DE2442300A1 - METHOD OF ELECTROPLATING - Google Patents

Description

Patent attorney: α. Grünecker

DIPL.-INQ.

H. KINKELDEY

DR-IN3.

2442300 ^w - STOCKMAlR

DR.-INQ. · Α · Ε (CALTECH)

K. SCHUMANN

DR. RER. NAT. · OIPL.-PHYS.

P. H. JAKOB

DIPL.-INQ.

G. BEZOLD

"DR. RER. NAT. ■ DIPL.-CHEM.

MUNICH

E. K. WEIL

DR. RER. OEC. INa.

LINDAU

8 MUNICH 22

MAXIMILIANSTRASSE 43

Sept. 4, 1974-P 8492

Fuji Photo Film Co., Ltd.

No. 210, Nakanuma Minami Ashigara-Shi, Kanagawa, Japan

"Electroplating Process"

The invention relates to an electroplating process, in particular a method of electroplating in a single electroplating bath in which the plating conditions are so varied be that the deposition of a non-magnetic Plating layer and a ferromagnetic plate! Appeared be done selectively.

Of conventional memory elements that have a ferromagnetic thin layer, some elements have a ferromagnetic one Layer that is deposited on a non-magnetic substrate, and other elements have-in addition a protective, non-magnetic layer overlying the ferromagnetic layer. Representative examples. games for such storage elements are magnetic disks and

509812/1002

TELEPHONE (O8S) 222862 TELEX OB- 29 38Ο 'TELEGRAMS MONAP

Magnetic drum !! for electronic computers, audio disks for video slow motion recordings and for reproducing still images, as well as magnetic heads.

Conventional methods of making these elements include a non-magnetic layer and a ferromagnetic layer Have layer include the following stages.

In the step of forming a non-magnetic layer, a non-magnetic plating bath (e.g. a copper, Zinc, chrome or gold plating bath), and then a non-magnetic plating layer is used produced this non-magnetic plating bath. In an analogous manner, in the stage for generating a ferromagnetic Plating layer a ferromagnetic plating bath (e.g. a nickel or cobalt plating bath or a plating bath with a nickel-cobalt alloy) is used, with subsequently the formation of a ferromagnetic clad layer he follows.

However, the conventional plating methods have the following specified disadvantages.

1. To create a non-magnetic plating layer and a ferromagnetic plating layer, several plating baths are which correspond in each case to the layers to be produced are required.

2. Any process involving a non-magnetic plating step followed by a ferromagnetic plating step, or conversely, the object to be plated must be transferred from a first plating bath to a second plating bath will. Accordingly, devices for transferring are useless for this purpose of the items required, and moreover plating time losses inevitably occur.

3 · Every time plating is done in a different plating bath, there is a washing step using water

509812/1002

required to mix the plating solutions in different Avoid baths, and the entire plating process is time-consuming.

As described above, the conventional plating methods have numerous disadvantages. It is therefore an object of the invention to provide a plating method that can be done using a single plating bath in which both a non-magnetic Plating layer and a ferromagnetic plating layer are selectively deposited by changing the plating conditions can be. This object is achieved by the invention.

The invention thus relates to a method for electroplating using a single electroplating bath, which is characterized in that the electrical

Current density in the plating bath from about 0.3 to about 10 A / dm so varies that the selective deposition of a non-magnetic layer occurs when the electric current density of

about 0.3 to about 1.5 A / dm varies, and the selective deposition of a ferromagnetic layer occurs when the elek
iert

about 0.3 to about 1.5 A / dm, and the selective

ni electrical current density from approx. 0.8 to approx. 10 A / dm vari-

The plating bath used in the present invention contains salts of ferromagnetic metals such as cobalt or nickel. This plating bath has the property that the magnetic The character of a plating layer varies widely depending on the plating conditions. There are numerous plating baths in which cobalt or nickel salts are used. However, nickel salts are used more frequently, e.g. im Fall of Ni-P plating baths. The nickel ions are in the plating bath, for example, in an amount of about 1 to 300 g / liter, and the cobalt ions are present in an amount of about 1 to 300 g / liter. The amount of NaHpPO -HpO in the plating bath can e.g. vary from about 0 to 100 g / liter. '.

