Preparation, microstructure and properties of yttrium aluminum garnet fibers prepared by sol-gel method

Yttrium aluminum garnet (YAG) fiber was prepared by sol-gel method using water as the solvent. The spinnable YAG sol was synthesized using Al powder, Y(CH3COOH)3·4H2O and HCl as precursors, polyethylene oxide as viscosity adjusting agent. Gel fibers with diameter of 5-10 μm were prepared from the YAG sol by using centrifugal spinning technique. YAG crystalline fibers were obtained by drying gel fibers and heat-treating at selected temperature. TG/DTA analysis showed an exotherm at 906 °C attributed to formation of YAG phase and weight loss of 45% at 1000 °C. XRD and FT-IR analysis showed that phase-pure YAG can be formed at 900 °C, and no other intermediate was observed. The grain size of YAG fibers increased from 25 to 220 nm and tensile strength decreased rapidly from 970 to 380 MPa when the sintering temperature increased from 900 to 1550 °C.