The plated films of electroless Cobalt deposited from the following 4 kinds of baths were examined macroscopically, microscopically, and by roughness tester; and the effects of fundamental conditions of the bath on the properties of films were investigated.
(1) CoSO₄ 0.07mol/l, NaH₂PO₂ 0.2mol/l, Na-Citrate 0.2mol/l, (NH₄)₂SO₄ 0.6mol/l, pH=9-10 (A-C Type bath)
(2) CoSO₄ 0.08mol/l, NaH₂PO₂ 0.2mol/l, Na-Tartrate 0.5mol/l, (NH₄)₂SO₄ 0.6mol/l, pH=9-10 (A-T Type bath)
(3) CoSO₄ 0.05mol/l, NaH₂PO₂ 0.2mol/l, Na-Citrate 0.2mol/l, H₃BO₃ 0.5mol/l, pH=7-8 (C-C Type bath)
(4) CoSO₄ 0.05mol/l, NaH₂PO₂ 0.2mol/l, Na-Tartrate 0.5mol/l, H₃BO₃ 0.5mol/l, pH=9 (C-T Type bath)
The appearance of the deposit depended on the kinds and concentrations of complexing agents in the bath. Namely, types of the baths were arranged in descending order of the brightness of plated films as follows:
A-C>C-C>A-T>C-T
When the plating was carried out in the bath of the same composition, the film obtained had less bright appearance as the rate of deposition was greater.
The surface state of the plated film was worse as the film was more thick, in particular, the tendency was remarkable in the baths of tartrate type.
Ammonium sulfate present in ammoniacal alkaline baths improved the surface state of plated films. The optimum concentration of ammonium sulfate was 0.6mol/l. Though thiourea was an effective brightener for these baths, its optimum amount of addition depended on the type and pH of plating baths.

抄録全体を表示

Effects of the bath composition and addition agents on the electrodeposition of nickel have been studied by means of X-ray diffraction method. The orientation of the nickel deposits obtained from Watts, nickel sulfate and chloride baths and also from Watts bath containing addition agents has been analyzed by orientation index.
It was found that the nickel deposit from Watts and nickel sulfate baths generally represented (200) orientation, but the deposit from nickel chloride bath represented a tendency toward random orientation.
When Na-1, 5 naphthalene disulfonate or saccharin was added to Watts bath, the nickel deposit was (200) orientated in low D_K range, but was (200) and (111) orientated in high D_K range. However, other orientations such as (220) and (311) were found in thick deposit in high D_K range.
When thiourea was added to the bath, the deposit was (200) and (111) orientated and the orientation index of (111) was found to be larger in low D_K than that in high range.
In general, (200) orientation was only observed in the deposit obtained from the bath containing butynediol, coumarin, or formalin.
When Na-1, 5 naphthalene disulfonate+butynediol or saccharin+butynediol was used as an addition agent in the bath, orientation index of (111) was found to be very larger as compared with that of the deposit from the bath containing Na-1, 5 naphthalene disulfonate or saccharin.
When saccharin+thiourea was added to the bath, the orientation of the deposit was almost the same as that of the deposit from the bath containing thiourea.
There was observed (200) orientation only in the deposit from the bath containing acetic acid+butynediol.

抄録全体を表示

Although the bright and leveled copper deposits from cyanide baths are widely used in practical plating, there have been found less investigations on brightners and their effects of these deposits than those of nickel or acid copper plating deposits. The author has investigated on brightners of copper cyanide baths. In this paper, there are given the results of the brightening effects of copper cyanide baths; the investigations were carried out on the cathodes in Hull cell and Haring cell with about 60 kinds of organic and inorganic compounds as additives and under various plating conditions.
The results were summarized as follows.
1) The most effective brightners included the compounds containing easily freed sulfur, such as thiocyanide, thiosulfate, xanthogenate, etc. Good results were obtained from the baths containing these compounds over a wide range of cathode current density when agitation and periodic reverse current were applied in the bath of high temperature.
2) Among the inorganic compounds containing no sulfur, the compounds consisting of the elements belonging to the IIIB-VIB Groups of Periodic Table had good brightening effects. When their atomic weight was larger, they showed the better effects.
3) The organic compounds containing no sulfur had no brightening effects, but the effects were improved in some degree when a large quantity of surface active agent was added.

抄録全体を表示