509812/1002

_ Zj. _

Suitable underground metals made using such Plating baths with the aforementioned properties can be plated are various non-magnetic metals, like copper, zinc or tin. However, the plating method of the invention can be applied to any metals. Suitable Plating bath compositions are exemplary below specified; however, the invention is of course not restricted to these formulations.

Cu plating baths

CuSO ₄ - ^ H ₂ O about 1. to 300 g / liter

HpSO ₄ about 5 to 30 ml / liter

A sheet copper anode, for example, is suitable as the anode.

Zn plating baths

ZnSO. about 1 to 300 g / liter

about 5 to 30 ml / liter

A sheet zinc anode, for example, is suitable as the anode. Sn plating baths

about 1 to 30 ml / liter

SnSO ^ about 1 to 300 g / liter

A tinplate anode, for example, is suitable as the anode.

When an underground metal such as copper, zinc or tin is subjected to plating using this type of plating bath is a change in the plating conditions to selectively achieve non-magnetic layers or ferromagnetic layers Layers required. The parameters in the electroplating process of the invention include the type of Electricity supply to the plating bath, the electrical current density and temperature in the plating bath, the movement (e.g. by stirring) or not moving the plating bath, the amount of stirring action, the plating time, etc. when the plating bath is kept constant.

509812/1002

_ C

By changing these parameters it is possible to have a non-magnetic layer and a ferromagnetic layer in the same Selectively deposit bath. For examinations under change This parameter was found to be the most selective in the change in electric current density in all of the plating baths Deposition of a non-magnetic layer ^ and a ferromagnetic layer allows. Generally finds at high electrical current density the deposition of a ferromagnetic layer and at low electrical current density the deposition of a non-magnetic layer takes place. However, it is difficult to change these layers or films the temperature of a plating bath selectively. In addition, the change in temperature is therefore not as effective or suitable because of the plating bath temperature necessarily has to be constantly changed. Charging the plating bath with electricity can using a pulse charging method using pulses of electrical current or a PR method which changes the polarity of the current applied to the anode and cathode.

According to the invention it was found that the change in electrical Current density during plating, and the change the type of electrical charge for changing the plating conditions for the selective deposition of a non-magnetic layer and a ferromagnetic layer are suitable.

In the plating bath according to the invention to achieve a If a ferromagnetic cladding layer and a non-magnetic cladding layer are used, the pH can be from about 2 to 6 vary. The temperature range is, for example, about 10 to 70 ° C. Nickel anode sheets with a purity of over 99.9 percent in the case of using a nickel-plating bath tin or zinc sheet anodes plated with platinum or rhodium are used in the case of a cobalt plating bath will. Suitable plating procedures are disclosed in U.S. Patents 2,644,787, 3,152,974, 3,227,635, 3,578,571, and 3,637

509812/1002

described.

To selectively deposit a non-magnetic layer and a magnetic layer in a single plating bath, it is It is important to adjust the particle size of the layer to be deposited by changing the plating conditions accordingly to steer appropriately.

The particle sizes of the deposited ferromagnetic layer range from about 500 µ to about 0.1 µ, and the particle sizes of the deposited non-magnetic layer range from about 100 µ to about 0.1 µ. These are generalizations because it is difficult to specify the range of these particle sizes because they vary somewhat depending on the composition of the plating bath.

Important factors in determining the sizes of the deposited Particles are the composition of the plating bath and the electrical current density during plating. According to the Composition of the plating bath is the electric current density in the creation of a non-magnetic layer and a ferromagnetic layer varies by plating. In this case, the deposition takes place at a low electrical current density a non-magnetic layer and, if the electrical current density is high, the deposition of a ferromagnetic one Layer.

