Study Of Accelerated Corrosin Methods Of Graphite Epoxy Composite Material Under The Marine Environment

Graphite Epoxy Composite Material has been widely used in aircraft because of its excellent mechanical properties and designability. Its corrosion in the marine environment has attracted more and more attention. Marine atmospheric corrosion is a more serious problem of the natural environment corrosion. Marine atmospheric environment would lead matrix, fiber or fiber-matrix to change or destroy, thereby to affect the performance of graphite epoxy composite material.This paper uses the immersion method to study the moisture absorption characteristics of carbon fiber epoxy composite materials in different media, and to better understand the absorption behavior of composite materials and aging mechanism in different media. At the same time according to the requirements of GIB150《Laboratory equipment test methods for military materiel》, using the test conditions of damp heat test and salt spray test to simulate marine atmosphere for accelerated aging test, and to evaluate the durability of carbon fiber epoxy composite materials in the marine environment , aging behavior after the aging test was studied by changes in mass gain, mechanical properties and surface morphology, so that to provide a theoretical basis for enhancing the environmental adaptability of military equipment.The immersion test show that: in distilled water and 5% NaCl solution, the absorption characteristics of graphite epoxy composite material was obeyed the Fick’s second law. In 5% H2SO4 solution, at the immersion test early stage, the absorption behavior of composite material was similar to the Fick diffusion, but the absorption rate of post-immersion test was declined. In 5% NaOH solution, the moisture content of composite material was increased linearly at first, and the later was declined a little, and finally was increased with the prolongation of immersion time. In addition, the increase of environmental temperature would lead to a quicker diffusion of water in graphite epoxy composite material and a higher equilibrium moisture content Damp heat test show that: the mass gain increase, the mechanical properties decrease and carbon fiber and epoxy resin adhesive is getting worse with the aging time. Composite in hot and humid environment, the weight gain is mainly due to its moisture absorption, mechanical properties decrease quickly in the initial period of moisture absorption, after 20 days of heat aging, interlaminar shearing strength and bending strength decreased to 58.3% and 53.8% respectively.Salt spray test show that: carbon fiber epoxy composite materials in the salt spray environment, the major weight gain caused by the absorption of water, the second reason is the deposition of salt spray on the material surface. The mass gain increase, the mechanical properties decrease and carbon fiber and epoxy resin adhesive is getting worse with the salt fog aging time, after 10 days of salt fog aging, interlaminar shearing strength and bending strength decreased to 89.7% and 90.2% respectively.