A novel gel-cast SiC with potential application in turbine hot section: Investigation of the rheological behavior and mechanical properties

Using a gel-cast technique, SiC bodies were fabricated and their mechanical properties were thoroughly studied. The main goal of this study is improvement of SiC green body features by the adjustment of slurry composition or processing parameters. The influences of gel-casting parameters such as the monomer acrylamide (AM) content, tetramethyl ammonium hydroxide (TMAH) content as a dispersant, the ratio of the monomer to crosslinking agent AM/MBAM content and the ammonium persulfate (APS) as an initiator on the properties of the samples were investigated. Based on the viscosity measurement and sedimentation tests, TMAH exhibited great electrosterically stability at the pH of 10-11. After the gel-cast process, the relative density of sintered body can be enhanced to 93% and its flexural strength can reach 293 MPa at the optimized gel-casting process that has an AM content 15%, a TMAH content of 0.4 wt%, an AM:MBAM ratio of 17.5:1, an APS 10% and a solid content of 50 vol%, comparable to the best results reported in the other works for SiC bodies.