In this case, the electric current density is about 0.3 to

10 A / dm. In detail, the current density is during the deposition a non-magnetic layer about 0.3 to 1.5 A / dm, and for the deposition of a ferromagnetic layer about

2 2

0.8 to 10 A / dm, preferably 0.8 to 4 A / dm. Here too. these are only indicative, as it is difficult to determine the range of the electrical current density in the individual, because the duty according to the composition the plating bath and the sizes of those to be deposited Particle varies to some extent.

509812/1002

An example of a nickel plating bath suitable according to the invention is given below. -

NiSO ^ -6H ₂ O 0.1 until 10 10 until 30th G NiCl ₂ -OH ₂ O 10 until 40 ° 5 until 6th H ₃ BO ₃ until. 20th G NaH ₂ PO ₂ -2H ₂ O 0.1 • until 20th G pure water 1 liter Current density: A / dm 2 Temperature: G

Determining whether the cladding layer is a non-magnetic Layer or a ferromagnetic layer represents, takes place according to the occurrence of a saturation magnetization (Bm) in the hysteresis curve obtained with a B-H measuring device will. The test sample of the

ο
Platinum layer is 1 cm in size and 0.05 to 0.1 μ thick.

Various types of plating can be used for plating. Electrodes ,. eg a nickel electrode, a. Sheet copper anode, a sheet zinc anode, a platinum or rhodium plated (about 0.1 to 0.5 η thickness) copper or sheet tin anode can be used. A nickel electrode is particularly preferred when the plating bath is a nickel system.

From the foregoing it follows that the method of the invention is completely free from the disadvantages of conventional plating processes. In particular, conventional plating processes require inevitably a large number of plating baths to produce a non-mangetic layer and a ferromagnetic layer Layer, and all of the disadvantages of conventional methods, stem from the need for multiple plating baths here. With the method of the invention, however, it is possible to selectively use both a non-magnetic layer and a ferromagnetic layer using a single plating bath as described in detail above

509812/1002;

is. Thus, the method of the invention overcomes all of the disadvantages of conventional methods.

The examples illustrate the invention. For the expert it is obvious that the components, their _{relationships>} and the order may be changed to the stage, where appropriate, to the extent these changes do not exceed the scope of the invention. Unless stated otherwise, all parts, percentages, proportions and other data in the examples are based on weight.

example 1

A plating bath of the recipe given in Table I is used, which is equipped with a sheet nickel anode (nickel purity 99} 9 percent) and a copper sheet carrier material (copper purity 99j9 percent), which was previously equipped with a B-H measuring device as has been identified non-magnetically. The plating of the copper sheet is done by changing the electrical Current density during plating.

Tabel Recipe I. 300 g 5 ° C NiSO ^ 7H ₂ O 50 g 0.4 NiCl ₂ -OH ₂ O 40 g ^H 3 ^BO 3 Λ / j, gr NaH ₂ PO ₂ -2H ₂ O 1000 ml pure water Bath conditions 45 ± Plating bath temperature 4 _y 6 ± pH

The plating conditions and results are shown in Table II.

509812/1002

Table II

Sample ITr. __

Plating electrical
cond- current density
gings: (A / dm ^) 0.5 1.2, 1.5 2 3 3.2

Plating time (see) 60 40 40 40 40 25

magnetic properties χ χ ο ο ο ο Coercive force: Hc (Oe) - 5 4-0 80 74- ■

Square ratio:

SQ (Br / Bs) - - 0.82 0.78 0.67 0.80

ο = ferromagnetic
χ = non-magnetic

In Table II and in Tables IV, VI, ¹ VIII and X the symbols used have the following meanings: ο = ferromagnetic properties χ = non-magnetic properties

From the results shown in Table II, it can be seen that in the plating bath used, an electrical Current density of 1.5 A / dm or more, a ferromagnetic clad layer, and at an electric current density of 1.2 A / dm or less, a non-magnetic plating layer is deposited.

