Shun-ichi Yoshimura

Preferred orientation and morphology of electrodeposited iron from iron(II) chloride solution

Abstract The effects of each electrolytic condition on current efficiency, Vickers hardness, crystal structure and crystal morphology were studied with respect to the electrodeposited iron films obtained from iron(II) chloride solution. The temperature of the solution was varied from 20 to 60°C, the pH value of the solution varied from 0 to 2, and the applied current density varied from 5 to 100 mAcm −2 . Higher current efficiency was obtained at a higher solution temperature, higher pH value of the solution and lower applied current density. The films thus obtained showed a lower Vickers hardness and a preferred orientation of the (110) plane. Lower current efficiency was obtained at a lower solution temperature, lower pH-value of the solution showed a higher Vickers hardness, and a preferred orientation of the (211) plane. It is thought that these tendencies are related to the contribution of the hydrogen evolution reaction as a side reaction.

Microhardness and crystal structure of iron films electrodeposited from iron (II) chloride solution

The relationship between microhardness and crystal structure was studied with respect to electrodeposited iron films obtained from iron(II) chloride solution under various electrolytic conditions. The deposits with a lower microhardness showed a preferred orientation of the (110) plane, and the microhardness and the orientation index of the (110) plane were represented by an approximately linear relationship. In order to obtain the deposits with a lower microhardness, it is necessary to electrolyze under a lower current density, at a higher temperature and in the solution with higher pH. The deposits obtained showed large crystal grains having a preferred orientation of the (110) plane. A dependence was revealed betweenb microhardness and crystal structure of the deposits

Microhardness and crystal structure of electrodeposited iron films from iron(II) chloride solution

The relationships between microhardness and crystal structure were studied with respect to electrodeposited iron films obtained from iron(II) chloride solution under various electrolytic conditions. The deposits with a lower microhardness showed a preferred orientation of the (110) plane and the microhardness and the orientation index of the (110) plane were represented by an approximately linear relationship. In order to obtain the deposits with a lower microhardness, it is necessary to electrolyze at a lower current density, at a higher temperature and in a solution with higher pH. The deposits obtained showed large crystal grains having a preferred orientation of the (110) plane. A clear dependence between microhardness and the crystal structure of the deposits was presented.

Electrodeposition of palladium from ethylenediamine-palladium (II) complex solutions by direct current and pulsed current electrolysis.

Electrodeposited palladium films were obtained by the use of the direct current and pulsed current electrolysis in ethylenediamine-palladium (II) complex solutions. The effects of electrolysis parameter on the current efficiency, hydrogen content and morphology of palladium deposits were investigated under varying conditions of electrolysis. Direct current electrolysis, increases in current density resulted in a black, dusty deposit reduced current efficiency and higher hydrogen content. The adoption of pulsed current electrolysis made it possible to obtain smooth deposits of fine grain and to lower the hydrogen content markedly. This behavior is thought to be due to the fact that the pulsed current density (Ip) and off-time (Toff) have a considerable affect on the deposits. The fine grain deposits were obtained by inducing a large overpotential as a result of increasing Ip. It would seem that the smooth deposits were due to the occurrence of Toff, which had the effect of depressing the concentration polarization on account of the mass transport of metal ions on electrode surface. In addition, it is thought that the hydrogen is removed from the deposits during Toff.