铝合金蒙皮激光除漆后新漆层的耐高温性能研究

Study on the high temperature resistance of new paint layers afterlaser paint removal from aluminium skins

在实际飞行环境中温度是引起漆层失效的重要因素之一,飞机在长时间服役后需去除老化漆层以便喷涂新漆层,确保飞机运行的安全性和可靠性。本文采用波长为1064 nm的平顶脉冲激光对铝合金蒙皮表面漆层进行清洗,并对铝合金蒙皮激光除漆后新漆层进行高温加速老化,模拟飞机停场时铝合金漆层系统的耐高温性。采用扫描电子显微镜、激光共聚焦显微镜、附着力测试仪以及电化学工作站,综合评价了激光除漆效果及新漆层表面形貌、漆层与铝合金的附着力、电化学阻抗特性等耐温性指标。结果表明:激光功率500 W、扫描速度4000mm/s、扫描间距0.1 mm时可将铝合金表面漆层去除且不损伤铝合金,重新喷涂后的附着力达到0级且附着力时效性能较好;150℃加速老化48 h的漆层附着力为1级,漆层表面微观形貌无明显变化、漆层光滑平整、无缺陷且低频区域电化学阻抗模值>10^(9)Ω·cm^(2)。

Temperature is one of the most important factors causing paint failure in the actual flight environment,and after a long period of service,it is necessary to remove the aging paint layer in order to paint a new one to ensure the safety and reliability of the aircraft operation.In this paper,a flat-top pulsed laser with a wavelength of 1064 nm is used to clean the paint layer on the surface of the aluminium alloy skin,and to accelerate the aging of the new paint layer after laser paint removal from the aluminium alloy skin at high temperatures to simulate the high temperature resistance of the aluminium alloy paint system when the aircraft is parked.A scanning electron microscope,a laser confocal microscope,an adhesion tester and an electrochemical workstation are used to evaluate the effect of laser paint removal and the surface shape of the new paint layer,the adhesion of the paint layer to the aluminium alloy,the electrochemical impedance characteristics and other temperature resistance indicators.The results show that the laser power of 500 W,scanning speed of 4000 mm/s,scanning interval of 0.1 mm can remove the paint layer on the surface of aluminium alloy without damaging the aluminium alloy,and the adhesion after repainting reaches grade 0 and has good adhesion time performance;the adhesion of the paint layer after accelerated aging at 150°C for 48 h is grade 1,and there is no obvious change in the microscopic morphology of the paint layer surface,the paint layer is smooth and flat,without defects and low frequency modulus value>109Ω·cm^(2).