Airborne equipment salt spray test

Salt spray is one of the distinctive features of the oceanic atmosphere. Salt spray is easily adsorbed on the surface of objects to form a moisture film or water film. Its impact on airborne equipment mainly includes three aspects: electrochemical corrosion, accelerated stress corrosion and the corrosive effect of acid/alkali solutions formed after salt is ionized in water.
The salt spray environment is particularly harmful to airborne equipment and is one of the main reasons for frequent airborne equipment failures. According to field surveys (coastal airports), it was found that the metals in plugs, instruments, motors, and electronic products on aircraft are sometimes almost completely corroded; in addition, salt solutions can also reduce the insulation resistance of insulating materials and increase the voltage drop of electrical contact components.
For example, the engine ignition system may not fire due to the accumulation of salt particles. In coastal areas, it is found that the hairspring of the instrument is corroded, which affects the torque; the shaft tip and bearing are corroded, and the friction torque is increased, leading to corrosion and breakage; the paint layer is corroded and falls off with a wipe; the deposition of salt particles can also cause the moving parts of the instrument to be blocked and stuck.
It can be seen that under the action of salt spray environment, different aviation products have different corrosion damage characteristics. The purpose of the salt spray test for aircraft airborne equipment is to determine the effects of long-term exposure of airborne equipment to the salt spray atmosphere or the effects of the salt spray environment during normal use.
Zhongke Testing Reliability Experiment Center has the environmental testing capabilities for various aircraft airborne equipment, and provides professional environmental testing services such as waterproof testing, sand and dust testing, mold testing, and salt spray testing for aircraft airborne equipment.

Category S: Equipment installed on parts of the aircraft that are affected by salt spray atmosphere during normal use. This type of equipment is subject to salt spray testing.
Category T: Equipment installed in locations that can be affected by harsh salt spray atmosphere, such as equipment directly exposed to unfiltered outside air on aircraft parked or used at the seaside, is classified as Category T and is subject to harsh salt spray tests.

The qualification criteria for the appearance inspection of airborne equipment salt spray test are as follows:
a) The component metal does not darken or turn black;
b) No corrosion at metal joints;
c) The corrosion area of the metal protective layer accounts for less than 30% of the total area of the metal protective layer;
d) The paint layer, except for local edges, has no bubbles, wrinkles, cracks or peeling, and the base metal does not show corrosion;
e) Non-metallic materials have no obvious whitening, swelling, blistering, wrinkles, cracks, pits, etc.

HB 6167.12-2014 Environmental conditions and test methods for airborne equipment of civil aircraft Part 12: Salt spray test
HB 6167.1-2014 Environmental conditions and test methods for airborne equipment of civil aircraft Part 1: General provisions
GB/T 4937.13-2018 Semiconductor devices Mechanical and climatic test methods Part 13: Salt spray
GB/T 2423.17-2008 Environmental testing of electrical and electronic products Part 2: Test method Test Ka: Salt spray
GB/T 12085.4-2022 Optics and photonics Environmental test methods Part 4: Salt spray