THE METAL-RICH PART OF THE CO-NI-P SYSTEM AT 800 °C

Abstract

The metal-rich portion of the Co-Ni-P system was studied experimentally at 800 °C by means of evacuated silica glass tube technique. Five binary phases: Co2P, Ni2P, Ni12P2 Ni 5 Ni3P and ive ternary phosphides solid solutions: (Co1-x,NixP,λ (Ni1-xCox) 2P (hexagonal), λ-(Co1-xNix) 2P (orthorhombic), (Co1-xNix)12 P5and (Co1-xNix)5P2 were found to be stable in the system. Cobalt has a significant influence on the structure of (Ni,Co)2P solid solutions and, therefore, cobalt contents might change the crystal structure of naturally occurring phosphides with the Ni/P = 2:1 ratio. Ni-rich, cobalt-containing phosphides with the Ni/P ratio = 3:1 and 2:1, isotypic with minerals schreibersite and barringerite, could possibly be found in meteorites. Likewise, phosphides with Ni/P ratio = 12:5 and 5:2 may possibly be found, but in close association with natural Ni-rich phosphides. © 2006 E. Schweizcrbart'schc Verlagsbuchhandlung.