Gelcasting of Yb3Al5O12 using a nontoxic water-soluble copolymer as both dispersant and gelling agent

In this paper, a nontoxic water-based copolymer of isobutylene and maleic anhydride (Isobam) is used for gelcasting of Yb3Al5O12, which acts as both dispersant and gelling agent. The advantages of this gelcasting system are that only one additive is used, and it is easy to fully remove. Both the rheological property and gelling behavior of the ceramic slurries are investigated, and the mechanism of rheological property is disclosed. The ceramic slurry with 50 vol% solid loading and 0.4 wt% Isobam is optimized for gelcasting. Using this new and simple system, the gelcasting processing is controllable by changing the temperature. In addition, the dried green body has high strength that it can be machined without failure. The microstructures of the green and sintered bodies are homogeneous, and large defects are not observed. The bulk Yb3Al5O12 sample sintered at 1600 °C reaches a relative density of 94% with a flexural strength of 159±7 MPa, which is comparable to that of the hot-pressed Yb3Al5O12 material.