In this work, a combined process, called centrifugal gel casting (CGC), was proposed for the fabrication of homogenous and reliable monolithic and composite ceramics starting from submicrometer-sized powders. This method exploits the advantages of both conventional gel casting (GC) and centrifugal slip casting (CSC), while overcoming the limitations associated with the two methods. Via this process, a relatively low centrifugal force is applied to form a highly concentrated slurry in the mold cavity, which is then followed by in situ polymerization of slurry during gelation. In this work, concentrated alumina slurries with different solid contents from 45 to 65 vol% were consolidated by the three forming methods mentioned above. Various properties of green and fired products were measured and compared. Shorter processing time, lower centrifugal force, higher green strength, and minimal segregation are observed to be the characteristics of CGC in comparison with CSC. In situ elimination of bubbles with no need for degassing and the ability to remove heterogeneities, on top of high reliability and the potential to process higher viscosity slurries, are the main advantages of this method over the conventional GC.
Materials Science and Engineering Department, School of Engineering, Shiraz University, Shiraz 7134851154, Iran 2:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore