Volkohon V. Physical and Technical Bases for Obtaining and Control of Forming Characteristics of Tool Polycrystal Superhard Materials Based on Wurtzite-like Boron Nitride.

This work is devoted to development of new types of polycrystal superhard materials with heightened physical and mechanical as well as work characteristics based on wurtzite-like boron nitride, and to control of principles for their properties forming. The solution of scientifical and practical problem under lies in study of appropriateness of phase and structure transformation in wurtzite-like boron nitride under effect of preliminary cold deformation by rolling with presence of shearing stress or at loading under conditions changing stress-strain state of powders and also at hot pressing under conditions of high pressure with presence or absence of additives. The technology of preliminary processing of wBN powders by rolling when preparing of super-hard powder materials as resulted from the researches conducted, has been implemented at the company "Poltava Diamond Plant", and cutting plates made of polycrystals of diameter up to 14 mm have been industrially tested while machining of components of mining equipment produced of steel 110G13 L, thus showing a durability 2 to 3 times higher compared to its analog.