Removal of Double Oxide Film Defects by Ceramic Foam Filters

In this study, Weibull statistical and statistical image analyses of porosity were employed to determine the efficiency of ceramic foam filters for the removal of double oxide film (bifilm) defects from a pure Al melt. Using these efficiencies and the branch filter model, the average size of the inclusions present in the liquid was estimated, and assuming that most of the inclusions in the melt are in the form of double oxide films, the possible dimensions for these defects were calculated. The results showed that the foam filters can remove oxide defects from the melt and that the efficiency of this filtration depends on the pore size of the filter. The average dimension of the oxide film defects was calculated to be 13.8x13.8 mu m with a maximum thickness of 1 mu m, if they remained non-convoluted in the metal flow. If they became convoluted because of the turbulence of the liquid flow, then the dimensions of the flat defect before it became curled up in the flow were calculated to be between 37x37x1 and 370x370x0.01 mu m.