The value for the saturation magnetization of the obtained ferromagnetic Plating layer is 5800 Gs / ml. It is an excellent nickel plating layer with a Saturation magnetization, which roughly corresponds to that of ITiekel. -

509812/1002

Example 2

A plating bath of the recipe given in Table III is used used with a sheet nickel anode (nickel purity 99.9 percent) and a zinc sheet carrier material (zinc purity 99.8 percent), which was previously equipped with a B-H measuring device has been identified as non-magnetic. The plating is carried out with a change in the electric current density and the plating time.

Table III Recipe 23O g NiSO ₄ .7H ₂ O 45 p 40 g H ₃ BO ₃ 4 g NaH ₂ PO ₂ -2H ₂ O 1000 ml pure water Bath conditions 50 ± 4 ⁰ C Plating bath temperature 4.8 i 0.4 pH

The plating conditions and results are shown in Table IV.

Tabel electrical
Current density
(A / dm ² ) 7th IV 8th sample 10 11 12th Plating
time (see) 0.4 0.5 9 0.8 1.2 5.0 properties 60 60 0.6 90 90 40 Plating
conditional
made: Coercive Force: Hc (Oe) X X 60 O O O X 60 124 84 magnetic

Square ratio:

SQ (Br / Bs) - - - 0.82 0.78 0.87

509812/1002

It can be seen from the results in Table IV that the plating bath used had non-magnetic plating layers and ferromagnetic clad layers are obtained when the electrical current density 0.6 A / dm or less .bzw.

Is 0.8 A / dm or more.

Example 3 '

Using a plating bath according to the recipe given in Table V, a copper carrier material is obtained in the same way Manner as described in Examples 1 and 2, plated. The plating conditions and results are in Table VI compiled.

Table V Recipe Tabel 100 g VI sample 16 ■ 17th Ni (BF ^) ₂ 15 g 14 15 2.0 2.5 ^H ₃ ^BO ₃ 15th 4 g .-- 1.4 1.7 60 60 NaH ₂ PO ₂ • 2H ₂ O Plating electrical
cond- current density
gung; (A / dm) 1.0 1000 ml 60 40 O O pure water Plating
time (see) 60 X O. 80 110 Bath conditions magnetic properties χ 25 ± 5 ° C 30th 0.76 0.72 Plating bath temperature Coercive force: Hc (Oe) - 3.5 0.88 pH Square ratio:
SQ (Br / Bs)

50981 2/1002

Table VI shows that using the indicated plating bath a non-magnetic clad layer is formed when the electric current density is 1.4 A / dm or less, and a ferromagnetic clad layer is formed when the density is 1.7 A / dm or more.

Example 4

Using a plating bath according to the recipe given in Table VII, a copper substrate is made in the same way Manner as described in Examples 1 to 3, plated. The plating conditions and the results are in Table VIII compiled.

Tabel Ee recipe Tabel Plating electrical VII 140 S. 21 - 22nd NiSO.-7H ₀ O cond- current density 40 ε 18th steps: (A / dm) 0.8 80 G NH ₄ Cl Plating 8th ε 2.0 2.5 NaH ₂ PO ₂ -2H ₂ O time (see) 60 1000 ml pure water magnetic properties χ 40 50 Bath conditions Coercive Force: Hc (Oe) 45 ± 5 ° ( 1
J O O Plating bath temperature Square ratio 5.5 43 48 pH SQ (Br / Bs). sample 0.72 0.71 VIII 20th 19th 2 1.5 1, . 40 O 40 21 χ ■ - 0.88 -

509812/1002

Table VIII shows that using the indicated plating bath a ferromagnetic clad layer is obtained,

when the electric current density is 1.5 A / dm or more, and a non-magnetic clad layer is obtained when

the density is 1.2 A / dm or less.

