The thermal decomposition of zirconium oxyhydroxide

The thermal decomposition of zirconium oxyhydroxides prepared by the mixture of aqueous zirconium oxychloride solutions and aqueous solutions of sodium hydroxide or ammonium hydroxide under various conditions has been examined by thermogravimetry, differential thermal analysis, X-ray diffraction study and infrared spectrophotometry. As a result, it is seen that the thermal decomposition of zirconium oxyhydroxide, in which the composition is ZrO2-x(OH)(2x).yH(2)O where xless than or equal to2 and 1less than or equal toy2, proceeds according to the following process: ZrO2-x(OH)(2x.)yH(2)O --> amorphous ZrO2 --> metastable tetragonal ZrO2 --> monoclinic ZrO2.