Investigation of premature blistering and delamination of coated AA5006 window frames using scanning (SEM) and transmission electron microscopy (TEM), glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy (XPS) is presented. SEM of the blisters revealed corrosion of Aluminium and accumulation of corrosion products at the interface of coating and metal. TEM and XPS analysis revealed a thin and non-homogenous hexavalent Cr conversion layer. High number density of intermetallics, and surface defects from metal forming process resulted in a defective conversion coating leading to reduced corrosion protection of aluminium in the presence of water and Cl from atmosphere.

A thermodynamics formulation for two-dimensional (2-D) diffusion in hybrid composite is discussed. The model had been transferred in a computer code and the validation is assessed here through the comparison with the analytical solution in the case where Fick's law is adequate (2-D, only 1 material) and with the experimental measurements in some simple cases (1-D, more than 1 material). An example of the use of the computer code is presented.

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Two accelerated hot-wet aging tests of glass-reinforced epoxy resin were performed at 45 and 70°C at the same level of relative humidity (RH = 84%). Mechanical and physical properties of “dry” and differently saturated composites are compared. It has been found that the higher the conditioning temperature, the higher the equilibrium moisture content. The glass transition temperature decreases from 138°C (dry) to 108 to 111°C (for both moisture saturated cases). Moreover, it has been found that moisture absorption reduces the static properties while not modifying the endurance in fatigue tests.