Sintering of Thoria Powders—Part IV Development of Crystallinity in Thoria Powders During Heating and its Influence on their Sintering Behaviour

Abstract

Thoria powders of different origins and thermal history have been shown to have different sintering characteristics. The difference in the sintering behaviour could not be completely accounted for by the physical characteristics of the powder.

The development of “crystallinity” with rise in temperature was studied in case of thoria powders prepared at 600°C from oxalate, carbonate and tannate, and those derived from the compound in situ, using a high temperature X-ray camera. Marked differences in “crystallinity” were noticed for powders of different origins and for those of the same origin but subjected to different calcination treatments. The shapes of the particles of different origins and calcination treatments were studied by electron microscopy. An attempt has been made to explain differences in the sintering behaviour of thoria, of different origins and thermal history on the basis of the “crystallinity” of the powders.