Synthesis and characterization of Ni–Co needle-like alloys in water-in-oil microemulsion

Ni–Co alloy powders of different compositions were synthesized directly from metal chloride in the cationic W/O microemulsion of water/butanol/cetyltrimethyl bromide (CTAB)/n-octane. X-ray diffraction (XRD) data showed that Ni and Co atoms were well alloyed. Transmission electron microscope (TEM) characterizations indicated the presence of nanorods in the alloys. The results of magnetic property measurements exhibited that the coercivity of these alloys improved with the proportion of Co increasing. The possible formation mechanism of alloys is discussed.