Microstructure identification of an interfacial phase in a melt-spun Hf-Ninanocrystalline alloy

A rapidly quenched nanocrystalline Hf11Ni89 alloy was prepared by means of the melt-spinning technique. The microstructure of the as-quenched ribbon s ample was characterized by means of X-ray diffraction, transmission electro n microscopy, high-resolution electron microscopy, magnetothermal analysis and magnetic property measurements. Microstructural analyses indicated only a single HfNi5 nanophase in the as-quenched sample, while the magnetic pro perty measurements revealed a second ferromagnetic or superparamagnetic pha se with a low mean 'paramagnetic' Curie temperature. This is considered to be an interfacial Ni(Hf) solid solution phase occurring at grain boundaries . The Hf concentration of the interfacial phase was estimated by means of i ts magnetic properties. The homogeneity of composition and volume fraction of the interfacial phase were studied and a discussion of their statistical correlation is presented.