Measurement of Modulus in Ceramic Gelcasting Process by Vane Geometry

A four-blade geometry test fixture was used to capture the evolution moduli of alumina suspensions in gelcasting process in oscillatory measurement. The vane geometry was treated as a couette while the test material moving with the blade formed cylinder-like shearing surface. The diameter of the cylinder was defined as effective diameter of vane and calibrated by comparing the complex modulus G* with data from parallel plate in measuring polyacrylamide solution. Test results show that the effective diameter of the shearing cylinder is smaller than the diameter of the blades . This method provides an convenient way to measure the sol-gel transition in gelcasting process.