Abstract:
A novel electroless process has been demonstrated in this investigation to coat the surface of flyash
particles with a conducting metal such as copper. The conventional electroless process has been
modified for this purpose by replacing the tin–palladium catalyst-system with the titania/ ultravioletradiation/
metal catalyst-system, where the metal is either copper or silver as demonstrated here. The
mechanism of copper coating of flyash particles in an electroless bath, using the novel methods of
surface-sensitization and surface-activation, has been systematically studied by monitoring changes in
the surface-morphology, surface-chemistry, and surface-structure of flyash particles using the scanning
electron microscope, energy dispersive analysis of X-rays, X-ray photo electron spectroscope, and X-ray
diffraction. It has been revealed that the novel electroless method involves coating the flyash particles
with titania photocatalyst via sol–gel, which acts as a surface-sensitizer under the ultraviolet-radiation
exposure for the subsequent surface-activation with the copper- or silver-clusters. The latter in turn acts
as surface-catalyst for the subsequent Cu-coating in an electroless bath. The proposed mechanism of
surface-sensitization and surface-activation of flyash particles using the novel catalyst-system has been
compared with that using the conventional catalyst-system.