Example 5

Using a plating bath according to the method shown in Table IX given recipe is a copper carrier material in the same Manner as described in Examples 1 to 3, plated. The plating conditions and results are in Table X. compiled.

Table IX Recipe

CoSO ₄ -7H ₂ O Table X 10 G , 5 2Pr ■ CoCl ₂ -6H ₂ O "5 S. Ξ, ΒΟ 30th S. 1.5 NaH ₂ PO ₂ - H ₂ O Plating condition- electrical current- 4-0 S. 10 pure water gings: density (A / dm) 1000 ml ■ O Bath conditions Plating time (see) 280 Plating bath temperature magnetic properties ³ C 0.71 pH Coercive Force: Hc (Oe) 5.5 ± 0 Square ratio SQ (Br / Bs) sample 23 0.5 30th X - _

5098 12/1002

Table X shows that when the specified plating bath is used, a ferromagnetic plating layer is obtained when the electric current density is 1.5 A / dm, and a non-magnetic plating layer is obtained when the current density is 0.5 A / dn ² .

From the results of the preceding examples in which various Types of plating baths and carrier metals used can be seen in each case by change the plating conditions selectively both a non-magnetic plating layer and a ferromagnetic plating layer can be obtained.

When examining the hardness and surface roughness of the clad layers obtained, no unusual deviations are found found; the clad layers obtained have excellent brilliance.

Claims

509 8 12/1002

Claims (12)

Patent to s ρ r ü c h e 1. Method of electroplating using a single Elektroplattxerbad, characterized in that the electrical current density in Plating bath varied from about 0.3 to about 10 A / dm so that the selective deposition of a non-magnetic layer occurs when the electric current density is about 0.3 to about 2 ' 1.5 A / dm, and the selective deposition of a ferromagnetic Layer occurs when the electrical current density ο
is about 0.8 to about 10 A / dm. 2. The method according to claim 1, characterized in that cladding layers are produced, the particles having a size from about 100 S to about 0.1 u. · . · / 3 · method according to at least one of claims 1 and 2, characterized in that non-magnetic plating layers produced containing particles from about 100 microns to about 0.1 microns in size. 4. The method according to at least one of claims 1 to 3 »characterized in that ferromagnetic cladding layers are produced which contain particles with a size of about 500 S. to about 0.1 ρ. , ■ '■' 5 method according to at least one of claims 1 to 4, characterized in that an electroplating bath is used which has at least one copper, zinc, chromium, gold, tin, Contains phosphorus, nickel and / or cobalt compound. 6. The method according to at least one of claims 1 to 5 » characterized in that - that an electroplating bath is used, which contains at least one copper, zinc, chromium, gold, phosphorus and / or tin compound. 5,098 12/100 2 7 · method according to at least one of claims 1 to 6, characterized in that an electroplating bath is used which has at least one nickel, cobalt, chromium and / or Contains phosphorus compound. 8. The method according to at least one of claims 1 to 7 » characterized in that an electroplating bath is used which contains nickel and / or cobalt as main components. 9- method according to at least one of claims 1 to 8, ^ characterized in that an electroplating bath is used which has at least one copper, zinc, chromium, gold, tin and / or contains phosphorus compound as an additional component. 10. The method according to at least one of claims 1 to 9 » characterized in that one has a non-magnetic layer produced, which mainly contains nickel and / or cobalt as components. 11. The method according to at least one of claims 1 to 10, characterized in that a non-magnetic layer is produced which contains copper, zinc, chromium, gold ₁ tin and / or phosphorus as an additional component. 12. The method according to at least one of claims 1 to 11, characterized in that a magnetic layer is produced, which mainly contains nickel and / or cobalt as components. 13- method according to at least one of claims 1 to 12, characterized in that a magnetic layer is produced which has chromium and / or phosphorus as an additional component contains. 50981 2/1002