Investigation into thermal treansformations of yttrium carbonate tetrahydrate by derivatography

Thermograviograms are given of initial yttrium tetrahydrate-carbonate and a dehydrated sample obtained in air at a heating rate of 10 deg./min. Dehydration of the tetrahydrate completes practically at approximately 300 deg C. A low rate of loss of mass are registered in the range 300-500 deg C. It grows rapidly with an increase in temperature and attains a maximum at 600 deq C. At these temperatures an endo-effect manifests itself in thermograms which is due to decomposition. Data of the X-ray diffraction analysis of solid products obtained by decomposition of yttrium carbonate in various atmospheres indicate that slower decomposition in the helium atmosphere can be caused by retardation of crystallization of yttrium oxide