ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Raman spectroscopy and atomic force microscopy have been used to investigate the composition and surface structure of polyacrylic acid modified zinc phosphate crystal conversion coatings on steel. Zinc phosphate coatings are used extensively to provide corrosion protection and to improve adherence of topcoatings to steel. Within the last few years it has been demonstrated that addition of high molecular weight polyacrylic acid (PAA) to the phosphating bath can significantly improve both resistance to corrosion and topcoat adherence. It has been reported that the addition of PAA reduces the size of crystallites, which leads to greater film ductility, and therefore to fewer sites for corrosive attack, and that organic molecular segments from the PAA are incorporated into the surface structure and provide additional adhesive bonding with polymeric topcoats. In this work Raman spectra show the compositions of both unmodified and PAA modified films to be zinc phosphate dihydrate, Zn3(PO4)2·2H2O. Atomic force microscopy (AFM) was used to measure the morphologies of single crystallite surfaces. Morphologies of the unmodified and modified films obtained by AFM are in general quite similar, but subtle differences are apparent. © 1993 John Wiley & Sons, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1993.070500520
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