Atmospheric pressure plasma treatment has potential as a pretreatment of material for bonding strength improvement. To produce a textured surface on a copper substrate, we specifically examined atmospheric pressure plasma treatment. The surface-morphology change of plasma treatment alone was very slight, but that of plasma treatment with stearate acid films created a textured surface with fine protrusions of several tens of nanometers, as observed using AFM or TEM. Furthermore, the chemical components of the textured surface were analyzed using AES. Results demonstrate that the fine protrusions consist mainly of Cu₂O, but flat parts of the textured surface were only slightly oxidized. The stearate acid film prevents oxidation on flat parts of the copper substrate. Subsequent plasma treatment formed selective oxidized fine protrusions on the copper. Atmospheric pressure plasma treatment readily promotes metal oxide Cu₂O by the formation of oxygen atomic radical. Results of surface measurements and analyses suggest that the combination of atmospheric pressure plasma treatment with stearate acid films produced a nanoscale textured surface with fine protrusions on copper substrates.

Electrical plating of copper and zinc is actively used as anticorrosion plating for surface treatment of bases for decorative plating. Pyrophosphoric acid is used industrially as a complexing agent for these metals in only a few cases, but pyrophosphoric acid is an excellent complexing agent in terms of uniform electrodepositivity and bath stability. Moreover, reports have described the use of organic additives such as amino acids for zinc pyrophosphate plating.

This study used electron microscopy, AC impedance method, quartz crystal microbalance method, and charge transfer and mass change for zinc and copper electrodeposition were analyzed to investigate the effect of L-histidine addition to a bath in which pyrophosphoric acid is a complexing agent. Results of copper electrodeposition confirmed that an increase in the charge transfer resistance and a decrease in the amount of electrodeposition were ascribed to L-histidine adsorption. Results of zinc electrodeposition confirmed that increase of the electrode area because of the change in surface area caused the reduction of the charge transfer resistance, and increase of the electrodeposition amount.