STUDY OF SOLID STATE REACTIONS IN Sm(Co, Fe, Cu, Zr)_z 2:17 ― TYPE ALLOYS BY MEANS OF IN-SITU ELECTRICAL RESISTIVITY MEASUREMENTS

摘要

In the present work, which forms part of an ongoing European research programme (HITEMAG), solid state reactions in Sm_2(Co, Fe, Cu, Zr)_(17) ― type alloys have been investigated by means of in-situ electrical resistivity measurements. Changes in the electrical resistivity of a Sm(Co_(0.74)Fe_(0.1)Cu_(0.12)Zr_(0.04))_(8.5) alloy after solid solution treatment at 1190°C and quenching to room temperature and during isothermal ageing at temperatures between 400 ― 875°C., have indicated microstructural/phase changes occuring at temperatures below those commonly used for the development of high coercivity in Sm(Co, Fe, Cu, Zr)_z type materials. Subsequent crystallographic and magnetic transition measurements have shown a degree of correlation with respect to the changes observed in the electrical resistivity during isothermal ageing.