Dissolution kinetics of WO3 in acidic solutions
Potentiostatic polarization and rotating disk electrode techniques were used to obtain the rate constant for the dissolution of electrochemically-formed (at 1 V) WO3 on tungsten (W) in acidic solutions. The corresponding rate constant for the chemical dissolution of WO3(s) powder was found by measuring the dissolved tungsten concentration as a function of time and pH. The chemical dissolution experiments supported the view that the rate-determining step in the anodic reaction of W in acidic solution is the chemical dissolution of WO3(s) formed on the metal surface. Zeta potential measurements gave the isoelectric point (iep) of the WO3(s) powder as pH 1.5, a value that was somewhat smaller than the point of zero charge (pzc) of WO3(s) formed on W metal (pH 2.5). This difference was attributed to the highly hydrated nature of the oxide film formed on W metal in aqueous systems.
KeywordsCMP dissolution kinetics rate constant tungsten tungsten oxide
Unable to display preview. Download preview PDF.
- 4.S. Basak, K. Mishra, B. Withers and K. Rajeshwar, in S. Raghavan and I. Ali (Eds), First Int. Symp. Chemical Mechanical Planarization, Vol. 96-22 (Electrochem. Soc. Proc., Pennington, NJ, 1997) p. 137Google Scholar
- 5.C. Raghunath, K.T. Lee, E.A. Kneer, V. Mathew and S. Raghavan, in S. Raghavan and I. Ali (Eds), First Int. Symp. Chemical Mechanical Planarization, Vol. 96-22 (Electrochem. Soc. Proc., Pennington, NJ, 1997) p. 1Google Scholar
- 9.Tamboli D., Seal S., Desai V. (1999). J. Vac. Sci. Technol. A 17:1168Google Scholar
- 21.Anik M., Cansızoglu T., Cevik S. (2004). Turk. J. Chem. 28:425Google Scholar
- 22.Pleskov Yu.V., Filinovskii V.Yu. (1976). The Rotating Disc Electrode. Plenum, New York, p. 1Google Scholar
- 23.Bard A.J., Faulkner L.R. (2001). Electrochemical Methods Fundamentals and Applications. John Wiley, New York 2nd Ed. p. 331Google Scholar
- 26.S.M. Ahmed, in J.W. Diggle (Ed), ‘Oxides and Oxide Films’, Vol. 1, (Marcel Dekker, New York, 1972) p. 319Google Scholar
- 27.Stumm W. (1992). Chemistry of the Solid – Water Interface. John Wiley, New York p. 157Google Scholar