Journal of the American Ceramic Society, Vol.102, No.12, 7564-7574, 2019
Researches on the pyrolyzing strength of gelcasting Al2O3-based ceramic molds for double-wall blade
An approach using AM-MBAM and Na-alginate double-gel was proposed to avoid the cracking of ceramic impingement holes cores (CIHCs) during pyrolysis processing. Finite element analysis (FEA) was used to calculate the thermal stress that caused CIHCs cracking. For ceramic slurry with a double-gel containing various proportions of alginate, the addition of 15.0 wt.% alginate was the most beneficial for the rheological and mechanical properties of Al2O3-based ceramic obtained by aqueous gelcasting based on the double-gel network had a dramatically pyrolyzing strength of 14.1 MPa, which was 72.0 % higher than that of the ceramics based on the single AM-MBAM system. The double-gel network was responsible for the improved strength. By comparing the thermal stress with pyrolyzing strength, it was predicted that the available diameter of CIHCs was greater than 0.7 mm. Finally, CIHCs with a minimum diameter of 0.7 mm were successfully fabricated, consistent with the FEA prediction.