Keiichiro Shoji

On the Sintering of Fe-Ni and Fe-Ni-P Compacts

Iron-nickel and iron-nickel-phosphorus powder mixtures were pressed and sintered. The diffusion of nickel in the sintered specimens and the sintering process of the pressed compacts were studied. The results obtained are as follows:(1) The temperature of α→γ transformation for sintered iron-3% nickel specimen decreases with decreasing sintering time owing to the nickel rich areas in the specimen.(2) It was found that the diffusion of nickel is accelerated in the sintered iron-3% nickel-0.5% phosphorus specimen. This may be attributed to the faster diffusion of nickel into the b.c.c. iron formed by preferential diffusion of phosphorus.(3) In the sintered iron-3% nickel-0.5% phosphorus specimen prepared by the addition of nickel-phosphorus mother alloy powder, the diffusion of nickel is retarded by the interaction of nickel and phosphorus.(4) When nickel and phosphorus increase in the compact, nickel phosphide is formed during sintering. Thus the sintering process is similar to that of iron plus nickel-phosphorus mother alloy powder compact.