NICKEL-RICH PORTION OF NICKEL-CADMIUM SYSTEM

Constitution of the Ni-Cd phase- diagram has been explored by x- ray diffraction and microscopy, principally at its high-nickel end, but also with reference to the overall system. No primary solid solubility of Cd in Ni exists. The NICd beta compound equilibrates directly with nickel, with no further compound intervening. The unknown crystal structure of NiCd has been determined as being of the eta-carbide (E9//3) type, with aO (typically) equals 11. 387 A and x-ray density 9. 18. g/cc. NiCd has a small homogeneity range and decomposes peritectically at about 680 C.