THERMAL-DECOMPOSITION OF ZIRCONIUM HYDROXIDE

The thermal decomposition of zirconium hydroxides prepared from aqueous ammonium hydroxide solutions on the addition of potassium fluorozirconate, K2ZrF6, under various conditions has been examined by thermogravimetry, differential thermal analysis, X-ray diffraction study and infrared spectrophotometry. As a result, it is found that the thermal decomposition of zirconium hydroxide proceeds according to {A figure is presented} In this process, the transformation of amorphous ZrO2 to either the metastable tetragonal or monoclinic form depends on the composition of the original starting material as an hydrated oxyhydroxide, ZrO2-x (OH)2x · y H2O where x ≤ 2 and y {reversed tilde equals} 1. © 1979.