Thermal and mechanical performance of cork insulated aluminum honeycomb panels exposed to corrosive environment

Aluminum (Al)-honeycomb panels covered with cork agglomerate were tested for evaluating their thermal and mechanical performance when exposed to an accelerated corrosive environment. The bonding and adhesion between the aluminum face sheet and cork was good, as found from the optical microscopic images. Thermal conductivity of the cork, the Al-honeycomb panel, and the combined cork-Al-honeycomb panel (“sandwich” panel) were measured. The thermal conductivity results showed that the cork provided very good insulation to the Al-honeycomb panel. The thermal conductivities of no-corroded and corroded samples of the “sandwich” panel were measured and compared. Moreover, the mechanical performance of the “sandwich” panel was evaluated in terms of flexural stiffness, total energy absorption, peak load, and load efficiency through 3-points bending tests on no-corroded and corroded samples at three different time frames (1 month, 2 months, and 3 months). Using the cork as a cover material, the bending stiffness and total energy absorption remained the same for all corrosion time periods compared to the no-corroded samples; the peak load, and load efficiency values were slightly changed randomly. Cork protected the Al-honeycomb panels from degradation of its mechanical properties by the corrosive environment. Cork is a lightweight and bio-based material that can be used a cover material for the Al-honeycomb panel especially in marine or offshore applications where Al-honeycomb suffers the harsh environment of salty water and temperature.