Katsuhiko Tashiro

Nanoscale smooth interface maintained metallisation of polyimide using low concentration ozone micro–nano bubbles dispersed in water

Abstract In order to induce adhesion of electroless CuNiP deposition to polyimide (PI) film substrate, surface modification of PI film with an aqueous dispersion of ozone micro–nano bubbles was investigated. The treatment resulted in maximum adhesion strength of 1·14 kN m−1 for a treatment time of 5 min. Structure of the modified PI surface, the PI/plating interface, mechanism for adhesion and laminate properties were analysed. Despite increased adhesion, surface roughness of PI was not notably changed by the ozone induced surface modification. Contact of PI surface with high ozone concentration micro–nano bubbles with sufficient frequency was found to modify the surface with a low total ozone concentration of the aqueous dispersion. Cross-sectional observation of the interface suggested that formation of a thin nanoporous anchor layer on the PI surface was responsible for plating adhesion. This method provides an environment friendly and improved process for plating on PI using low concentration ozone treatment.

Metallisation on ABS plastics using fine-bubbles low ozonated water complying with REACH regulations

Traditionally, a highly concentrated mixed solution of chromic acid and sulphuric acid has been used as an etchant for electroplating on ABS plastics. However, this etchant is hazardous and the subject of impending legislation. Therefore, the fine-bubbles low ozonated water treatment as an alternative to the chromic acid etching process has been investigated. Adhesion strengths of 0.9–1.0 kN m−1 were obtained for treatment of 30 min. From the observation of surface morphology, dimples of several hundred nanometres were formed after surface modification. Cross-sectional observation of the interface suggested that formation of a thin nano-porous anchor layer on the ABS surface was responsible for plating adhesion. This method with low ozonated water treatment provides an environmentally friendly process for plating on ABS.

Stress control in high speed nickel plating by use of step control current

Abstract Plating stress in nickel plating increases with high current density. A remedy for this has been demonstrated by using a step control method through combining plating at 20 A dm−2 (low current density) and 40 A dm−2 (high current density). Internal stress could be reduced in comparison to plating at a fixed current density by the initial formation of crystals at a 20 A dm−2 low current density, such that a state of low stress was maintained by epitaxial growth.