Preparation and Optimization Green Gel Casting Technique for Manufacturing Near-Net-Shape Ceramics Using Genetic Algorithm

Gel casting technique is a promising technology that has ability to produce near-net shape ceramics via using toxic and non-ecofriendly agents. The current work aim to develop green gel casting technique using water as a solvent, agar as a gelling agent, and the microwave thermal treatment instead of cross linker. 8mo l% Yttria stabilized zirconia was selected as a case study to produce near-net shape ceramics. The experimental work involved the preparation of Yttria stabilized zirconia nanoparticles via chemical precipitation method. The effect study of agar ratio, Yttria stabilized zirconia solid loading percent on the physical, mechanical, surface properties of the prepared ceramics and selecting of suitable casting conditions. The study has been found that the microwave thermal treatment develops thermally activated cross linking in the agar aqueous solution leading to higher glass transition temperature for agar. The green combination (agar aqueous solution and microwave treatment) can be used as alternative to (monomer, solvent, cross linker) Companion. Also, using the ultrasonic treatment can effectively eliminate needs for dispersants, also the vacuum de-airing treatment. Yttria stabilized zirconia ceramic with high dimensional accuracy, low surface roughness (Ra=2. 81 nm) can be obtained using an agar ratio of (0.4%) and solid loading of (65%). The sample can be moulded with complex shape and the green gel, also the pre-sintered body is machineable. The sintered samples have a porosity of (31%) and compressive strength of (234MPa). Regression analysis and genetic algorithm are showed that the obtained microhardness, compressive strength, and surface roughness are predictable.