JPH02301591A - Iron-nickel alloy plating bath - Google Patents

Abstract

PURPOSE:To facilitate the control of physical properties and to prolong the service life of a plating soln. by adding malate and citrate as complexing agents to an aq. soln. contg. Ni and Fe ions, a pH buffer, a pH adjusting agent and a surfactant. CONSTITUTION:Malate and citrate as complexing agents for Ni and Fe ions are simultaneously added to an aq. soln. contg. Ni and Fe ions, a pH buffer and a pH adjusting agent for these ions and a surfactant. The pref. concn. of the malate is about 0.10-1.0mol/l and that of the citrate is about 0.10-0.8mol/l. When the resulting Fe-Ni alloy plating bath is used, a high quality plating film having stable magnetic characteristics over a long period of time is obtd. This method may be applied to stabilize a plating bath for forming a plating film of 'Permalloy(R)' used for magnetic recording.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to bath stabilization of permalloy plating solutions used in magnetic recording.

[Prior Art] High-performance soft magnetic materials have been used for magnetic recording thin film heads, perpendicular magnetic recording media, and the like.

Commonly used soft magnetic materials include permalloy films made by electroplating, permalloy films made by sputtering, sendust films, amorphous Co-Zr alloys, and permalloy films made by vapor deposition. It is used.

Its characteristics include low internal stress, high saturation magnetic flux density, low coercive force, low anisotropic magnetic field, and close to ideal hysteresis curve.

The plating method is often selected when a certain level of film thickness of the soft material is required or when mass production is required.

[Problem to be Solved by the Invention 1] However, the iron-nickel alloy plating bath of the prior art lacks bath stability of the plating solution itself, and has many problems such as precipitation and deterioration of magnetic properties.

Therefore, the present invention C is intended to solve such problems, and its purpose is to easily manage physical properties,
The objective is to provide a plating bath with a long liquid life.

"Means for Solving Problems" The present invention provides a plating bath containing a complexing agent for metal ions in an aqueous solution containing Nickel ions, iron ions, a PH buffer for these metal ions, a PH adjuster, and a surfactant. It is characterized by the simultaneous addition of malate and citrate, which have the ability to effectively open up nickel and iron ions.

In the present invention, the malate concentration used is 0, I Om
o9/9~1. Omof2/9. , the citric acid concentration is O
, lomoI2/42-0.8mo[/e and the desired malate 1 degree is 0.30mof2/e~0.7mo&
/g, tartaric salt concentration is 030moβ/e~0.6mo
ff/g. This is because if the complexing agent concentration is too low,
It lacks the stability targeted by the present invention, and malate is 0.7
moβ/! above and citrate is 0.6 moff/f
If it exceeds f, it has the disadvantage of becoming greedy.

[Function 1] From the above, the free ions in the plating bath are appropriately adjusted, the composition of the plating film is kept constant, and precipitation due to oxidation of iron ions can be prevented, thereby greatly improving the life of the solution.

Hereinafter, the characteristics of the electroplating bath according to the present invention will be explained as comparative examples and
This will be explained using an example.

[Comparative Example] A copper plate was degreased, washed with water, immersed in acid, and washed with water, and an iron-nickel alloy m-based film was formed thereon using the following plating bath composition and plating conditions.

(Plating bath composition) Nickel sulfate 1.15 mo12/Q Nickel chloride 0.10 noβ/e Boric acid
0.24 mo12/Q ferrous sulfate
0.054 mo12/12 saccharin
0.50 g/f2 Sodium lauryl sulfate 0.20 g/ff (plating conditions) Current density...0.4Adm2 1 Valley (Chang ・ ・ ・ ・ 35 ℃
PF (・ ・ ・ 2 60 under the condition of 6 or more
A plating film of 8 μm was obtained.

When this film was magnetically measured using a VSM measuring device, the coercive force was 0.50e and the saturation magnetic flux density was 8000G.

The stability of the plating bath was confirmed as follows.

After pre-treating a copper plate (50x50x2mm), it was plated for 60 minutes and plating was repeated one after another. This was repeated 12 times and the holding force was measured. The results are shown in FIG. It can be seen that the holding power gradually increases. Furthermore, when the plating bath was observed after the work was completed, a brown precipitate was observed at the bottom of the bath. This is due to the oxidation of iron ions and is thought to be the cause of the increase in retention.

In addition, at our head office, we have confirmed that when the temperature is above 40°C, iron ion oxidation rapidly progresses, causing the magnetic properties to deteriorate.

The above results revealed that the magnetic properties were unstable and the bath life was extremely short.

[Example 11 An iron-nickel alloy magnetic film was formed in the same manner as in the comparative example using a plating bath with the following composition 6 (Plating bath composition) 1iiiif M Nickel 1.15 mo
! ! , /12' Nickel chloride 0.10
mail/12 boric acid 0.24
mo(2/E ferrous sulfate 0°054
mog/sodium cylinlate 0.50' m
ap! /E Sodium citrate 0.40 moQ
/Q Saccharin 0.50 g/ff
Sodium lauryl sulfate 020 g/I2 When the magnetic properties were investigated in the same manner as the comparative example, the first plating film was °;
The saturation magnetic flux density was 8200G at a coercive force of 0130e.

Regarding the stability of the plating bath, as shown in FIG. 2, the holding force showed a very stable history.

After that, plating was carried out once every -day and this was repeated for -6 months.The results were good, showing stable holding power.
No sediment was found in the bathtub.

Furthermore, with one main store composition, the temperature remained stable even though the temperature was raised to 80°C.

From the above results, it was confirmed that the 1M1 gas characteristics are extremely stable and the liquid life is also extremely long.

[Example 2] The iron-nickel alloy plating bath of the present invention was studied as a decorative and anticorrosive plating.

(Mejikin valley composition) Nickel sulfate 0.40 mol/Nickel silchloride 0.25 mol/g.

Boric acid 0.75 maI2/12 saccharic acid No.9 loss 0. 03
5 mol/12 sodium malate 0.50
moβ/ε Sodium citrate 0.35
mo9! /12 Saccharin 0.50
g/Q Sodium lauryl sulfate 0.20g/n (
Plating conditions) Current density = 0.4 Adm" (6 temperature...35°C P) l...2.6 A brass watch case was pretreated and plated to a thickness of 5 um under the above plating conditions.

As a result, this alloy plating had excellent gloss and smoothness, and a high decorative effect was obtained.

In addition, the iron content in the plating film is approximately 25%, which helps reduce the cost of the anode metal. It was found that &Ilφ has excellent spreadability and can be applied to various products.

[Effects of the Invention] As described above, the iron-nickel alloy plating bath of the present invention provides stable plating properties over a long period of time,
Moreover, it became possible to obtain a high-quality plating film.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the change in the number of plating times and the holding force of the plating bath used in the comparative example. FIG. 2 is a diagram showing changes in the number of times of plating and the holding force in the plating bath used in Examples. that's all

Claims (1)

[Claims] Nickel ion, iron ion, pH of these metal ions
An iron-nickel alloy plating bath characterized in that an aqueous solution containing a buffer, a pH adjuster, and a surfactant contains malate and citrate as complexing agents for the metal ions.