The electroplating behavior of nanocrystalline CoNiFe soft magnetic thin film with high saturation magnetic flux density (Bs>2.1 T) and low coercivity (Hc) was investigated using cyclic voltammetry and chronoampero...The electroplating behavior of nanocrystalline CoNiFe soft magnetic thin film with high saturation magnetic flux density (Bs>2.1 T) and low coercivity (Hc) was investigated using cyclic voltammetry and chronoamperometry methods in conjunction with the scanning electron microscopy (SEM/EDX). The results show that, under the experimental conditions, the co-deposition of CoNiFe film behaves anomalously due to the atomic radii of iron series elements following the order of rFe>rCo>rNi. In the case of lower electroplating current density, the co-deposition of CoNiFe film follows a 3-D progressive nucleation/growth mechanism, while in the case of higher electroplating current density, which follows a 3-D instantaneous nucleation/growth mechanism. Meanwhile, the change of nucleation mechanism of CoNiFe film with electroplating current density was interpreted theoretically in the light of quantum chemistry.展开更多
Cobalt-molybdenum （Co-Mo） amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters,only the concentration ratio of m...Cobalt-molybdenum （Co-Mo） amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters,only the concentration ratio of molybdate to cobalt ions （[MoO4^2-]/[Co^2＋]） was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques,which was used to examine the voltammetric response,revealing that cobalt-molybdenum codeposition depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response,various cobalt-molybdenum alloy thin films obtained from different [MoO4^2-]/[Co^2＋] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations （[MoO4^2-]/[Co^2＋]≈0.05） applying low deposition potentials. Moreover,the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case,the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric current-time （j-t） deposition transients. The films with amorphous structure were obtained. The hysteresis loops suggested that the easily magnetized axis was parallel to the surface of the films. A saturation magnetization of 137 emu·g^-1 and a coercivity of 87 Oe of the film were obtained when the deposition potential was -1025mV,and [ MoO4^2-]/[Co^2＋] was 0.05 in solution,which exhibited a nicer soft-magnetic response.展开更多
文摘The electroplating behavior of nanocrystalline CoNiFe soft magnetic thin film with high saturation magnetic flux density (Bs>2.1 T) and low coercivity (Hc) was investigated using cyclic voltammetry and chronoamperometry methods in conjunction with the scanning electron microscopy (SEM/EDX). The results show that, under the experimental conditions, the co-deposition of CoNiFe film behaves anomalously due to the atomic radii of iron series elements following the order of rFe>rCo>rNi. In the case of lower electroplating current density, the co-deposition of CoNiFe film follows a 3-D progressive nucleation/growth mechanism, while in the case of higher electroplating current density, which follows a 3-D instantaneous nucleation/growth mechanism. Meanwhile, the change of nucleation mechanism of CoNiFe film with electroplating current density was interpreted theoretically in the light of quantum chemistry.
基金Project(52174303)supported by the National Natural Science Foundation of ChinaProject(2125026)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Cobalt-molybdenum （Co-Mo） amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters,only the concentration ratio of molybdate to cobalt ions （[MoO4^2-]/[Co^2＋]） was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques,which was used to examine the voltammetric response,revealing that cobalt-molybdenum codeposition depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response,various cobalt-molybdenum alloy thin films obtained from different [MoO4^2-]/[Co^2＋] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations （[MoO4^2-]/[Co^2＋]≈0.05） applying low deposition potentials. Moreover,the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case,the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric current-time （j-t） deposition transients. The films with amorphous structure were obtained. The hysteresis loops suggested that the easily magnetized axis was parallel to the surface of the films. A saturation magnetization of 137 emu·g^-1 and a coercivity of 87 Oe of the film were obtained when the deposition potential was -1025mV,and [ MoO4^2-]/[Co^2＋] was 0.05 in solution,which exhibited a nicer soft-magnetic response.
