聚碳硅烷复合涂层抗激光烧蚀研究

Laser Ablation-Resistance of Polycarbosilane Composite Coatings

提出在飞行器表面涂敷经过固化的聚碳硅烷复合涂层,激光照射时聚碳硅烷吸收激光能量发生分解和相变等物理化学过程,最终形成耐高温SiC陶瓷,从而减弱或消除激光对飞行器的打击。实验以铝合金为基板,以聚碳硅烷和二乙烯基苯混合溶液为涂料,并添加了ZrO2、V2O5等高温可发生相变的陶瓷,铝合金基板涂覆后在150℃大气环境下保温6 h固化,形成黏附性好、有一定硬度的抗激光涂层,然后通过连续激光进行烧蚀验证。结果表明,基板没有烧蚀变形,聚碳硅烷涂层在激光烧蚀作用下发生分解、相变,生成了SiC陶瓷和游离C。其中添加剂ZrO2因高温相变体积缩小缓解了涂层与基板的热失配,不仅吸收激光能量,消弱了激光烧蚀,而且涂层与基板结合牢固没有脱落,对激光有良好的阻挡作用。

This thesis presented that the cured polycarbosilane composite coatings brushed onto the surface of the aluminum alloy substrate were ablated by laser. The polycarbosilane was decomposed and transformed to form heat-resistant ceramic after absorbing the laser energy, which led to weaken or eliminate laser attacking to aircrafts. In this experiment, the aluminum alloy plate was used as substrate. The coating solution was composed of polycarbosilane and divinylbenzene. The ceramic powders which could transform in high temperature, such as ZrO2 and V2O5, were added into the solution. The as-coated aluminum alloy substrates were placed in ambient atmosphere at 150℃ for 6 h to cure to form anti-laser coatings, which resulted in a good adhesiveness and rigidity. Then the coatings are ablated by continuous laser to validate the method. The results indicated that the substrates have no distortion and the polycarbosilanes coatings are decomposed and transformed to form SiC ceramic and free carbon. The phase transformation of added ZrOz occurred with volume shrinkage, so it weakened the dilatability difference between the coating and substrate. ZrOz absorbed the laser energy and weakened the laser ablation. The coating adhered on the substrate firmly and do not come off. Laser ablation is effectively resisted by the coatings.