ENERGY-DISPERSIVE X-RAY-ANALYSIS OF ELECTROLESS NICKEL COATINGS

In order to produce implants useful for hyperthermic treatment of cancerous tumors, the ferromagnetic materials used for eddy-current heating must be homogeneous. For this application, the magnetic permeability must change as sharply as possible at the Curie temperature and the sharpness of the transition is directly related to the homogeneity of the material. Ni-P alloys plated from solution (electroless nickel) are being considered for ferromagnetic implants. In order to determine the composition and the degree of homogeneity of Ni-P alloys, four foils previously analyzed by wet methods were examined using energy-dispersive x-ray spectroscopy (EDS). Cobalt was detected at a concentration of about 1 weight percent (w/o) in one sample. All samples contained trace amounts of silicon and iron. With the exception of one foil, the average phosphorus content across the foils using EDS were within 0.5 w/o of those determined by the wet method. Only one foil which was deposited electrolytically was found to be homogeneous. Suggested improvements in microanalysis techniques for further investigations include more precise placement of the end points in line profiles. The degree of homogeneity which can be achieved in Ni-P plating will also be investigated. © 1990, The Electrochemical Society, Inc. All rights reserved.