Abstract
Optimum particle dispersion is an essential feature for composite coatings carried out on the autocatalytic electroless nickel plating platform. In this regard, the potential influence of an anionic surfactant, sodium dodecyl sulphate (SDS), on the dispersion stability of a ceramic, yttria stabilized zirconia (YSZ), in an acidic electroless nickel solution of pH 4.9 has been assessed in this study. Ultra violet-visible spectrophotometry was used in accordance with the Beer-Lambert law (–log (I 1/I 0) = A) to evaluate the rate of YSZ particle sedimentation in electroless nickel solutions with and without surfactant. Measurement of the particles' zeta potential at each surfactant concentration was conducted in parallel with the UV-vis tests with the aim of establishing the interaction among the surfactant, YSZ particles, and electroless nickel solution. A slight increase in the negative magnitude of the particles' zeta potential indicated the adsorption of SDS onto the particles' surface and a possibility of contributing to its stability. However, the surfactant's inability to counteract an electroless nickel solution–induced particle accretion resulted in the observation of poor YSZ particle stabilities at all the investigated surfactant concentrations.
Acknowledgments
The authors wish to thank Mr. Stephen Paterson for the electronic copy of the ultraviolet-visible spectrophotometry chart. Ms. Zurine Hernandez of the Centre for Timber Engineering is also sincerely acknowledged for the availability of the Malvern Zetasizer equipment.
Notes
a Polydispersity index = 0.161.
b Polydispersity index = 0.171.
a Average polydispersity index (Pdi) = 0.2026.
b Average polydispesity index (Pdi) = 0.2524.
c Size not reported by Zetasizer at the specified time.