Abstract: The scaling process of calcium carbonate on a low-energy heat transfer surface－electroless
plating surface was investigated in a simulated cooling water system. Owing to the very low
surface energy, the electroless plating surface exhibited less scaling susceptibility. A
longer induction period and a lower scaling rate were obtained on the low-energy surface
compared to copper surface under identical conditions. The calcite particles obtained on
the electroless plating surface during the induction period were larger in size than those
on copper surface because fewer crystals formed and grew at the same time on the low-energy
surface. With increasing surface temperature, the induction period reduced and the scaling
rate increased for the low-energy surface. When initial surface temperature was fixed, an
increase in fluid velocity would reduce the induction period and increase the scaling rate
due to the diffusion effect. However, when the heat flux was fixed, an increase in fluid
velocity would decrease the surface temperature, and lead to a longer induction period and
a lower scaling rate. The removal experiments of calcium carbonate scale indicated that
during post induction period, the detachment was not obvious, while during the induction
period, apparent removal of crystal particles was obtained on the electroless plating
surface owing to the weak adhesion force. The more frequently the transient high
hydrodynamic force acted, the more the detached crystal particles were.

Key words: scaling, induction period, removal, electroless plating surface

摘要： The scaling process of calcium carbonate on a low-energy heat transfer surface－electroless
plating surface was investigated in a simulated cooling water system. Owing to the very low
surface energy, the electroless plating surface exhibited less scaling susceptibility. A
longer induction period and a lower scaling rate were obtained on the low-energy surface
compared to copper surface under identical conditions. The calcite particles obtained on
the electroless plating surface during the induction period were larger in size than those
on copper surface because fewer crystals formed and grew at the same time on the low-energy
surface. With increasing surface temperature, the induction period reduced and the scaling
rate increased for the low-energy surface. When initial surface temperature was fixed, an
increase in fluid velocity would reduce the induction period and increase the scaling rate
due to the diffusion effect. However, when the heat flux was fixed, an increase in fluid
velocity would decrease the surface temperature, and lead to a longer induction period and
a lower scaling rate. The removal experiments of calcium carbonate scale indicated that
during post induction period, the detachment was not obvious, while during the induction
period, apparent removal of crystal particles was obtained on the electroless plating
surface owing to the weak adhesion force. The more frequently the transient high
hydrodynamic force acted, the more the detached crystal particles were.

关键词: scaling;induction period;removal;electroless plating surface