Research On The Effects Of Surface Properties On Ice Adhesion Strength

Ice adhering on surfaces not only can reduce the efficiency of refrigeration system, butalso bring potential dangers to systems normal operation such as aerospace aviation, powertransmission, network communication, even can cause serious economic losses. Therefore,studying the ice adhesion characteristics of material surface, especially researching iceadhesion strength change rules of different surfaces, it has important significance to obstructicing, deicing and ensure safe and efficient operation of system.Taking the method of chemical etching using NaOH solution and surface modificationusing fluorine silane to prepare test samples with different surface properties, and havingexperimental characterization on their surface properties. Putting samples under lowtemperature condition to make freezing, using the built experimental apparatus of iceadhesion strength. Measuring the effect wet ability, surface microstructure and surface energyon surface ice adhesion strength of samples, and then exploring the surface can obstruct icingand reduce adhesion, thereby to guide the optimization design of low adhesion surfacestructure.Results show that ice adhesion strength of hydrophobic surfaces is less than hydrophilicsurfaces. S8#has maximal surface contact angle(154.9°) and minimum ice adhesion strength,only22.8kPa，which is got by chemical etching8min and fluorine silane modifying24h.Compared with the bare aluminum specimens, the ice adhesion reduction factor reached3.3.Further study shows that the relationship of ice adhesion strength and contact angle is notclear, it can’t use the surface contact angle to evaluate material surface properties of obstructicing and reduce adhesion.Through analyzing the relationship between ice adhesion strength and surface roughness,fractal dimension, found that hydrophilic surfaces ice adhesion strength increased with theincrease of roughness, hydrophobic surface ice adhesion strength decreases with the increase of roughness, this is mainly due to the different effect of surface roughness on wet ability.Further analysis showed there exist the following relationship between surface roughness andits ice adhesion strength, that is y1.0726x+52.509(hydrophilic), y-0.6736x+74.483(hydrophobic). Moreover，hydrophilic surfaces ice adhesion strength decreases with theincrease of fractal dimension, hydrophobic surface ice adhesion strength increased with theincrease of fractal dimension. The corresponding linear relations are: y-146.6x+493.5(hydrophilic), y=95.45x-209.9(hydrophobic).Surface energy can also has a great influence on ice adhesion strength. When surfaceenergy of samples is smaller, ice adhesion strength is also smaller; Surface energy is larger,ice adhesion strength is also larger. Analysis from the classical heterogeneous nucleationtheory, aluminum samples after modified by fluoride silane have low surface energy, thecritical crystal nucleus radius will be bigger, it’s harder to form ice crystal, thereby causedsmaller ice adhesion strength.