电火花加工制备铜基微纳层次结构及其疏水性能

Fabrication of hierarchical micro/nano structure surface on copper by EDM and its hydrophobicity

利用电火花成型加工技术制备铜基微纳层次结构疏水表面,该微纳层次结构主要由微纳孔洞、熔珠、重熔区和热应力裂纹等微观结构组成,考察了不同脉宽参数对微纳层次结构疏水性的影响。结果表明:随着脉宽的增大,微纳层次结构中微纳孔洞数量增加,各种微观结构的层次分布程度增强,增大“气垫”效应区域,可存储更多的空气在其表面,提高了微纳层次结构的疏水性。固-液界面所占面积分数(f sl)减小,水滴和表面孔洞中的“气垫”接触面积增大,使得微纳层次结构对水滴的物理吸附作用减弱。微纳层次结构接触角可增至(144.7±2.1)°,接触角滞后性范围为(8.46±3.3)°^(14.10±1.2)°。

The hierarchical micro-nano structure surface on copper was fabricated by electrical discharge machining(EDM).The hydrophobic property was increased due to the hierarchical micro/nano structure(HMNS),which consisted of the micro/nano scale holes,molten balls,recast regions and the micro thermal cracks.The effects of the pulse width on the hydrophobicity of HMNS were investigated.The results indicate that with the increase of the pulse width,the quantity of the micro-nano scale holes increases.The distribution of other hierarchical micro structures is more homogeneous.The effective area of“air cushion”increases,which can trap more air in the HMNS.And the hydrophobicity of HMNS also increases.The proportion of the solid-liquid interface area(f sl)reduces.The contact area between the water droplet and“air cushion”in the HMNS increases.Therefore,the effect of the physical adsorption for the HMNS on the water droplet is weakened.The contact angles of the HMNSs can be increased up to(144.7±2.1)°,and the range of contact angle hysteresis is(8.46±3.3)°-(14.10±1.2)°.