Carbon reactivity of binder metals in diamond–metal composites – characterization by scanning electron microscopy and X-ray diffraction

• Published in: Diamond and related materials Vol. 38; pp. 118 - 123
• Main Authors: Tillmann, Wolfgang, Ferreira, Manuel, Steffen, Andre, Rüster, Karin, Möller, Johannes, Bieder, Steffen, Paulus, Michael, Tolan, Metin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2013; Elsevier
• Subjects: Binders; Bonding; Carbon; Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Cutting tool materials; Diamond machining; Diamond tools; Diamond-metal composites; Diamonds; Diffraction; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Interface reactions; Machining; Materials science; Phase analysis; Physics; Scanning electron microscopy; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Synchrotron; Thin film structure and morphology; X-rays; XRD; Diamond-metal composites; Diamond tools; XRD; Interface reactions; Synchrotron; Phase analysis; Diamonds; Machining; Iron; Minerals; Cobalt; Cutting; Interface reaction; Copper; Synchrotron radiation; Scanning electron microscopy; Diamond tool; Hard materials; Experimental study; Carbon; Composite materials; Sintering; Morphology; Transition elements; Chromium; Nickel
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2013.07.002

Diamond tooling is a successfully used technique in machining of very hard materials such as minerals and concrete. The type and strength of bonding between the diamond grains, that are mainly responsible for the machining process (e.g. cutting or grinding), and the metallic binder phase is directly linked to the tools quality. Therefore it is of interest to investigate the carbon reactivity of commonly used binder materials. This paper reports about the investigation of the interfacial area between diamonds and one-component metallic binder matrices. As matrix material pure chromium, cobalt, copper, iron, and nickel was used. After the sintering process the diamonds were extracted from the metallic matrix and analyzed by scanning electron microscopy and X-ray diffraction. The morphology of the diamond surface was investigated and a phase analysis was done. These experimental studies support the hypothesis that the carbon reactivity of transition metals is linked to their d-orbital electron configuration. •Chromium as a strong carbide former enforces a interfacial area which consists of a mixture of stable Cr3C2 and Cr7C3.•Contacting diamonds with iron, cobalt or nickel leads to an allotropic transformation to graphite at the surface.•Copper is carbon inert and no chemical reactions are visible.