The interaction of commercially available, iron‐based magnetic particles with certain particulate media formulation components has been investigated using the technique of flow microcalorimetry. The heat of wetting of these particles by solvents has been found to be a function of the solvent dipole moment and particle coercivity and surface area. Di(2‐ethyl hexyl) phosphoric acid, a model dispersant, appears to interact chemically with a particle of high coercivity. Solvent basicity influences the heat and extent of interaction of the dispersant.<lz> <lz> <lz> <lz> <lz> <lz> <lz>