Cause of Shedding of Paint Layer on Front Rocker Arm of a Launcher Device

The paint layer (include primer and finishing coat) of the front rocker arm of a certain type launch device shed after high and low temperature test. The causes of paint layer shedding were analyzed by property of painting, and thickness and adhesion force test of paint layer, and infrared spectrum and nuclear magnetic resonance analysis. The results show that there were long chain hydrocarbon organic substances that was a constituent of mineral oil on the surface of matrix of front rocker arm was the main reason that caused paint layer shedding. The organic substances reduced the adhesion between the paint layer and the matrix, and the linear expansion coefficient between the paint layer and the matrix material were different, resulting in the cracking and finally shedding of the paint layer during the high and low temperature test.