Optical Properties of Gel Cast and Sintered Alumina Ceramics

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Ghorbani, Mohammad | 2016

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 48438 (07)
University: Sharif University of Technology
Department: Materials Science and Engineering
Advisor(s): Nemati, Ali
Abstract:
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 of polycrystalline should be controlled and all the sources of light diffraction such as impurities second phases and porosity should be avoided. The grain growth during the sintering process by doping 500 ppm/MgO in alumina suspension was controlled. The amount of in-line transmittance concerning the final sample was obtained 37%, therefore the text behind the sample was clearly seen
Keywords:
Spark Plasma Sintering ; Porosity ; Gelcasting ; Transparent Polycrystalline Alumina ; Green Density

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