Sharif Digital Repository

Zirconia Toughened Alumina (ZTA) is a well-known ceramic matrix composite due to its high fracture toughness and good mechanical properties. Addition of spinel (MgAl2O4) to ZTA inhibits alumina grain growth and produces phase boundaries with low strength. This phenomenon leads to formation of a ceramic matrix composite with special mechanical properties such as high temperature super plastic deformation. However, the room temperature mechanical properties of alumina-spinel-zirconia (AMZ) composite such as fracture toughness were rarely investigated by researchers. In this research the AMZ nanocomposite powders were synthesized via solution combustion method. The dense AMZ composite samples... 

In this process transparent polycrystalline alumina ceramic was provided by submicron alumina gel casting and spark plasma sintering. The monomer system in this process including met acrylamide and methylene bis acrylamide was chosen as a monomer and cross linker. These two agents comprise 5%wt of the precursor with the ratio of 3 to 1 respectively. With the optimization of Dolapix CE64 as a dispersant and providing the suspension with 76%wt, a greenware with the density of 56.3% wt was obtained. Differential thermal analysis of green body showed that the existing monomers are removed by the time the body reaches 550°C. In order to access high real in-line transmittance, the microstructure... 

Gelcasting is a new ceramic forming technique getting worldwide attention. The process is based on casting of slurry; containing powder, water and water-soluble organic monomers. The premix solution was prepared using Acrylamide as a monomer and Methylene bisacrylamide as a crosslinker with AM:MBAM ratio of 25:1, and Poly Acrylic Acid Sodium as a dispersant (1 wt% based on ceramic powders weight). A series of Al2O3/ZrO2 ceramic nanocomposites with 15, 17.5 and 20 wt% content of ZrO2 and 40, 43, 45, 47, 50, 53 and 55 vol.% of solid loading were fabricated by gelcasting. After casting the mixture, the monomer was polymerized to form gel parts. Drying, burning out and sintering completed the...