Passivation of Laser-Treated Nickel Aluminum Bronze as Measured by Electrochemical Impedance Spectroscopy


  1. Klassen, R.D.
  2. Hyatt, C.
  3. Roberge, P.R.
Corporate Authors
Royal Military Coll of Canada, Kingston ONT (CAN) Dept of Chemistry and Chemical Engineering;Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Although laser welding and cladding of nickel aluminum bronze (NAB) surfaces involves a fraction of the energy input of conventional welding, a heat affected zone (HAZ) is still formed as well as an as-deposited zone. The main objective of this work was to determine whether the corrosion resistance of the HAZ due to laser treatment was different from the as-deposited zone or a surface without laser treatment. Electrochemical impedance spectroscopy (EIS) was employed to measure the corrosion rates of samples immersed in 3.5% neutral saline. The following specimens of a nickel aluminum bronze (Alloy D) were tested over an immersion time of 50 hours: (i) polished (not laser treated), (ii) laser-treated and polished, (iii) the as-deposited region of laser-treated and polished specimen, (iv) the HAZ region of a laser-treated and polished specimen and (v) laser-treated and unpolished. A pseudo steady-state level of passivation was reached in all the samples within 40 hours. As expected, laser treatment increased the short-term rate of passivation and therefore improves the long-term resistance to corrosion. The HAZ region clearly passivated more slowly than the as-deposited region. The long-term susceptibility of part of the HAZ to corrosion was confirmed with SEM micrographs. TRUNCATED
Nickel aluminum bronzes;Laser cladding;Electrochemical impedance spectroscopy
Report Number
DREA-SR-1999-162-PAP-21 — CONTAINED IN CA000150
Date of publication
01 Oct 1999
Number of Pages
Hardcopy;Document Image stored on Optical Disk

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