Abstract
Preparation and magnetic properties were investigated on the Co doped α′′-Fe16N2 obtained in low temperature nitridation of bcc Fe1−xCox alloys to change its magnetic coercivity. The alloys were prepared by the reduction of (Fe1−xCox)3O4 obtained by hydrolysis of iron and cobalt acetylacetonate mixture in benzyl alcohol. Fine powder of the pure spinel-type (Fe1−xCox)3O4 was obtained in x = 0–0.05. The oxides were reduced to bcc Fe1−xCox alloy at 400°C in H2 gas and then nitrided at 150°C for 5 or 8 h under NH3 gas flow. XRD and X-ray absorption spectroscopy suggested the nominal “α′′-(Fe1−xCox)16N2”, similar to “α′′-Fe16N2” was obtained as a mixture with the residual bcc Fe1−xCox alloy at x = 0.03 as in the case of the nitrided product without cobalt. The present nitrided product exhibited a larger magnetization of 217 Am2 kg−1 and a smaller magnetic coercivity of 30 mT at x = 0.03 than those for the present products without the Co doping.
