IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Thursday Sessions
       Session AS-ThA

Paper AS-ThA6
Correlation between Surface Topography and Corrosion Rate: An Investigation by Scanning Force Microscopy

Thursday, November 1, 2001, 3:40 pm, Room 134

Session: Adhesion and Corrosion
Presenter: J.E. Castle, University of Surrey, U.K.
Authors: J.E. Castle, University of Surrey, U.K.
P.A. Zhdan, University of Surrey, U.K.
P. Singjai, University of Surrey, U.K.
T. Simpson, University of Surrey, U.K.
Correspondent: Click to Email
In the course of our work with many metals, alloys and inorganic materials in media of differing levels of aggression we have found an interesting broad correlation between surface topography and the extent of aqueous corrosion. The correlation is particularly apparent when use is made of scanning force microscopy (SFM) to monitor surface roughness under conditions in which the extent of corrosion can be measured by an independent method - such as solution analysis. This enables corrosion rates to be inferred from in-situ or ex-situ measurements of surface topography, made by SFM, in media or with surfaces that are not amenable to normal means of corrosion rate measurement. We draw attention to this correlation using several examples, such as etching of copper, corrosion of duplex steel and ferritic steel in hydrochloric acid, or the corrosion of brass in aerated water, and corrosion of pottery glaze in alkaline wash, which have been chosen to illustrate the phenomenon in both etching and in oxidising conditions. Underlying reasons for the correlation are discussed and it is shown that a useful outcome of the work is that it permits measurements by in situ SFM to be used for interpolation or extrapolation of data obtained by electrochemical methods or by analysis of the corrodent solutions. The SFM as an instrument is becoming widely available and this method of measurement thus has a wide application. It is suggested that as more robust forms of the SFM instrument become available, there is the possibility of using this technique as a corrosion monitor under circumstances in which measurement of corrosion rate is difficult by more conventional methods.