纳秒激光制备钛表面纹理结构及其润湿性研究

Study on the fabrication of titanium surface texture by nanosecond laser and its wettability

激光加工技术可在材料表面形成多种纹理结构,为了研究激光加工所得不同纹理结构对材料润湿性的影响,通过纳秒激光加工技术在金属钛表面分别加工直线、网格和点阵的表面纹理结构。采用扫描电子显微镜、接触角测量仪、粗糙度分析仪和X射线光电子能谱分别对激光加工后的钛表面进行表面形貌、接触角、粗糙度与化学成分的表征与分析。结果表明:初经激光纹理加工后试样表面的粗糙度较激光加工前均显著提高,但此时3种纹理结构试样表面接触角均小于90°;随着时间的推移,被加工材料表面化学成分的改变带来了材料表面自由能的变化,进而使被加工表面接触角总体呈现上升趋势;待试样表面化学成分稳定后接触角也基本保持不变,并且对于每种纹理结构而言,其接触角随粗糙度的增加而升高。直线、网格和点阵纹理结构试样表面接触角最终可达157.2°,153.1°和134.6°,从而实现了钛表面润湿性由亲水性向疏水性的转变。

Laser processing technology can produce various types of surface textures on material.In order to investigate the effect of surface texture type processed by laser on the wettability,line,grid and spot patterns are fabricated on titanium surface based on nanosecond laser processing technology.Then surface morphology,water contact angle,roughness and chemical composition of the processed titanium surface are analyzed by scanning electron microscope,contact angle measuring device,surface analyzer and X-ray photoelectron spectroscopy,respectively.It is found that the roughness of titanium surfaces processed by nanosecond laser increases significantly compared with that of the unprocessed titanium surface,while the surface contact angles of the processed titanium surfaces are all less than 90°.As time goes on,the chemical composition variation ofablated titanium surface results in the change of material surface free energy,which leads to a general increase of the surface contact angle.Finally,the surface contact angle is almost unchanged once the chemical composition of titanium surface reaches steady state.For each type of surface texture,surface contact angle increases as the roughness rises.The surface contact angles of processed titanium surfaces with line,grid and spot patterns can be 157.2°,153.1°and 134.6°,which verifies the possibility of wettability change of titanium from hydrophilicity to hydrophobicity.