This Small Business Innovation Research Phase I project should improve the magnetic and tensile properties of phosphorus iron parts fabricated using the P/M process. The phosphorus irons fabricated using P/M technology are being widely used in industry today. They are formulated by admixing iron powder with Fe2P or Fe3P powder. During sintering, a liquid phase occurs at 1056oC (1950oF) which diffuses the phosphorus into solid solution in the iron. Problems exist in that only two powder producers sell the product, and large pores can remain in the sintered part, owing to the melting of the ferrophosphorus particles. Several attempts have been made to coat the phosphorus on the iron prior to sintering.(l) The first attempt was to add P205 to methanol and spray it on the iron powder. The trial resulted in failure because the phosphorus did not reduce the oxide or the water atomized powder, and perhaps provided additional oxide which acted as a barrier. A second series of tests were made by introducing phosphine to the heated bed of iron powder. Although magnetic and tensile properties were significantly improved, phosphine is expensive, and safety precautions preclude its use. Red phosphorus is not a safety problem. If hydrogen is introduced to the heated iron powder, it will reduce the surface oxide. A clean surface would then be available to accept the phosphorus coating, and the particles could be coated inexpensively and with no safety concerns. It is believed that the same improvement in properties would result from this process. If the process is successful, the proposer would consider construction of a plant to furnish coated phosphorus iron powder for commercial usage. Licensing of the process would also be considered. A market for the powder is already established. P/M phosphorus iron parts are currently widely used in fuel injectors and sensors in present day automobiles. They are also widely used for relays, solenoids and other magnetic devices. The introduction of a coated phosphorus iron powder to the marketplace would result in more efficient, reliable magnetic devices that would be lighter or more power efficient.
