AVS 49th International Symposium
    Surface Science Thursday Sessions
       Session SS-ThA

Paper SS-ThA7
Tribochemical Wear of Silicon Nitride on Oxide Surfaces Studied by Atomic Force Microscopy

Thursday, November 7, 2002, 4:00 pm, Room C-110

Session: Tribology at Surfaces
Presenter: J.T. Dickinson, Washington State University
Authors: J.T. Dickinson, Washington State University
W. Maw, Washington State University
F. Stevens, Washington State University
S.C. Langford, Washington State University
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Nanometer scale tribochemical wear of silicon nitride AFM tips was characterized on a variety of substrates in aquous solutions using atomic force microscopy. Wear at this small scale contrasts markedly with the macroscopic wear of silicon nitride. For aquous mediated wear, a chemically active substrate (one with the appropriate surface metal-hydroxide bonds) is required. These results are generally consistent with wear due to the formation and breaking of chemical bonds between the tip and the substrate. The wear rates are shown to be nonlinear in the applied normal force. We propose that stress-induced intermediate states involving hydroxyl groups form on both the AFM tip and the substrate. Chemical reactions subsequently form transient bridging chemical bonds that are responsible for tip wear.