Titanylphthalocyanine (TiOPc) thin films with various crystallinity were prepared by vacuum deposition, changing substrate temperature (Tsub) from -160 to 200°C, and their photoconductivity was examined. Two types of cells with sandwich and surface type electrodes were fabricated for photoconductivity measurements. Surface morphology of the TiOPc films was examined by STM observation, All the TiOPc films deposited at a Tsub of above 20°C were polycrystalline (β-form), and the film crystallinity increased with an increase in the Tsub. But, TiOPc films deposited at low Tsub's were quasi-amorphous or amorphous. Photoconductive sensitivity of the TiOPc thin films increased with a decrease in the Tsub. STM observation indicated that the surface of films deposited at low Tsub's was smooth, while irregular at high Tsub's. A molecular configuration model for the TiOPc films was proposed to explain experimental results on the crystallinity and photoconductivity of the TiOPc films.
In an alkaline zincate bath, the electrode reaction of Zn deposition proceeds in accordance with the following equations; Zn(OH)42-→Zn(OH)2+2OH- and Zn(OH)2+2e→Zn+2OH-. It is controlled by the charge-transfer reaction and the diffusion of Zn(OH)42- ion towards the interface from the bulk, while Co deposition is controlled by the diffusion of Co (tetren)2+ ion. The influence of plating variables on the composition of deposited alloys was examined. As a result, Zn-Co alloy deposition from this zincate bath was found to be an anomalous codeposition, in which Zn, the electrochemically less noble metal, deposits preferentially. The mechanism of anomalous codeposition, that is, the preferential deposition of Zn was explained on the basis of Zn (OH)2 film formation. In the absence of additives, columnar crystals perpendicular to the substrate grew remarkably, while the addition of brighteners notably improved the surface state of alloy deposits, and their morphology changed to a smooth and fine structure. Moreover, the additives caused the preferred crystal orientation of alloy deposits. The corrosion resistance of Zn-Co alloy deposits was highly superior to that of Zn deposits, and the performance was much improved when chromated.
Copper was codeposited with Sn in a weakly alkaline bath containing sodium tripolyphosphate as a complexing agent. The effect of plating variables on the composition of electrodeposited Cu-Sn alloys was then examined. The Cu content in the deposit was higher than that in the bath under all operating conditions, and increased with decreasing current density or increasing bath temperature. The results obtained indicate that the Cu-Sn alloy plating from tripolyphosphate baths is of the regular codposition, in which Cu behaves as a noble metal and Sn as a less noble one. The surface appearance of the alloy deposits varied from copper-colored to golden-yellow, then silvery white with increasing Sn content. Bright and silvery white speculum deposits were obtained by using peptone as an additive. X-ray diffraction measurements have revealed that speculum deposits consist mainly of an η phase, and a phase, which appears and is stable only at elevated temperatures and low current densities. The hardness of the electrodeposited Cu-Sn alloys was high in the range of speculum composition. Speculum coatings had excellent resistance to some kinds of chemical attack and their corrosion resistance was slightly superior to that of bright Ni coating. In conclusion, the electrodeposited speculum seems to be applicable as a substitute for Ni plating.
The Effect of inclusion on room temperature softening of copper film electrodeposited from ethylenediamine complex baths was investigated along with its mechanism. Copper film electrodeposited from ethylenediamine complex baths under optimal plating conditions was found to increase in crystallite size and decrease in microhardness with the preservation of room temperature. This phenomenon was only found in cases of small crystallite size, containing a small quantity of inclusion at the time of electrodepositing.
Nickel was electroplated with direct current, sinusoidal current, and three kinds of pulsed current. A ferroxyl test was conducted to measure the porosity of deposits. When the pulse waveform was composed of 16ms deposition and 4ms rest, porosity was about 1/10 less than porosity of deposits by direct current. Then a solid state switching circuit was designed and tested to provide this pulse waveform by connecting in series with an ordinary power supply.
There are many research reports on the relation between abrasion resistance and electrolytic conditions and kinds of aluminum alloys in hard anodization. But reports on the relation between electrolytic wave forms porous layer structure and hardness, and abrasion resistance are few. So we studied the effects of electrolytic wave forms on them. The waves examined were direct current, superimposed alternating current to direct current, periodic reverse current and interrupted current. The following results were obtained: (1) The harder the anodized coating, the better the wear resistance. (2) Interrupted current is the best electrolytic wave form in terms of hardness and wear resistance for anodized coatings. (3) A regularly porous layer is not clearly recognizable in this anodized coating.
The inhibiting effect of poly-4-vinylpyridine (P4VP) on the corrosion of mild steel and pure iron in hydrochloric acid and perchloric acid was studied. P4VP showed good inhibiting effect, but moleculer weight dependance of the inhibiting effect on the corrosion of mild steel was observed. The addition of chloride ion to perchloric acid affected the inhibiting effect of P4VP. Polarization measurement showed that P4VP suppressed both anodic and cathodic reactions in hydrochloric acid. XPS analysis showed the presence of P4VP and oxide and chloride of iron in the surface layer.
Porous layer growth on anodized coatings develops not only from internal stress but also varies according to residual stress on the anodized coating. The results of observation of the deformation of curvatures of foils anodized one side and on both sides were as follows. 1) Internal stress is subject to tensile stress as the porous layer grows. 2) Curvature deformation is large in cases of high bath temperature or thick layer, but isn't always proportional to the strength of internal stress.