Zn-Cr electrodeposition behavior was studied in the sulfate solutions containing acyclic polymer additives such as gelatin and polyethylene glycol (PEG) at 2kA/m2. The electroreduction of Cr ions into metal was promoted by the addition of gelatin as well as PEG to the solution, and the deposits contained Cr in both trivalent and metallic states. The ratio of metallic Cr to total Cr changed depending on the molecular weight and the concentration of gelatin and PEG added to the electrolytic solution. Further, the cathode potential shifted to the less noble direction with increasing molecular weight or concentration of these additives. The ratio of metallic Cr in deposits showed a close relation with the cathode potential, and reached a maximum value at approximately −1.2V (vs. NHE). At potentials less noble than −1.2V, the deposits contained a considerable amount of trivalent Cr, which was the product of hydrolysis resulting from the accelerated hydrogen evolution by both the decomposition of water and the decrease in overpotential for hydrogen due to increase in Cr content in deposits.
Charge-discharge behaviors for tin-12% iron alloy films on electrolytic copper foils prepared by electroplating, which were low cost and made of environmentally friendly alloy, were investigated for X-ray a diffraction measurement, cyclic voltammetry and charge-discharge tests. Tin-12% iron alloy plating anodes showed a discharge capacity of 374 mAh/g after 50 cycles with metallic lithium as counter electrodes. From the results of cyclic voltammograms for tin-12% iron alloy plating anodes, the current value for lithium deposition increased around 0.26 V in the first cycle and increased around 0.68 V in the second cycle. The current value for lithium deposition in tin plating anodes increased around 0.66 V in the first cycle. These results suggested that iron was separated from tin-iron alloy plating film in the first charge and electric conductivity of tin-lithium intermetallic compounds formed bycharge-discharge reactions was improved by the dispersion of iron particles between these compounds. At a discharge rate of 5C(50 A/m2) tin-12% iron alloy plating anodes showed a discharge capacity of 285 mAh/g after 50 cycles and was applicable for high discharge rate. A coin-type cell(CR 2032) with a tin-12% iron alloy plating anode and a LiCoO2 cathode showed a discharge capacity of 273 mAh/g and coulombic efficiency of 90.4% after 95 cycles in charge-discharge tests at a constant charge capacity of 302 mAh/g. Therefore, tin-12% iron alloy plating anodes can be expected to substitute for carbon as high capacity anodes for advanced lithium secondary batteries.
Anodic oxidation behavior of sulfamate ions during the electrodeposition of Ni from sulfamate baths was investigated using Pt, Ni and Ni-S anodes. The following results were obtained ; (1) The oxidation products of sulfamate ions showed an absorption peak at 245-250 nm in UV spectra and the absorbance was changed depending on the anode potential. (2) At potentials less noble than 0 V vs. NHE, no anodic oxidation products were formed, while the amount of anodic oxidation products was significantly increased when the anode was polarized to a greater noble potential than 0 V. (3) In the presence of Cl- ions in the baths, the Ni-S anode was maintained at potentials less noble than 0 V under most electrolysis conditions. (4) The content of S in the electrodeposited Ni was increased in proportion to the concentration of the anodic oxidation products in the baths. (5) By increasing the content of S, the deposited Ni became finer in size and showed the feature of unoriented dispersed type with high hardness.
System In Package (SIP) technologies have been extensively studied to realize high-density packaging and high operation performance. A key technology for 3D chip stacking as a shortest connection is required. We found that void free copper filling for an interposer having a relatively large vias was achieved by controlling the additives and current waveform.
The effects of zincate pretreatment, heat aftertreatment and laser irradiation on the adhesion of electroless Ni-P coating onto aluminum and aluminum alloys were examined. On the adhesion, it was found that the precipitation state of the zinc in the zincate treatment had a much greater influence than the heat aftertreatment.