The scanning tunneling microscope is proposed as a method to measure forces as small as 10-18 N. As one application for this concept, we introduce a new type of microscope capable of investigating surfaces of insulators on an atomic scale. The atomic force microscope is a combination of the principles of the scanning tunneling microscope and the stylus profilometer. It incorporates a probe that does not damage the surface. Our preliminary results in air demonstrate a lateral resolution of 30 A and a vertical resolution less than 1 A.

https://link.aps.org/pdf/10.1103/PhysRevLett.56.930

Atomic force microscope

The atomic force microscope (AFM) is a promising new method for studying the surface structure of both conductors and insulators. In mapping a graphite surface with an insulating stylus, we have achieved a resolution better than 2.5 A.

https://iopscience.iop.org/article/10.1209/0295-5075/3/12/006/pdf

Atomic Resolution with Atomic Force Microscope

I was introduced to vacuum tunneling high over the Atlantic while flying to London in April 1982. For months prior to that flight I had been fretting about the future work of our microscopy research group at Stanford. We had just completed our work in acoustic microscopy and were looking for new directions. I was considering a variety of problems, such as the building of an x‐ray microscope, but nothing would fall into place. I thought that a trip to a conference in London might provide some time to get away and think. On the way to the airport I stopped by my office and picked up the latest issue of this magazine. I think we were over Iceland when I opened it and found a report (PHYSICS TODAY, April 1982, page 21) on a new form of scanning microscopy being developed in Zurich. In London, I changed my travel plans and went to Zurich. It proved to be the start of an adventure for our group, an adventure that still continues, undiminished in excitement.

Vacuum Tunneling: A New Technique for Microscopy

Prediction of abrasion wear for slurry pump materials

A singular class of polymer reactions can be caused by mechanical stress. Sufficient storage of mechanical energy to break chemical bonds in the main chain is generally possible only on deformation of polymers of high molecular weight. The corresponding appropriate conditions of high stress may occur in both polymer processing and use. This review summarizes reports of such polymer stress reactions published principally after 1980. The survey is organized by polymer type and by analysis technique.

Recent studies of polymer reactions caused by stress

Impact wear testing machine

Impact wear model for steel specimens

Impact wear phenomena in thin polymer films

Study of surface topography in impact wear

Scattered data exist in the literature on the chemical reactions which occur during mechanical contact. It is our contention that these reactions occur as a direct result of the high temperatures generated at the contact interface, due to the dissipation of mechanical energy. A theoretical analysis is used to identify and rank the various sources of heat generation during repetitive impact or sliding. New data, on both filled and unfilled polymers and elastomers, supported by data from the literature, are used to show that the resultant temperature rise causes reactions at the interface; the extents of these reactions depend on the polymer structure and the magnitude of the temperature rise. Several ways of reducing the magnitude of this temperature rise are discussed.

P.A. Engel

Papers

Impact wear testing machine

Impact wear model for steel specimens

Impact wear phenomena in thin polymer films

Study of surface topography in impact wear

Mechanochemical aspects of repetitive impacts and sliding on polymers