Phase Identification and Temperature-Dependent Magnetization of Ti-Rich Titanomagnetite (0.5 <= x <= 1) in Different Atmospheres

Abstract

Reduced titanomagnetite solid solutions, xFe 2 TiO 4 - (1 - x)Fe 3 O 4 , with 0.5 ≤ × ≤ 1, were synthesized by sintering in 99.996% pure flowing argon. Samples showed a systematic variation in the second phase amount as a function of x. A wustite second phase primarily forms near the surface of titanomagnetite pellets. The amount of wustite decreases with increasing Ti concentration. XRD data confirms that samples with x > 0.8 have less than 1% wustite. M(T) curves were measured by vibrating sample magnetometer (VSM). A magnetization hump is observed in M(T) during heating and explained by ferrimagnetic phases formed by exsolution and precipitation processes. These phases were identified as titanomaghemite and magnetite by fitting M(T) cooling curves with a multi-phase Brillouin function.