Ceramic Coatings and Glass Additives for Improved SiC-Based Filters for Molten Iron Filtration Michael C. Tucker* Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 Jay Tu Foseco – Foundry Division of Vesuvius, Cleveland, Ohio 44142 Reticulated silicon carbide (SiC) ceramic filters are prepared with modified coatings in an attempt to improve mechani- cal properties of the sintered filter. Two classes of coatings are used: mixtures of non-SiC ceramic and sintering aid and mix- tures of SiC and glass. Various candidate ceramics, sintering aids, and glasses are screened. The most promising coatings are determined to be silica with 5 wt% bismuth oxide and SiC with  10 wt% Spruce Pine Batch glass. Filters with these coat- ings are prepared and subjected to mechanical abuse. Both coatings improve the ruggedness of the filter relative to the stan- dard uncoated SiC type. Filters with <10 wt% glass additive were subjected to molten metal impingement and filtration of liquid gray iron at 1510°C. Those with 5 wt% glass or more softened during filtration. Those with 2.5 wt% glass or less survived without failure. Introduction Reticulated ceramic foam filters are widely used in the foundry industry, because of their high permeability, excellent filtration efficiency, and relatively homoge- neous 3D network pore structure giving rise to deep-bed filtration. These filters are typically prepared by the rep- lica process. 1 A polymer foam template is impregnated with green ceramic slurry by coating it in a ceramic slurry bath, pressing it to fill the entire template, and then passing it through rollers to remove excess slurry. An additional outer layer may then be sprayed onto the *mctucker@lbl.gov © 2012 The American Ceramic Society Int. J. Appl. Ceram. Technol., 1–7 (2012) DOI:10.1111/j.1744-7402.2012.02850.x