National University of Science and Technology “MISIS”, Moscow, Russia

A. A. Ermolaev, Assistant Professor

M. N. Sorokin, Senior Researcher
A. I. Laptev, Leading Researcher, e-mail: laptev@misis.ru

“Scientific and Research Institute of Natural and Synthetic Diamonds and Instrument” (VNIIALMAZ), Moscow, Russia

A. V. Nozhkina, Head of Laboratory
L. M. Kryukova, Senior Researcher

Nowadays, one of the widely used types of equipment for the processing of tempered steel and iron is the cutting instrument, made from the Superhard Composite Materials (SCM), on the basis of the Dense Forms of Boron Nitride (DFBN). The boron nitride has several crystallographic forms. The mechanical properties of various forms of boron nitride are essentially different. If the hexagonal form is applied as a lubricant, the sphalerite form possesses the high hardness conceding only to the diamond properties. The basic method of the production of SCM DFBN is their synthesis at high pressures and temperatures. The Elbor-R and Hexanite-R are the basic types of SCM DFBN, widely applied in industry. Elbor-R is synthesized with catalyst, from hexagonal boron nitride at the temperature above 2000 K and the pressure above 8,0 GPa. Hexanite-R is synthesized from the wurtzite boron nitride at the temperatures and pressures with the essentially lower values than for the Elbor-R synthesis. This research paper is devoted to the development of nondestructing method of the quality monitoring of the given types of composites. The developed method allows to classify the SCM DFBN materials into groups, which are suitable for manufacturing of various kinds of the tools. According to the results of the current research, it is possible to draw the following conclusion: monitoring of density in combination with the visual control is sufficient for the Elbor-R samples classification on their working capacity. It is not enough for the nondestructing control of Hexanite-R composites to carry out only their visual classification, but it is necessary to define their phase structure. It is enough for the proper phase control of the Hexanite-R samples to define the content of boron nitride hexagonal, which completely characterizes their working capacity. The content of boron nitride hexagonal in Hexanite-R must be considered according to the comparative intensity of 002 boron nitride hexagonal and 111 boron nitride sphalerite lines, which are easily identified.

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