Nanometer Resolution of Reactive Sites on Heterogeneous Metal Surfaces

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

This grant explores high-resolution topographic imaging with concurrent optical, electrochemical, photoelectrochemical, and fluorescence mapping. These techniques are based on novel modifications of a commercial Near Field Optical Scanning Microscopic (NSOM Topometrix) to obtain shear force feedback control with a piezoelectric tuning fork. Optical resolutions of 60 nm and electrochemical resolutions of 50 nm have been achieved for these functional microscopies. This research is aimed at extending these resolutions to 10 nm or below. In addition a study of pitting precursor sites will be made for high purity titanium, titanium alloys, and aluminum alloys. This should facilitate in-situ and ex-situ evaluation of surface treatments used to mitigate pitting corrosion. A primary goal of this work is to develop these high-resolution capabilities to identify precursor sites for corrosion of microelectronic and magnetic storage assemblies. As the dimensions of these and similar devices decrease, corrosion becomes increasingly important and techniques to explore heterogeneous surfaces are needed. Magnetic storage surfaces can be covered with diamond-like carbon coatings to provide tribological protection, and it is important to determine how well these surfaces protect against corrosion as well. Scanning electrochemical microscopy with concurrent topographic mapping is the primary technique used for the studies. A secondary goal is to employ these successful characterization techniques for fabrication of novel surface structures.