Structure and morphology of electroless Ni–P deposits

The high-voltage electron microscope has been used to study the structure and morphology of electroless Ni–P deposits of varying phosphorus contents. Except for low (<3 wt-%) phosphorus contents the deposits are amorphous. The crystallization processes depend on a number of variables, including thickness and phosphorus content of the deposit and presence or otherwise of an iron substrate. These processes include epitaxial crystallization of Ni2.55P, spherulitic (or dendritic) crystallization of Ni2.55P and Ni3P, precipitation of nickel particles, and structures arising from interdiffusion between nickel, phosphorus, and the substrate.MST/660