The Effect of Co on HDDR Phenomena in the Sm3(Fe, V)29 Compound

The addition of cobalt was found to increase the disproportionation temperature and decrease the recombination temperature of Sm3(Fe, V)29. TEM of disproportionated samples showed rod-like SmH2 phase ≈5 nm in diameter in anαFe(Co, V) matrix, and features of about 50 to 100 nm in size were found in a 30% Co sample recombined at 630°C for 1 hour. In addition to αFe(Co, V) and TbCu7 type phases, XRD also showed the presence of an unidentified phase that forms at high Co contents and low recombination treatment temperatures, which appeared to have an adverse effect on the magnetic properties, after nitriding.