SOL-GEL SYNTHESIS OF CRYSTALLINE ZRO2 WITH PARTIAL REPLACEMENT OF ZIRCONIUM BY AL, NB, SI AND TA .2.

A sol-gel process was used to prepare precursor materials for subsequent conversion to crystalline ZrO2 in which a portion of the zirconium was replaced by Al, Nb, Si and Ta. These materials were obtained by the sol-gel reaction system using metal-alkoxides, orthoboric acid and pyridine. The lattice parameters for the crystalline phases of the oxides obtained at 900 and 1300-degrees-C by thermal treatments are presented. The materials belonging to the tetragonal crystal system prepared at 900-degrees-C are Zr-Al-B-O, Zr-Si-B-O, Zr-Nb-B-O and Zr-Ta-B-O, whereas the Zr-B-O material is monoclinic. The Zr-Nb-B-O and Zr-Ta-B-O materials prepared at 1300-degrees-C were tetragonal, but the oxides Zr-B-O, Zr-Al-B-O and Zr-Si-B-O prepared at 1300-degrees-C are monoclinic.