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The first major scientific study of diamond polishing was by Tolkowsky. His model dominated until recent years, when high-resolution microscopes allowed detailed studies of polished diamond surfaces. In this paper, new research shows that diamond polishing involves two-and three-body wear processes. The third body consists of the sp 2 detritus formed while wearing diamond, and also minute diamond particles following comminution in the scaife preparation process. Microscopy also shows that diamond particles embedded in the scaife orient themselves to positions favourable for polishing. These particles are responsible for the formation of nano-grooves observed on diamond surfaces. In addition, measurements are presented that show that the wear mechanism for diamond is velocity dependent, and related to changes in material properties caused indirectly by the heat induced through frictional sliding.

A source of x-rays capable of exciting the characteristic emission lines of Mo and Ag is demonstrated. The device, which requires no external high voltage supply, uses the triboelectric effect to produce a charge imbalance when silicone and a metal-loaded epoxy are made to repeatedly contact each other in vacuum. This provides a source of 40 keV electrons which generate bremsstrahlung and characteristic x-rays at a rate of >105 per contact cycle. By increasing the repetition rate of the contact cycle the viability of a device that emits 108 x-ray photons per second is suggested, making triboelectricity an inexpensive source of x-rays. The form factors and simplicity of such devices open up interesting possibilities for x-ray imaging.

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