Each material surface is exposed to various environmental influences. The surface of a solid body is subjected to corrosion and wear and interacts with light and electromagnetc fields. From the technological point of view the miniaturization of mechanic, electronic, optical and optoelectronic components permanently increases the surface to volume ratio of the involved materials. In modern material science specific surface properties therefore gain increasing importance.Nonetheless, the desired mechanical, optical chemical or electronic properties are often opposed to the bulk properties which may be high mechanical stability, easy manufacturing or low material cost. Because of this fact a multitude if High Tech components are composite materials which means that the surface properties significantly differ from the bulk properties. An example may be a mechanical part which has to exhibit high hardness (i. e. low wear under tribological load) as well as high fracture toughness (i. e. high resiestance against crack propagation). One material alone may not fulfill these demands. The solution of the problem can be a composite material consisting of a surface zone (coating) with high surface hardness and a tough bulk core.
đang được dịch, vui lòng đợi..
