Comparison of Different Metal Matrix Systems for Diamond Tools Fabricated by New Current Induced Short-Time Sintering Processes

摘要

Diamond tools are mainly used for the cutting and grinding of stone and concrete. The circular saws, frame saws and drill bits consist of small diamond impregnated metal matrix segments, whose embedded diamonds are responsible for the cutting process. A well adjusted hardness of the metal matrix compared to the machined mineral material leads to aself sharpening process of the diamonds which guarantees good wear behavior [1]. Another important aspect regarding the wear resistance of these tools is the interface area between diamonds and metal matrix. The existence of a chemical reaction zone consisting of carbides or solid solutions has an advantageous influence at the diamond bonding. In this case Sung and Tai describe the reaction behavior of carbon with important transition metals. Generally the reactivity of metals against carbon depends on the number of electron vacancies in d-orbitals. Metals with a low number of vacancies (copper, zinc) are almost inert against carbon. In contrastmetals with many free d-orbitals (titanium, chromium) show a tendency to form carbides or are carbon solvents [2].Diamond grinding segments are generally fabricated powder metallurgically. The conventional production cycle consists of a preforming step at high pressure with a adjacent freestanding sintering under vacuum or the hot pressing where compaction and sintering is