A Study of Manganese Phosphating Reactions
ARMY WEAPONS COMMAND ROCK ISLAND IL RESEARCH DEVELOPMENT AND ENGINEERING DIRECTORATE
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Work was conducted to determine the composition of and the reactions associated with the formation of manganese-phosphate coatings. An improved phosphate coating was studied as produced from a stock manganese phosphating bath to which an addition of manganese citrate, tartrate, or gluconate was made. Processing was accomplished in an autoclave at temperatures above 212F with steam pressure. The coatings produced by conventional and pressure methods were examined by differential thermal analysis, X-ray diffraction, and atomic absorption analysis. The chemical structure of the conventional coating was Fe3PO42.2MnHPO4.4H2O, a form of hureaulite, and that of the pressure phosphate coating was mainly manganese phosphate heptahydrate, Mn3PO42.7H2O.
- Coatings, Colorants and Finishes