Shoji Ichihara

Application of emulsion of dense carbon dioxide in electroplating solution with nonionic surfactants for nickel electroplating

Abstract An electroplating reaction using nickel was carried out in an emulsion of dense carbon dioxide (CO2) and an electroplating solution with nonionic surfactants. The current efficiency and electrical resistance values were measured as a function of CO2 volume fraction in the emulsion with three kinds of surfactants. These results show that dense CO2 beyond the critical point of CO2 is effective to form an emulsion for the electroplating reaction. The nonionic surfactant octa(ethylene oxide) dodecyl ether, two kinds of poly (ethylene oxide)-b-poly (propylene oxide) with molecular weights of 745 and 950, respectively, were employed for emulsification. Moreover, a hydrophilic CO2-philic balance of the surfactants strongly influences on the stability of the emulsion. On the basis of the electrical conductivity measurements, the emulsion was classified into a CO2 in water (C/W) type with the CO2 volume fraction ranging from 0 to 80%. Compared to electroplating from the only solution, higher quality nickel films have been prepared by this method. The nickel films that were produced have a higher uniformity, a smaller grain size (sub-100 nm), and a significantly higher Vickers hardness.

Preparation of carbon materials with coral-like continuous pores using miscible polymer blends

Structurally new coral-like carbon materials with interconnected pores were prepared from miscible polymer blends of novolac type phenolic resin (PhN) and poly(methyl methacrylate) (PMMA). The carbons obtained had BET surface areas of 560 m2 g−1 without activation and a relatively large pore volume in the region over the micropore range.

Electroless plating of Ni thin films using foam of electrolyte

Electroless plating of Ni thin films was achieved in foam of electroplating solution in place of electroplating liquid. Commercial hypophosphite-based solution for Ni electroless plating was added with a surfactant of sulfuric acid monododecyl ester sodium salt (SDS) and bubbled with nitrogen gas to produce airy foam. Ni thin films were deposited by immersing iron substrates in the foam. Although stationary foam was inconvenient for electrodeposition by itself, film growth was enhanced by generating a flow of foam using substrate rotation and by adding SDS to a concentration of 0.1 to 0.3 wt %. No defects attributed to pinholes were observed on the film surface. This method was effective in reducing the net amount of plating solution necessary for film deposition.