Localization and chemical state of the third element (Zn, W) in electrolessly deposited nanocrystalline Ni-Zn-P, Ni-W-P and Co-W-P coatings

摘要

Electroless deposited Ni-P and Co-P coatings, modified by introducing additional elements such as Zn and W are presented. The characteristics alterations of the multicomponent films are reviewed in connection with the particularities of co-deposition of the third metal. Based on the fair correspondence between TEM, microdiffraction and precise XRD analysis it is shown that the structure type and lattice parameters of polycrystalline Ni-Me-P and Co-Me-P films are practically identical to pure Ni and Co metals. No impurity phase is detected by XRD. The location of the third element is determined using TEM with EDS. The conclusion is drawn about the grain boundary segregation of Zn and W along with P. Earlier studies by XPS and AES showed that Zn is partially oxidized, whereas W is in elemental form inside the coatings. Crystallites built of lamellas with thickness within the nanometer scale are observed in Ni-W-P and Co-W-P by TEM.