Title :
The influence of ZrO2 addition on phase composition in the Nd-Dy-Fe-B system and improved corrosion resistance of the magnets
Author :
Kobe Besenicar, S. ; Holc, Janez ; Drazic, G. ; Saje, B.
Author_Institution :
Jozef Stefan Inst., Ljubljana Univ., Slovenia
fDate :
3/1/1994 12:00:00 AM
Abstract :
The positive influence of ZrO2 addition on the magnetic properties, temperature coefficients and corrosion resistance of Nd-Dy-Fe-B magnets were established. The improvements in these parameters were attributed to microstructural changes. The phase composition was analyzed using HREM, and besides the known phases, an additional Zr boride phase was found, which was identified using crystal structure analysis as a ZrB2 plate-like phase. Due to the formation of the new phase and oxidation of Nd from the Nd-rich grain boundary phase, the sensitivity of the grain boundaries is diminished to a great extent, and as a consequence the corrosion process does not proceed in the sample. It remains limited to the exposed surface, which is a worthwhile contribution to the improvement of the resistance against corrosive conditions
Keywords :
alloying additions; boron alloys; corrosion; dysprosium alloys; electron microscope examination of materials; ferromagnetic properties of substances; grain boundaries; iron alloys; neodymium alloys; oxidation; zirconium compounds; HREM; Nd-Dy-Fe-B magnets; Nd-Dy-Fe-B-ZrO2; ZrB2; ZrB2 plate-like boride phase; ZrO2; ZrO2 addition; corrosion resistance; crystal structure; grain boundary phase; magnetic properties; microstructure; oxidation; phase composition; temperature coefficients; Corrosion; Crystal microstructure; Grain boundaries; Magnetic analysis; Magnetic properties; Magnets; Oxidation; Surface resistance; Temperature; Zirconium;
Journal_Title :
Magnetics, IEEE Transactions on
