The System La ₂ O ₃ — TiO ₅ ; Phase Equilibria and Electrical Properties

Abstract

Phase relations at liquidus temperatures in the system La 2 O 3 ‐TiO 2 were studied in air. The existence of two previously unreported compounds, La 2 O 3 . TiO 2 and 2La 2 O 3 ‐TiO 2 , is postulated on the basis of X‐ray and microscopic examination of crystalline samples, and in the case of La 2 O 3 .‐TiO 2 , on a maximum in the liquidus curve at that composition. Quenched liquids of the primary‐phase field of rutile were found to be semiconducting. This property was related to oxygen loss from both liquid and crystalline phases and is discussed in the light of weight loss experiments, microscopic examination of quenched samples, and information obtained from the literature. Dielectric constant and loss factor of the compounds La 2 O 3 ‐TiO 2 , La 2 O 3 ‐2TiO 2 , and 2La 2 O 3 ‐9TiO 2 are reported at 1 Mc over the temperature range 25° to 500°C.