@article {2007,
	title = {Microstructural effects on the formation and degradation of zinc phosphate coatings on 2024-Al alloy},
	journal = {Applied Surface Science},
	volume = {254},
	number = {15},
	year = {2008},
	note = {ISI Document Delivery No.: 295YWTimes Cited: 2Cited Reference Count: 26Akhtar, A. S. Wong, P. C. Wong, K. C. Mitchell, K. A. R.},
	month = {May},
	pages = {4813-4819},
	type = {Article},
	abstract = {The formation of zinc phosphate (ZPO) coatings on 2024-T3 aluminum alloy was studied using scanning electron microscopy (SEM), scanning Auger microscopy (SAM) and X-ray photoelectron spectroscopy (XPS), with an emphasis on microstructural effects involving second-phase particles and the alloy matrix. Surface polishing results in an Al-Cu-Mg particle surface that contains metallic Cu as well as an overlayer of aluminum and magnesium oxide, while larger amounts of aluminum oxide are present on the Al-Cu-Fe-Mn particle and matrix. When dipped in an acidic ZPO coating solution, the oxide covering the Al-Cu-Mg particle is etched most easily, and metallic Cu near the surface makes that region most cathodic, allowing more coating deposition compared with the other regions. The oxides on the Al-Cu-Fe-Mn and matrix regions are similar, thereby confirming that the observed differences in ZPO coating characteristics at these two regions arise from their underlying electrochemical characteristics. Immersion of a coated 2024-Al sample in corrosive NaCl solution for extended periods indicates that the ZPO provides better protection to the second-phase particles than to the matrix. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {7075-T6, ALKALINE STABILITY, aluminum alloy, ALUMINUM-ALLOY, Auger electron spectroscopy, BEHAVIOR, corrosion, CORROSION PROTECTION, INITIATION, MICROSTRUCTURE, NI2+, PARTICLES, PHASE, surface oxide, zinc phosphating},
	isbn = {0169-4332},
	url = {<Go to ISI>://000255511700063},
	author = {Akhtar, A. S. and Wong, P. C. and Wong, K. C. and Mitchell, K. A. R.}
}
@article {1326,
	title = {The effect of pH and role of Ni2+ in zinc phosphating of 2024-Al alloy. Part I: Macroscopic studies with XPS and SEM},
	journal = {Applied Surface Science},
	volume = {253},
	number = {2},
	year = {2006},
	note = {ISI Document Delivery No.: 114DVTimes Cited: 10Cited Reference Count: 30Akhtar, A. S. Wong, K. C. Mitchell, K. A. R.},
	month = {Nov},
	pages = {493-501},
	type = {Article},
	abstract = {Coatings formed on 2024-T3 aluminum alloy were studied by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) after dipping in zinc phosphating (ZPO) baths at different acidities, for different lengths of time, and with or without Ni2+ additive. The overall objective was to learn more about the role of Ni2+ on the ZPO coating mechanism, particularly since this additive is believed to improve corrosion protection for the Al alloy. Secondary phosphates dominate the coatings when the Ni-containing solution is adjusted to starting pH values of either 3 or 5, while tertiary phosphate is predominant at pH 4. AlF3 precipitates during the early stages of the coating process. Ni2+ has two main roles in the mechanism. First, the rate of increase in local solution pH is retarded by the slower kinetics of reactions involving Ni2+ compared to Zn2+,leading to thinner ZPO coatings when Ni2+ is present in the coating solution. Second, most Ni2+ deposition occurs during the later stages of the coating process, by nickel phosphate deposition and/or by formation of a Ni-rich oxide. (c) 2006 Elsevier B.V. All rights reserved.},
	keywords = {ALKALINE STABILITY, aluminum alloy, ALUMINUM-ALLOY, CATALYSTS, COATINGS, CONVERSION COATINGS, FILMS, Ni2+ additive, NICKEL, OXIDATION, photoelectron spectroscopy, scanning electron microscopy, SPECTROSCOPY, STEEL, zinc phosphate},
	isbn = {0169-4332},
	url = {<Go to ISI>://000242647800017},
	author = {Akhtar, A. S. and Wong, K. C. and Mitchell, K. A. R.}
}
@article {1325,
	title = {The effect of pH and role of Ni2+ in zinc phosphating of 2024-Al alloy. Part II: Microscopic studies with SEM and SAM},
	journal = {Applied Surface Science},
	volume = {253},
	number = {2},
	year = {2006},
	note = {ISI Document Delivery No.: 114DVTimes Cited: 13Cited Reference Count: 11Akhtar, A. S. Susac, D. Wong, P. C. Mitchell, K. A. R.},
	month = {Nov},
	pages = {502-509},
	type = {Article},
