1. Protective atmospheres employed in sintering have an appreciable effect on the physicomechanical properties, composition, and structure of powder metallurgical antifriction materials. 2. The sintering of iron-graphite materials in all protective atmospheres (with dew points ranging from −28 to −40°C) is accompanied by their decarburization, although in converted natural gas carburization of porous iron is observed. 3. After sintering in all protective atmospheres, ZhGrl iron-graphite material has higher mechanical properties and a more stable composition than all the other materials investigated. 4. The highest tensile strength and the maximum ductility are exhibited by materials sintered in a vacuum; the highest hardness is shown by materials sintered in hydrogen, dissociated ammonia, and converted natural gas; and a lower hardness is shown by those sintered in a vacuum. The highest compressive strength is imparted to materials by sintering in hydrogen and dissociated ammonia. The variation of the mechanical properties of iron-graphite materials as a function of the graphite content of their charges is described by equations of the third degree.