The influence of phosphorus (0.15 wt.%) on iron oxide scale adhesion is studied for short time oxidation of carbon steel in air at 800 and 1000 degrees C. Adhesion is measured after cooling to room temperature by Vickers indentation. It is shown to increase with increasing oxidation time as the result of the formation of a phosphorus-containing phase at the steel-scale interface. It also exhibits much higher values after oxidation at 1000 degrees C than after oxidation at 800 degrees C. This is suggested to be due to molten oxide infiltrating the metal grain boundaries during oxidation at the highest temperature. The FeO-Fe-3(PO4)(2) eutectic temperature of 940 degrees C appears therefore as a critical parameter in the steel descaling process on the production line. (C) 2014 Elsevier B.V. All rights reserved.