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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (11): 3528-3534.doi: 10.7527/S1000-6893.2015.0336

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Coating corrosion failure analysis and influence of titanium-steel bolted lap joints

CHEN Yueliang, WANG Chenguang, ZHANG Yong, BIAN Guixue   

  1. Qingdao Branch, Naval Aeronautical Engineering Institute, Qingdao 266041, China
  • Received:2015-11-10 Revised:2015-12-11 Online:2016-11-15 Published:2015-12-28
  • Supported by:

    National Natural Science Foundation of China (51375490)

Abstract:

Coating is the main anti-corrosion system of aircraft, and local damage of coating has an impact on other complete areas. The coat failure in concealed position is difficult to be found and affects the flight safety. Corrosion experiment is performed for titanium-steel bolted lap joints with airplane service environment simulation. After selecting appropriate boundary conditions, the causes and effects of lap surface coating failure are analyzed by finite element method which is based on the mathematical model of galvanic corrosion. The results indicate that the coating failure process could be divided into three stages; the effect of galvanic corrosion causes the electric field around the lap area; the directional accelerated motion of Cl- under the potential gradient causes electroosmotic blistering of coating. With the increase of the coating failure area, the proportion of the cathode and anode area is smaller, the corrosion of the anode reduces, the position of the maximum corrosion current density changes, and the value of the corrosion current density decreases. The failure area of the coating could be predicted through calculation of electric field of the solution around the overlapping structure. It provides the technical support for the maintenance of the aircraft coating system.

Key words: lap joints, coating failure, electroosmotic blistering, galvanic corrosion, numerical calculation

CLC Number: