THE SCANNING MICRO-SCLEROMETER - A NEW METHOD FOR SCRATCH HARDNESS MAPPING

A new surface engineering research tool, called a scanning micro-scler ometer (SMS), has been developed. It uses nano-indentation technology and a piezoelectric transducer positioning system to generate high-pre cision scratch patterns on the surfaces of metals and, by monitoring t he instantaneous displacement of the stylus tip, can generate scratch hardness and scratching force maps of the surface. A dual-stroke proce ss is used, The first stroke at low load profiles the surface to estab lish a reference datum and the second pass, in the opposite direction and at higher load, produces the indentation scratch, Examples of micr o-scratch hardness mapping experiments, using scratch spacings of 1.0 mu m, on a silicon carbide-based ceramic composite are used to illustr ate the capabilities of the SMS. Using end-on fibers in the rectangula r stylus scanning area, the difference in scratch hardnesses of the fi bers, the matrix, and even the thin carbon coatings in the fiber-matri x interface could be detected. The SMS was originally developed to pro duce scratch hardness maps, but it is also useful for conducting accur ately controlled, single-point micro-machining patterns and in studies of differential material abrasion. (C) 1997 Elsevier Science Ltd.