ニオブおよびタンタル五酸化物の性状
1965 年 81 巻 920 号 p. 30-34
詳細
1965 年 81 巻 920 号 p. 30-34
Nb2O5 and Ta2O5 are both hydrated precipitates from aqueous solutions. When heated at various temperatures, however, they liberate combined water and become crystalline. Their X-ray powder diffraction data were investigated, which indicated the existence of three modifications for Nb2O5, as follows: L formbelow 780°C L+M form from 780°C to 980°C M formfrom 980°C to 1150°C M+H from from 1150°C to 1300°C H formabove 1300°C
These transformations are function of temperature and time. There are two modifications for Ta205. The structure below 1200°C is isomorphous, coinciding with the low temperature modification (L-form) of Nb205. Above 1200°C it is transformed slowly into the high temperature form.
In Nb205-Ta205 system, solid solution is formed, whose ranges were shown in the diagram.
