M. Kitano et al., MORPHOLOGY AND GROWTH-MECHANISM OF ZNO PARTICLES ELECTRO-CRYSTALLIZEDON ZN IN AQUEOUS-SOLUTION, Journal of crystal growth, 166(1-4), 1996, pp. 1116-1120
Products made by the electrochemical reaction of 500 mu m thick Zn she
ets and 25 mu m thick Zn foils with distilled water at 20 degrees C ar
e investigated by scanning electron microscopy. X-ray diffraction, and
pH measurements of the water. The reaction goes through the following
processes: (A) the formation of formless ZnO layers: (B) the growth o
f spindle-like ZnO particles and the precipitation of octahedral beta-
Zn(OH)(2) particles, with increasing pH (Max = 8.4) that is caused by
the dissolution of the ZnO; and (C) the reduction of spindle growth wi
th decreasing pH, caused by the precipitation of Zn(OH)(2). The proces
ses are repeated, and the reaction ceases when the metal is completely
consumed. These cyclic processes appear as peaks in the pH/time-depen
dence curve.