PREPARATION AND GRAIN-GROWTH OF MAGNESIA-ALUMINA SPINEL/YTTRIUM ALUMINUM GARNET COMPOSITE FIBERS

摘要

Magnesia-alumina spinel/yttrium aluminum garnet composite fibers were prepared by sol-gel method. The spinnability of precursor sol remarkably depended on the addition amount of polyvinylpyrrolidone. Long gel fibers, with 80 cm in length, were obtained by adding 28 wt. % spinning additive. The phases of composite fibers were magnesia-alumina spinel and yttrium aluminum garnet after heating at 1400 degrees C for 2 h. The Mg iron can hinder the yttrium aluminum garnet grain growth by solute drag and grain boundary pinning. The grain growth exponent was about 3.7 at 1600 degrees C.