Co-Ni alloy films were potentiostatically deposited on a polycrystalline copper plate and a stainless steel plate from a sulfate bath. In the electrodeposited Co-Ni alloy, an α-phase formed in all compositions and an ε-phase coexisted from 0 to about 40 at% Ni. In the mixed α and ε phase, numerous stacking faults between the ε layers and the α layers occurred within one grain. Film grain size was affected by film composition independent of cathode potential and current density. Substrates crystallinity affected grain size and film surface morphology. Films on the polycrystalline copper plate grew epitaxially and showed a different morphology for the crystal face. Films on the stainless steel grew randomly and showed a ragged surface.
The microstructure of Co-Fe alloy films electrodeposited on a polycrystalline copper substrate were studied by using XRD and observed by SEM and TEM. Film phase structure depended on the alloy composition alone bcc-α, fcc-γ and hcp-ε phases spread compare to the quilibrium phase at room temperature Film grain size depended on the alloy composition independent of potential and current density The grain size of the mixed phase of a and γ and ε at 18at%Fe was the finest of all films The grain size of the mixed phase of γ and ε increased with the Co content, while the grain size of the α phase increased and with Fe content
Electrochemical conditions for improving the resistance to active corrosion of SUS 304 stainless steel using potentiostatic pretreatment in a total fluoride concentration of 0.5kmol·m-3 solution with various pH at 303K were studied. Active corrosion susceptibility after treatment was evaluated by measuring the self-activation time, τa, in deaerated 1.0kmol·m-3 sulfuric acid solution at 303K. In an acidic fluoride solution, maximum stability is obtained at -0.4V (SCE) of pretreatment potential in a solution pH of 1.8. XPS analysis of treated steels showed that Cr content extensively increased in the oxide layer of passive film, improving resistance to active corrosion, and F- ions located in the hydroxide layer, assuming that passive film consists of three layers, hydrocarbon contaminant covering a hydroxide layer of Cr and an underlying Cr and Fe oxide layer. In a neutral solution, maximum stability is obtained at 0.6V (SCE) of pretreatment potential in a solution pH of 8.6. Cr enrichment was not seen in the passive film by XPS. Anodic polarization measurements suggest that structural changes in the passive film take place at 0.6V (SCE). In an alkaline solution, however, treated steel can not acquire a high resistance to active corrosion over a wide range of potentials for pretreatment. XPS showed that the hydroxide layer of passive film was very thin compared to that formed in an acidic solution and F- ions were entirely absent in the passive film.
Organic polymer plating properties of 6-diallylamino-1, 3, 5-triazine-2, 4-dithiol monosodium (DAN) were studied for NaNO2 supporting electrolytes. Supporting electrolytes cause polymer film to form or not. NaNO2 electrolytes particularly accelerated the formation rate of polymer plating. The accelerating effect of NaNO2 was confirmed comparing plating potentials in the presence of NaNO2 and NaCO3. NO2- anions are electrochemically oxidized to yield NO2·radicals that react with DAN to yield thiyl radicals. DAN thilyl radicals between molecules, yielding disulfide bonds that grows into polymer films. Organic polymer plating films contained disulfide and monosulfide bonds produced by the reaction between allyl groups and thiyl radicals and network chains.