The activation of steel with colloidal
titanium phosphate in the phosphating process was studied. The mechanism of the
activation has been clarified.
The colloidal solution contains disc-shaped
particles of the chemical composition
Sam active 211 these particles are adsorbed on
the metal surface during the activation period. When exposed to the zinc
phosphating solution, sodium ions on the surface of the titanium phosphate
particles, having a surface consisting of zinc phosphate. Act as nucleation agents
during the zinc phosphating.
The disc-shaped particles are predominantly
adsorbed with the flat surface against the metal surface this cause orientation
of the zinc phosphate crystals which are nucleated on the titanium phosphate
particles. The absorbed titanium phosphate particles can also affect the
composition of the zinc phosphate layer.