Accelerated Corrosion Environmental Spectrums for Testing Surface Coatings of Critical Areas of Flight Aircraft Structures

An accelerated corrosion environmental spectrum was introduced to test the surface coatings of the critical areas of flight aircraft structures. The spectrum is composed of hot-humid environment、ultraviolet radiation、thermal impingement、low temperature fatigue and salt spray. One single cycle of the spectrum was supposed to be equal to one-year experience in ground environment. In combination with the actual environment of marine and hot-humid area in China, concrete conditions for hot-humid and thermal impingement tests were developed. The proportions of neutral and acidic salt sprays, the ultraviolet radiation time and the method of determining low temperature fatigue stress levels were established. The programming of the accelerated environmental spectrum was conducted by combining the corrosion critical areas of  flight aircraft. The equivalent relations that single cycle represents one year in marine and hot-humid areas were verified by comparing the corrosion degrees between the accelerated corrosion environmental spectrum and ground environmental spectrum.