Cu 99.99mass% (4N) and Cu 99.9999mass% (6N) copper source metals were used for vapor deposition to consider the effects of the purity of the source metal on the photochemical etching and electroplating of vapor deposited copper. In comparison to film deposited using a 4N copper source, the film deposited using a 6N source exhibited superior etching pattern wall smoothness in photochemical etching and was free from dendrite growth in nickel plating. X-ray diffraction analysis showed no difference in copper crystal orientation between films formed with the 4N and 6N sources. Sputtering AES however, showed that there was less oxygen content in the copper surface deposited using the 6N copper source.
Dendrite growth and the method of preventing the dendrite growth in nickel electroplating were studied on photochemically etched patterns of vapor depositing copper using a 99.99mass% (4N) copper source. Soft chemical etching and increasing the plating power source ripple were found to be effective in preventing the dendrite growth. No dendrite growth with copper pattern formed using a 6N copper source or rolled or electrodeposited copper foil. It was found that copper patterns formed with a 6N copper source had higher resistivity in high temperature and high humidity testing than patterns formed with a 4N copper source.
Co-Fe-P soft magnetic films for thin film heads were prepared by electroplating. The amorphous phase was obtained at a current density of 5mA/cm2, and the crystal phase at 20mA/cm2. The values of Bs in the amorphous phase was 1.2T and of He 4Oe. The value of Bs in the crystal phase was 1.8T and of He 27Oe. Co-Fe-P crystal/amorphous multilayered films were fabricated by pulsating current between 5 and 20mA/cm2. When one layer was about 100-200nm thick, the values of Bs and He were about equal to the mean values of the crystal and amorphous phases. A layer of 10nm thick had excellent soft magnetic properties; Bs did not decrease (1.6T), but the He was low (6Oe) and close to that of the amorphous film.
Fe-W amorphous alloy films were prepared on an iron substrate by an electroplating method. The hardness of the heat-treated film was greater than 2, 000 (Hv/50g), according to the Vikers hardness test. By coating the surface of a conventional end-mill with this Fe-W plating film, a cutting tool with very high anti-wear properties can be obtained. This hardening mechanism may be explained by the changes in the crystallographic structure of the plated Fe-W alloy film. The structure changed from crystalline to amorphous as the concentration of W in the film increases. At W concentrations of above 50wt%, the film becomes amorphous. This concentration is in agreement the concentration of an intermetallic compound that become very hard by heat-treatment.
According to our previous work on the corrosion behavior of zinc-nickel alloy electroplated steel sheets in aqueous solutions, corrosion induces the formation of grooves that reach to the underlying steel. The corrosion grooves, which are thought to be caused by corrosion cracking, may cause deteriorating in corrosion resistance. In the present study, a method for measuring the fracture strength of zinc-nickel alloy electroplating films was established as a part of fundamental study toward improving corrosion resistance through suppression of corrosion groove formation. Fracture strength was determined by detection of acoustic emissions generated by film cracking during tensile testing of specimens. The fracture strength of zinc-nickel alloy films varied depending on plating current density.
Bright silver coatings were obtained from silver-succinimide baths. The pH dependence on the rest potential of Ag electrodes and the cathodic polarization curve were measured to clarify the electrodeposition mechanism. The effects of pH, temperature, and the bath's silver concentration on surface appearance were evaluated using Hull Cell tests. The current efficiency and microscopic surface morphology were also examined. The bath composition and operating conditions most conductive to obtaining a mirror-bright surface on the electroplated silver were 0.45mol/L of CH3SO3Ag, 1.5mol/L of succinimide, 0.025mol/L of Na2B4O7, a pH of 10, and a 25°C bath temperature. Cathode current efficiency exceeded 90% at current densities between 10 and 20mA/cm2. It was estimated that the silver was deposited from Ag (C4H4O2N)2- complex ion and the process was controlled by the charge transfer in the bath.