脉冲激光改性碳纤维复合材料及其金属化研究

Pulse Laser Modification and Surface Metallization of Carbon Fiber Reinforced Plastic

目的选择性地实现碳纤维复合材料(Carbon fiber reinforced plastic,CFRP)表面良好的导电性,满足它在共形天线上的应用。方法采用波长为1064 nm的纳秒脉冲激光器对惰性极高的CFRP表面进行表面改性处理,并结合化学镀铜技术,制备激光改性碳纤维复合材料表面金属层。利用扫描电镜、X射线光电子能谱仪对改性后的材料表面进行表征,利用焊点拉脱方法表征金属层结合力。结果研究表明,激光能量密度越高,则CFRP基材表面树脂被去除得越多;激光搭接率越大,则碳纤维束表面越粗糙;在适当的激光能量密度(60 J/cm^(2))和横/纵向搭接率(50%)下,会产生大量的极性化学基团。当激光能量密度为10~100 J/cm^(2)、激光搭接率为0%时,CFRP表面镀铜层的结合强度为0.57~3.16 MPa,且激光能量密度与镀层结合强度呈正相关。当激光能量密度为60 J/cm^(2)、激光搭接率为−100%~90%时,CFRP表面镀铜层的结合强度为0.19~3.24 MPa,且激光搭接率与镀层结合强度呈正相关。结论脉冲红外纳秒激光在一定能量密度和搭接率的条件下,可改变碳纤维表面形貌、化学成分,实现金属层的制备。

In order to selectively achieve good surface conductivity of carbon fiber reinforced plastic(CFRP)and apply it to conformal antennas,the work aims to adopt a nanosecond pulse laser with a wavelength of 1064 nm to modify the surface of CFRP with high inertia.With chemical copper plating technology,a metal layer was prepared on the CFRP.The surface of the modified material was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy,and the bonding force of the metal layer was characterized by the method of Solder Joint Pull-off.The higher the laser energy density,the more resin was removed from the surface of CFRP substrate.The higher the laser overlap rate,the rougher the surface of the carbon fiber bundle.At appropriate laser energy density(60 J/cm^(2))and transverse/longitudinal overlap ratio(50%),a large number of polar chemical groups were added.Through chemical copper plating,it could achieve the preparation of metal layers.Carbon fiber/cyanate ester composite material was used as the substrate in the antenna field,and the surface of carbon fiber composite material was modified by infrared nanosecond pulse laser.The laser power was set at 5%to 100%,and the corresponding laser energy density(Q)was 6 J/cm^(2)to 120 J/cm^(2).The laser transverse overlap rate(Oh)and longitudinal overlap rate(Ov)were set to−100%-90%,respectively.When the laser energy density was≥60 J/cm^(2),the resin on the surface of the CFRP substrate was almost completely removed,completely exposing the carbon fiber bundle.With the further increase of laser energy density,fracture phenomena of some carbon fiber bundles were observed on the surface of the substrate.The higher the laser overlap rate,the rougher the surface of the carbon fiber bundle.When the transverse overlap rate was≥50%,or the longitudinal overlap rate was≥50%,the surface of carbon fiber bundles became more obvious with fluffy flocculent micro nano structures,and the micro roughness also increased.When the laser energy density was 60 J/cm^(2)and the transverse/longitudinal overlap rate was 50%,a large number of C-C,C-H,C═O,and C═N bonds broke and reacted with nitrogen and oxygen in the air to generate C-O,O-C═O,and C-N bonds.These Chemical bond,especially the newly added O-C═O,increased the polarity of the material surface,which was conducive to improving the wettability of the substrate surface to subsequent activation solutions and chemical deposition solutions.The plating layer was prepared on the CFRP surface and the growth process of Cu element was observed during the copper plating process.The Solder Joint Pull-off method was used to characterize the bonding force of the metal layer.The result showed that when the laser energy density was 10-100 J/cm^(2)and the laser overlap rate was 0%,the bonding strength of the copper coating on the CFRP surface was 0.57-3.16 MPa,and the laser energy density was positively correlated with the bonding strength of the coating.When the laser energy density was 60 J/cm^(2)and the laser overlap rate was−100%-90%,the bonding strength of the copper coating on the CFRP surface was 0.19-3.24 MPa,and the laser overlap rate was positively correlated with the bonding strength of the coating.