An analysis was made of the structure of the Ni deposit produced by the catalytic Ni reduction process. X‐ray and electron diffraction revealed that the Ni deposit was an amorphous solid. The structure appeared to be unrelated to and independent of the nature of the substrate and thickness of the deposit.Metallographic examination revealed a dense material, free of voids, and perfect conformity to the substrate surface profile. Etching produced a lamellar structure, the variation in etching intensity being interpreted as variations in dissolved P. In platings, the lamellae lay parallel to the plane of the substrate. Growth faults were observed traversing the thickness dimension from substrate surface irregularities. The amorphous structure reverted to a crystalline phase mixture of Ni and at low temperatures with a large heat evolution.