Measurements of minor loops of SmCo5powders have revealed that wall motion is predominant in the magnetization process. A relation between the reversible susceptibility &khgr; of the minor loops and the coercivityHchas been found, showing that the coercivity of the investigated material is determined by the pinning of domain walls, rather than nucleation. The relation &khgr;Hc2=const has been found in a wide range of coercivities obtained by aging of the material. The aging process is interpreted as a decrease of the density of pinning sites, each site retaining its pinning force. Hysteresis loops measured on single particles of a few microns size confirm these interpretations and allow for a refined model of pinned‐wall coercivity of SmCo5powders.