Permanent magnets (PM) with rear-earth (RE) elements, such as dysprosium (Dy) and neodymium (Nd), have been widely used in motors and generators for hybrid electronic vehicles and wind turbines.[1] Concern over supply and price of the RE alloys has stimulated the search for alternative PMs.[1,2] One of the attractive non-RE PMs is alnico, a family of magnetic alloys composed primarily of Al, Ni, Co and Fe, with excellent magnetic stability at high temperature. The magnetic properties of alnico alloys are closely related to the control of the spinodal decomposition (SD) into an FeCo-rich (α1 phase) hard magnetic phase and a non-magnetic NiAlrich phase (α2 phase). Improving alnico will require subtle changes in chemistry and processing to reduce the diameter of the magnetic phase while maintaining its volume fraction. Alnico 9 is the current available commercial alnico alloy with the highest energy product (BH)max, which is both grain aligned and spinodally decomposed with an applied magnetic field.[1] Needed improvements can only be achieved through a better understanding of nanostructuring during SD. This study focuses on structural characterization of alnico 9 alloy from Arnold Magnetic Technologies. Atom-probe tomography (APT) and a combination of TEM techniques, including diffraction contrast TEM, high resolution transmission electron microscopy (HREM), high-angle annular-dark-field (HAADF) scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy, and Lorentz microscopy, were used.