Peak-profile analysis of electroless nickel coatings

Peak-profile analysis (PPA) of X-ray diffraction patterns and differential scanning calorimetry of electroless nickel (EN) coatings were done to determine the changes in the structure with annealing. As-deposited medium phosphorus EN coating exhibit broadened X-ray reflections indicative of a semi-amorphous structure. Heat-treatment decreased the amorphous phase which contributed to broadening of the reflections. A small exotherm was seen in the temperature range where the amorphous phase decreased and the crystalline component increased. No amorphous component was detected above 300°C. Changes in particle size did not occur until the annealing temperature exceeded 300°C. The strain in the EN coatings decreased sharply after 200°C and was negligible after 400°C heat-treatment.