	abstract = {Coatings formed on 2024-T3 aluminum alloy were studied by scanning electron microscopy (SEM) and scanning Auger microscopy (SAM) after dipping in zinc phosphating (ZPO) baths at different acidities, with or without the Ni2+ additive. The objective was to learn more about the ZPO coating mechanism on the different microstructural regions of 2024-T3. When the initial coating solution pH is 4 (optimal acidity), a slower etching rate at the Al-Cu-Fe-Mn intermetallic particle{\textquoteright}causes significant precipitation of ZnO, which differs from the coating on other regions of the surface where phosphate predominates. The larger crystals (similar to mu m dimension) on the matrix and the Al-Cu-Mg particle contain more phosphate compared to other areas on the surface. When Ni2+ is added to the coating solution, the Al-Cu-Mg particle is more thickly coated compared to when the Ni2+ is not present. The slower rate of precipitation when Ni2+ is present in the coating solution increases the exposure of the alloy substrate to the acidic environment, so allowing more dissolution of Mg and Al from the Al-Cu-Mg particle. This results in the particle becoming more cathodic in nature, and therefore more coating deposits at this location. Evidence from SAM supports the presence of NiAl2O4, hypothesized in Part I, forming at coating pores later in the process. (c) 2006 Elsevier B.V. All rights reserved.},
	keywords = {aluminum alloy, ALUMINUM-ALLOY, Auger electron spectroscopy, COATINGS, CONVERSION COATINGS, Ni2+ additive, scanning electron microscopy, zinc phosphate},
	isbn = {0169-4332},
	url = {<Go to ISI>://000242647800018},
	author = {Akhtar, A. S. and Susac, D. and Wong, P. C. and Mitchell, K. A. R.}
}
@inbook {1324,
	title = {Surface science studies of the effect of Mn2+ on zinc phosphating of 2024-T3 Al alloy},
	booktitle = {Aluminium Alloys 2006, Pts 1 and 2 - Research through Innovation and Technology},
	series = {Materials Science Forum},
	volume = {519-521},
	year = {2006},
	note = {ISI Document Delivery No.: BEZ41Times Cited: 1Cited Reference Count: 10Akhtar, A. S. Susac, D. Wong, K. C. Wong, P. C. Mitchell, K. A. R.Proceedings Paper10th International Conference on Aliminium Alloys (ICAA-10)JUL 09-13, 2006Vancouver, CANADABRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND},
	pages = {753-758},
	publisher = {Trans Tech Publications Ltd},
	organization = {Trans Tech Publications Ltd},
	address = {Zurich-Uetikon},
	abstract = {The present work is part of a broader investigation of the effects of additives in zinc phosphate (ZPO) coating solutions that are designed for specific applications to Al and its alloys. ZPO conversion coatings improve the corrosion resistance of the Al substrate and increase the adhesion of paint. Coatings formed on 2024-T3 aluminum alloy, after dipping in ZPO coating baths containing Mn2+, have been studied by X-ray photoelectron spectroscopy (XPS), SEM, and scanning Auger microscopy (SAM). Variations are observed in coating morphology and composition as the amount of Mn2+ in the coating solution increases through the 0 to 2500 ppm range. Adhesion tests give information on the relative strength of the coating-substrate interaction at different microstructural areas.},
	keywords = {aluminum alloy, ALUMINUM-ALLOY, Auger, COATINGS, CONVERSION COATINGS, electron spectroscopy, Mn2+ additive, photoelectron spectroscopy, scanning electron microscopy, STEEL, zinc phosphate},
	isbn = {0255-54760-87849-408-1},
	url = {<Go to ISI>://000240309000118},
	author = {Akhtar, A. S. and Susac, D. and Wong, K. C. and Wong, P. C. and Mitchell, K. A. R.},
	editor = {Poole, W. J. and Wells, M. A. and Lloyd, D. J.}
}
@article {793,
	title = {The effect of Ni2+ on zinc phosphating of 2024-T3 Al alloy},
	journal = {Surface \& Coatings Technology},
	volume = {187},
	number = {2-3},
	year = {2004},
	note = {ISI Document Delivery No.: 860VHTimes Cited: 27Cited Reference Count: 32},
	month = {Oct},
	pages = {208-215},
	type = {Article},
	abstract = {Zinc phosphate (ZPO) conversion coatings formed on 2024-T3 aluminum alloy, and on high-purity aluminum, after dipping in coating baths containing different amounts of Ni2+, have been studied by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, scanning Auger microscopy (SAM) and electrochemical measurements. Significant variations are observed in coating morphology and in stability against corrosion for the 2024-Al alloy as the amount of Ni2+ in the coating solution increases through the 0-2000 ppm range. By contrast, for high-purity Al, the most marked changes in coating morphology occur only as the Ni2+ concentration reaches 2000 ppm. The presence of additional elements, and especially Cu, in the 2024-Al samples results in an increase in the number of cathodic sites and hence more coating is formed for corresponding conditions. Additionally, the existence of second-phase particles in the 2024-Al sample leads to variations in the coatings at the microstructural level across the surface. These differences include local variations in the amount of Ni2+ in the coatings, as well as the local coverage. (C) 2004 Elsevier B.V. All rights reserved.},
	keywords = {aluminum alloy, ALUMINUM-ALLOY, Auger electron spectroscopy, chemical conversion, CHROMATE CONVERSION COATINGS, CORROSION PROTECTION, FILMS, Ni2+ additive, NICKEL, phosphating, photoelectron spectroscopy, STEEL, SURFACE, XPS},
	isbn = {0257-8972},
	url = {<Go to ISI>://000224371300011},
	author = {Akhtar, A. S. and Susac, D. and Glaze, P. and Wong, K. C. and Wong, P. C. and Mitchell, K. A. R.}
}
