Iron-Phosphorus based soft magnetic materials are known for their hot and cold shortness. The present investigation deals with the development of high-density Fe-P based alloys in the form of very thin sheets (0.1mm) by proper soaking of them at a high temperature so as to eliminate Iron-Phosphide eutectic and bring the phosphorus entirely into solution in the iron. It has also been possible to eliminate the use of a hydrogen atmosphere during sintering by using carbon to form CO gas within the compact by reaction with the oxygen of the iron powder particles. A glassy ceramic coating applied over the compact serves as a protective coating in order to avoid atmospheric oxygen attack over the compact held at high temperature. The Fe-0.3wt% P- 0.4wt% Si alloy so formed yielded coercivities as low as 0.42 Oe, resistivities as high as 28.4 µΩcm and total losses as low as 0.132 W/Kg. Such a combination of properties may make the alloy suitable for application in magnetic relays and transformer cores.