Abstract： Water vaporcondensation on metal surface causes corrosion and further affects the performance. In order to decrease this disadvantageous effect, in this paper, the coating of desiccant material (silica gel) to metal surface was proposed. The performance of this method was analyzed both by experiments and by theoretical investigation. Condensation time was adopted as the performance index. Experimental results indicate that desiccantcoated metal surface can effectively delay condensation time which is defined as parameter t. When the temperature difference between metal surface and the dew point is constant, t increases with the decrease of the dew point temperature.When the dew point temperature is constant, t increases with the increase of metal surface temperature. Then, the dynamic condensation process on metal surface was analyzed using the adsorption kinetic model. The diffusivity of water vapor is calculated, because t is affected by the diffusivity of water. The results show that the diffusivity of water vapor is affected significantly by the temperature of silica gel and the water vapor partial pressure. When the temperature of silica is constant, the water vapor diffusivity decreases with decreasing water vapor partial pressure. And when the water vapor partial pressure is constant, the water diffusivity decreases with decreasing temperature of silica, leading to a longer delay time of condensation.
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