Mechanical properties of aluminum foams ceramic coated through plasma electrolytic oxidation

Plasma electrolytic oxidation (PEO) treatment is carried out to improve the mechanical properties of the open-cell aluminum foams. Two different pore densities of open-cell aluminum foams (20 PPI and 40 PPI) were treated in an alkaline solution with a low silicate concentration at different current densities and times. The microstructure and phase composition of samples were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. The coating thickness of the struts was increased with the increasing of treatment time. Ceramic coatings were composed of corundum, gamma alumina, and mullite phases. It was found that the compressive properties of the pore density of 20 PPI composite foams were significantly improved by using PEO treatment.