激光对鳞片石墨改性酚醛树脂涂层的损伤机理

Laser damage mechanism of flake graphite modified phenolic resin coating

为了分析高能激光对鳞片石墨改性酚醛树脂涂层的损伤机理,本文采用激光辐照方法研究激光对该涂层的损伤过程。首先,制备出纯酚醛树脂涂层和鳞片石墨改性酚醛树脂涂层,使用不同的激光参数进行激光辐照实验,根据损伤区域形貌和损伤面积分析鳞片石墨的对涂层的改性作用,分析损伤区域微观形貌和内部残炭的石墨化程度,通过对损伤中心进行三维成像来分析烧蚀凹坑的尺寸与烧蚀深度。最后,根据不同颜基比涂层在激光辐照过程中损伤区域的面积和显微形貌,分析了颜基比对激光损伤涂层过程的影响。分析结果表明:酚醛树脂经激光辐照后会裂解生成石墨化程度不同的残炭,经鳞片石墨添加改性后,损伤区域的面积相比于纯酚醛树脂涂层最大可增加35 mm2。由此可知鳞片石墨的添加改性增强了涂层的横向散热能力,但过高的颜基比会使具有粘附作用的残炭生成量减少,进而导致鳞片石墨脱落明显,涂层损伤严重。

In order to analyze the laser damage mechanism of flake graphite modified phenolic resin coating,we use laser irradiation method to study the process of irradiation. First,we prepare phenolic resin coatings and flake graphite modified phenolic resin coatings and irradiate these coatings with different laser parameters.According to the morphologies and area of the damage areas,we get the information about the modification effect of flake graphite. After that,the degree of graphitization and the micro-morphologies of the residual char are tested to analyze the structure of damage area. Besides,ablation depth and ablation area are measured through the three-dimensional micro shape. Finally,we analyze the effect of binder ratios by comparing the micro-morphologies and area of different coatings＇ damage areas. Experimental results indicate that phenolic resin will decompose into residual char with different degrees of graphitization when it is irradiated by laser.With the modification of flake graphite,the damage area of the coating increases by 35 mm^2. Thus,flake graphite improves the horizontal heat dissipation ability of the coating. However,a large binder ratio will re-duce the residual char,which plays a part in sticking flake graphite on the coating. The coating will be damaged seriously because of the loss of flake graphite.