 g/l iron ions, 70
g/l NaOH, 25 ml/l of complexing agent and 1.2 g/l of a polymer
according to formula (1) wherein R1, R2, R3 and R4 are methyl, m=3
and p=4.
[0092] The iron content of the zinc-iron alloy is 21 wt.-%.
[0093] The hardness of the layer is 450 HV0.001.
[0094] A steep decrease of the relative intensity of the
characteristic (330) reflection characteristic for the .GAMMA.-ZnFe
phase at 2.THETA.=42.8.degree. was observed (FIG. 1). New
reflections in the X-ray diffraction pattern at
2.THETA.=35.degree., 73.2.degree. and 128.degree. were observed
indicating a different crystallographic phase of the resulting
zinc-iron alloy layer.
[0095] Formation of 1% white rust was observed after 480 h salt
spray test.
[0096] The layer has a bright appearance.
Example 1
[0097] A zinc-iron alloy layer was deposited onto a steel sheet
from a plating bath comprising 6 g/l zinc ions, 2 g/l iron ions, 70
g/l NaOH, 25 ml/l of complexing agent, 1.2 g/l of a polymer
according to formula (1) wherein R1, R2, R3 and R4 are methyl, m=3
and p=4.
[0098] The iron content of the zinc-iron alloy is 16 wt.-%
[0099] The hardness of the layer is 440 HV0.001.
[0100] Formation of 1% white rust was observed after 672 h salt
spray test.
[0101] The layer has a bright appearance.
Example 2
[0102] Different zinc-iron alloy layer materials having an iron
content in the range of 8 to 24 wt.-% were deposited onto sample
holders made of copper.
[0103] The as deposited zinc-iron alloy layers deposited onto
copper sample holders were investigated by means of X-ray
diffraction (XRD) measurements.
[0104] The occurrence of the (330) reflection of the .GAMMA.-ZnFe
phase at 2.THETA.=42.8.degree. was investigated in respect to the
iron content in the deposit by determining the position of said
reflection and the relative intensity of said reflection. The data
are summarized in FIG. 1.
[0105] The (330) reflection of the .GAMMA.-ZnFe phase is observed
in the range of 12 to 20 wt.-% iron in the deposit. A maximum
height of the (330) reflection was observed for a deposit having an
iron content of approx. 18 wt.-%.
Example 3
[0106] A zinc-iron alloy layer material having an iron content of
15.5 wt.-% was deposited onto a sample holder made of copper and
subjected to a X-ray diffraction measurement.
[0107] The X-ray diffraction pattern of the zinc-iron alloy layer
material having an iron content of 15.5 wt.-% is shown in FIG. 2
together with lines representing calculated reflection positions
and relative intensities of the reflections for a .GAMMA.-ZnFe
phase (data used for calculation taken from De Wit et al., J.
Mater. Engineering and Performance, 8 (1999), 531). Reflections of
the sample holder made of copper are also present in the
diffraction pattern.
[0108] FIG. 2 shows that the layered material of the .GAMMA.-ZnFe
phase having an iron content of 15.5 wt.-% which was obtained by a
process according to the present invention has a (330) texture.
* * * * *