Wear is discussed in terms of its damaging affect on changes of topography of the surface. volume of material removed, transitions in behaviour, and the effect of wear debris on performance of engineering systems. Friction and wear are characteristics of the engineering system and improvements may be obtained by changing operating parameters and condition of the wear surface, or by. optimizing the wear counterface combinations. Wear mechanisms are described, largely from the observations obtained from the use of scanning electron microscopy and, of these, wear under abrasive and metal-to-metal sliding conditions is most often encountered in industrial machinery. The study of wear is now becoming both more widespread and more fundamental and considerable efforts are being made to develop improved surfaces. Surface coatings, surface treatments, and the use of powder metallurgy are becoming more widespread to combat the extremely difficult conditions encountered at tribological surfaces. PM/O177exploration, production, and process plants than any other components. TE 99 通用摩擦磨損試驗機(jī)