New Results of the Crystallization Behaviour of Hexagonal Barium Ferrites from a Glassy Matrix

✍ Scribed by U. Schadewald; B. Halbedel; H. Romanus; D. Hülsenberg

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 196 KB
• Volume: 37
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.200600084

✦ Synopsis

Starting from thermoanalytic measurements of amorphous material with a composition of 40 BaO -33 B 2 O 3 -27 Fe 2 O 3 (mole -%) the onset temperatures of four exothermic reaction peaks have been obtained. On the basis of this results the amorphous material was tempered under different conditions (heating rate and tempering time). The resulting reaction products were analyzed by X -ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), chemical analyses and by a vibrating sample magnetometer (VSM) to obtain information about their chemical composition, their structure and their magnetic properties.

In contrast to former studies [2,3,4] it was found, that first an iron -rich phase forms at temperatures about 520 C -560 C [5] followed by the crystallization of BaB 2 O 4 .